Zinc in Leukemia
(c) by George Eby, Austin, Texas - December 1982.
Introduction. RATIONALE FOR STUDY AND SUMMARY OF FINDINGS
In a case of Acute Lymphocytic Leukemia (ALL)in a 3-year-old white female treated with CCG protocol 161, regimen 2 a bone marrow remission from 95+% blast cells to an observed zero blast cell count (not M-1 but M-0) occurred within 14 days of treatment.
During this same period adult therapeutic doses of all known vitamins (except folic acid) and all minerals and trace minerals were also given. In addition to the reduction of blast cells to an observed count of zero, red blood cell production and other hemopoietic functions returned to a modified normal condition at a clinically remarkable rate. No adverse effects of the chemotherapy were observed. Since most remissions after 30 days of treatment still show 3-5% blasts in the bone marrow, the question "Had there been an unknown but positive interaction between one or more of the supplemental nutrients and the chemotherapy?" was asked by the clinicians and parents. Research was initiated to ascertain if a nutrient deficiency could cause symptoms found in pre-leukemia and leukemia; and if such nutrient exists, would a positive interaction occur if it were administered as an adjunct to chemotherapy. If a nutrient could be shown to accelerate and strengthen the function of chemotherapy or the immune function, then it could be expected that the relapse rate could be lessened since the relapse rate to both the rate at which a remission is obtained and the thoroughness of the elimination of leukemic blasts.
Based upon a review of the available literature, only zinc deficiency or zinc metabolism errors could theoretically cause all of the pre-leukemic conditions of allergy, loss of viral and tumoral immunity, asparagine production, growth suppression and other commonly observed pre-leukemic conditions. It was noted that leukemic cells contain much less zinc than normal lymphocytes which may be very important since zinc is vital for proper genetic and cellular function. Zinc metabolism deviations have been recognized in leukemia since 1949, but not well understood, although zinc was used in the early 1950s as a therapeutic drug in the treatment of leukemia. Zinc may function therapeutically in leukemia by augmenting L-asparaginase in killing leukemic cells (since a zinc deficiency may induce free asparagine), and by stimulating cell mediated immunity. Zinc is believed to have been the only nutrient that could have had a positive interaction with any of the chemotherapeutic drugs in CCG protocol 161 regimen 2.
In the child's remission, zinc at 1-2 mg/pound of body weight was not observed to cause an increase in lymphocyte count, but may have improved T-cell immune function. Zinc may have aided in restoring normal growth while using corticosteroids in a monthly pulse protocol. Zinc is known to stimulate effector T-cell function and increase the number of effector T-cells, even in leukemia, which may have aided in the destruction of residual leukemic cells, through amplification of the plaque-forming cell function of T-cells. Zinc is the body's only T-cell lymphocyte activator.
In studies to ascertain the practical role of zinc in related hematological functions, zinc was found effective in increasing immunity to upper respiratory viruses and infections in general in normal people and leukemic children, management of Type I allergy and growth restoration in both normal and leukemic children. Therapy of the common cold with zinc yielded extremely rapid recoveries which strongly suggested that a zinc-viral antigen complex was highly stimulatory to interferon induction, and/or that the direct inhibition of rhinovirus by zinc may be highly practical and effective in vivo. Identical responses to zinc supplementation as an adjunct to standard treatment occurred in about one dozen children when zinc treatment was started with standard treatment between 1985 and 1997.
I. A SEARCH FOR THE ETIOLOGY OF LEUKEMIA
Pre-Acute Lymphocytic Leukemia in the child is often, but not always, marked by: (1) severe atopic-like allergic reactions, (2) major and/or frequent upper respiratory viral infections and fevers, (3) taste and appetite suppression, (4) growth suppression, (5) lethargy and depression, (6) diarrhea, and (7) offensive body odor. These symptoms are more often noted by the family and pediatrician than by the oncologist. They have not previously been associated with leukemia in terms of their having a common nutritional origin.
The occurrence of one or more of these symptoms is frequent enough in the year preceding the onset of ALL to suggest that there may be a nutritional linkage, or common denominator, between them individually and between them and leukemia. Obviously, they are not normally predictive of leukemia. In fact, many are typical of what has come to be considered as normal childhood problems that eventually go away with or without treatment, although nutritional deficits could still be causal.
Since no other etiology of leukemia exists, this backward-looking approach seemed to offer at least a chance to develop an hypothesis concerning the etiology of leukemia.
Since many of the classical symptoms of leukemia were known to result from an active disease, no rationale for their repeated study existed. These classical symptoms include anemia, ease of bruising, fever, nightsweats, splenic, liver and lymph gland enlargement, peripheral blasts, petechiae, bone or joint pain, and hemorrhage.
If leukemia is to be prevented or its incidence lessened, a better understanding of the role of individual nutrients in the etiology of pre-leukemia symptoms appeared to be necessary. If a role for a single nutrient could be found for each of the symptoms of pre-leukemia, leukemic cell involvement, and recovery, a major break-through in the prevention of childhood leukemia via nutritional means could eventually be forthcoming.
II. ZINC DEPLETION, THE COMMON DENOMINATOR IN THE PRE-LEUKEMIC CONDITION
In a direct review of over 10,000 medical journal and clinical nutrition journal articles published between 1976 and 1981, and review of computer searches of the world medical literature, only zinc deficiency was found to have a role in the occurrence of the seven pre-leukemic cells; and by reversing the zinc deficiency killing leukemic cells, reducing asparagine, and stimulating immunity to the leukemic cells. Several other nutrients had roles in one or another symptom or function, but only zinc was functional in each of them.
The following is a review of the role of zinc in the management and cause of the pre-leukemic symptoms. It is from the zinc perspective that many previously unrelated symptoms seem to share a common genesis. The role of zinc in leukemia and other activities is presented elsewhere within this review. The full role of zinc in human nutrition is outside of the scope of this review, and certain obvious roles of zinc such as its role in the male reproduction system are purposefully omitted.
Mast cells and basophils are commonly known to be the mediators of Type I allergy. Hayfever, food allergy, asthma, allergic croup, gastrointestinal allergy, and anaphylaxis are manifestations of Type I allergy. Allergic reactions result from the release of histamine, heparin, slow-reacting substance of anaphylaxis (SRS-A) and kinins from the cell's granules. The release, generally, is caused by a reaction of antigen with mast cells or basophils coated with IgE antibody. This reaction causes a degranulation of the cell's contents and active transport of the cell's contents through the cytoplasmic membrane of the cell. (Ref. 1, p. 329).
The granules of both basophils and mast cells also contain zinc ions (Ref. 2, p. 320). These ions stabilize the cell and prevent induced histamine and other component release from mast cells if sufficiently available. When released, zinc can contribute significantly to several immune reactions described in other parts of this review. It is believed that this effect of zinc is attributable to its action on the cell membrane. It has been speculated that zinc may form mercaptides with thiol groups of proteins, possibly linking to the phosphate moity of phospholipids or interaction with carboxyl groups of sialic acid or proteins on plasma membranes, resulting in a change of fluidity and stabilization of membranes (Ref. 3, p. 221; Ref. 71).
There are also several enzymes attached to the plasma membrane which control the structure of the membrane, and the activation of these enzymes may be controlled by zinc. Adenosietriphosphatase (ATPase) and phospholipase A2 are known to be inhibited by zinc, and this effect may explain immobilization of energy-dependent activity of plasma membrane or increased integrity of the membrane structure (Ref. 3, p. 221).
Several receptors at the plasmatic membrane presumably function as a gate for transmitting information to intracellular space. In the case of mast cells, histamine-releasing agents seem to work through specific receptors at the membrane. Masking of such receptor sites by membrane impermeable Zn:8-hydroxyquinolone would thus explain the inhibition of the release reaction (Ref. 3, pp. 221-222).
The role of Ca2+ in the function of cell microskeleton, represented by microtubules and microfiliments, has been well documented. The contractile elements of this system are in some way responsible for the mobility of microorganelles and transport of granules to the membrane as well as excitability of the plasma membrane itself. Since zinc is known to compete with calcium, it may thereby inhibit this effect of calcium (Ref. 3, pp. 221-222).
In addition to histamine's role as a mediator of Type I allergy, histamine also has direct T-cell immunosuppressive aspects which are discussed elsewhere in this review.
Inhibition of histamine release begins at about 10-6M concentration of zinc ions (in humans) and is maximum at 10-4M concentration (10 times the normal 10-5M concentration). Zinc is released with histamine (Refs. 73,74) and may have an antiviral function. Fifty mg zinc with each meal has been shown to be beneficial in the treatment of allergic diseases (urticaria and erythema multiforme) where zinc serum levels were low (65 mg dl)or 65% normal (Ref. 75).
It may very well be that the known zinc serum level reductions so often found in leukemic children are the cause of the severe allergy-like symptoms that precede leukemia. That they occur in children for as long as a year before leukemia occurs may result from a powerful LEM-like reaction and possibly the leukemia inducing agent (virus?) itself. Clearly, the release of histamine, unchecked by sufficient zinc ion concentration is immunosuppressive.
VIRAL AND TUMORAL IMMUNITY
The T-cell lymphocyte response is the basis of cellular mediated immunity (CMI). The CMI is vitally important in protection against virus, fungal and protozoan infections, as well as against malignant and autoimmune disease. Effector T-cells may be thought of as the immune system's "field commanders," responsible for the initiation and regulation of immune responses from other effector T-cells, suppressor T-cells (including cytotoxic natural killer cells), ▀ cells, and other white cells (Ref. 5). They also interact with these cells in numerous immunological events designed to present the best immune response. Antigen sensitized T-cells, upon second exposure to the antigen, transform to an activated form, lymphoblasts, which can directly lyse the antigen, or release soluble factors, lymphokines, which aid in the destruction of the target cell or antigen. Interferon is released upon exposure of T-cells to mitogens or specific antigens (Ref. 1, p. 302). Effector and suppressor T-cells may be distinguished from each other through their responses to mitogens.
A search was made for disease models having nutritional response to impaired cell mediated immunity. Genetic causes of impaired cell mediated immunity and congenital defects of CMI were reviewed and considered.
Vitamin A, B complex, and C, zinc, proteins and lithium were found to have a role in the nutrition and function of the CMI (Refs. 6,7,8,9). In nutritional deficiency, in general, there is often found significant immune system impairment. A reduced number of T-cells, an impairment of delayed hypersensitivity, an impairment of mitogen and antigen induced lymphocyte DNA synthesis, a reduction in soluble factors released, an increase in the number of null cells, a relative decreases in the T-cell/▀-cell ratio (with ▀-cells usually unchanged). increased IgE, lowered IgG, IgA and IgM, unchanged phagocytosis, depressed serum transferrin levels, decreased serum levels of most complement components and other immune system alterations are observed in various states of malnutrition. In mild under nutrition in children without growth retardation, alterations in immunity function are less frequent (Ref. 4).
No specific disease model was found in this study wherein the normal CMI response was depressed and could be normalized by restoration of a single nutrient except for zinc. This includes scurvy and Vitamin C. In fact, scurvy causes no characteristic change in the leukocytes at all (Ref. 1, p. 231). However, it has recently been found that Vitamin C and hyperthermia produce a modest enhancement of the immune response to influenza virus (Ref. 10).
Some examples: Thymic regrowth and cell mediated immune response after recovery from protein-energy malnutrition was observed not to take place until after a modest supplementation of zinc ( 2 mg zinc per kilogram of body weight was given (Ref. 7). Cell mediated immunity returns when zinc is administered in acrodermatitis enteropathica (Refs. 11,12). Depressed cell mediated immunity returns when zinc is administered in Down's Syndrome (Ref. 13). Down's Syndrome has a probability of leukemia 30 times normal, when unsupplemented (Ref. 1, p. 290). It remains to be determined if zinc will alter the leukemia rate in these children. In other conditions such as general malnutrition and parenteral nutrition, zinc restores depressed cell mediated immunity (Refs. 8,14,15,37).
Since the CMI response is also responsible for tumoral immunity, it becomes important to understand the stimulating effect of zinc on CMI in the presence of phytohemagglutinin (PHA) in vitro or antigens in vivo. Zinc has a specific mitogenic effect on PHA stimulated T-cell lymphocytes (Refs. 3,6,16,17). PHA is a specific effector T-cell mitogen vitro (Ref. 1, p. 307; Ref. 5). Lymphocytes from rats fed a diet high in zinc were most susceptible to PHA transformation. Within 3 days, zinc supplemented rats had twice the stimulation index of controls. Within 5 days, it was three times control. By 7 days it has returned to less than control (Ref. 6, p. 278). This suggested that zinc accelerates the proliferative response of effector T-cell lymphocytes which, in turn, could then accelerate and strengthen responses of antigen sensitized cytotoxic killer cells from the suppressor subset and other immune responses for the inactivation of viruses and tumors.
Plaque forming cell (PFC) responses to tumor cells in animals are significantly lower in zinc deficiency. A decrease in the number of helper or effector T-cells, or precursors of antibody forming cells or increased suppressor cell activity may be responsible for this observation (Ref. 16). Studies are needed to ascertain the role of supplemental zinc in reactivating T-cell lymphocyte response to tumors. However, it is known that zinc increases the number of effector T-cells.
It has been demonstrated that it is possible for the immune system to eliminate large established tumors in mice by infusion of sensitized T-cells from immune donors but only when the tumors grow in thymectimized and T-cell-depleted recipients. These and other similar findings strongly suggest that the failure of the immune system to reject the immunogenic tumor is the result of the generation of suppressor T-cells and not cytotoxic killer cells (Ref. 18).
Since the host immune response to a fetus is similar (or identical) to the host immune response to a tumor (Ref. 19), an effect of zinc in stimulating effector T-cell function against tumors (fetuses) may have already been observed in animal pregnancy. Zinc supplements (100 mg zinc sulfate three times daily) during the third trimester of pregnancy resulted in three pre-mature births and one still-birth in four consecutive subjects (Ref. 20). Other recent studies have presented data linking heightened suppressor cell function in human pregnancy (a known zinc deficient state) to lowered PFC response and splenic enlargement with suppressor cells. Similar PFC changes have been observed in animals under conditions of tumor growth (Ref. 21).
Histamine is known to activate suppressor T-cells and to suppress the PHA proliferative response of effector T-cells. A minimum of 2 hours contact with histamine is required in order to activate suppressor cells. Maximum suppressor activity occurs in 18-24 hours, and is not increased thereafter. The suppression is dose-dependent. At a histamine concentration of 10-3M to 10-4M the suppression is equivalent to that suppression obtainable with Con A (Ref. 42). It is well known that histamine mediates the allergic responses encountered in pre-leukemia as well as in other malignancies, atopic allergy, infections and upper respiratory viral infections. Consequently, zinc metabolism errors or gross zinc deficiency can directly damage effector T-cell responses to tumors, and indirectly damage effector T-cell responses to tumors through histamine inhibition of effector T-cells and activation of suppressor T-cells.
A number of chemically induced or transplanted animal tumors have been inhibited, prevented and/or eliminated by simultaneous administration of zinc. Woster found that it was necessary to administer zinc within two days of the administration of the tumor cells for zinc to be protective. Phillips and Sheridan have demonstrated that zinc injected intraperitoneally prevented tumor genesis in 50-70 percent of mice previously innoculated intraperitoneally with certain leukemic cell lines. Without zinc, all controls died from the same types of leukemic cells and dosage (Ref. 22, p. 206). According to Phillips, either zinc potentiated effector T-cell activity (specifically PFC function), or minimized the suppressor response, or induced T-cell immune interferon, or directly poisoned these cells or any combination thereof (Ref. 22,31).
Recent studies in human interferon production point out that lymphoblastic transformations of T-cells is a necessary prerequisite to T-cell immune interferon production (Ref. 23). Since other effector T-cell mitogens also induce interferon (Ref. 43), the mitogenic property of zinc on effector T-cells suggests that interferon production results. Zinc without viral antigens has been demonstrated not to stimulate interferon production (Ref. 31). Since there is a differential role for zinc between antigen and mitogen induced lymphokine production (Ref. l67) it is suspected that an antigen must be present before zinc can stimulate interferon production.
Several roles for zinc exist in the activation of T-cells. Zinc ions stimulate DNA synthesis of lymphocytes within a few days; at this time approximately 10%-40% of cells are transformed into lymphoblasts. Additionally zinc-8 hydroxyquinoline unsaturated complexes are stimulatory to animal lymphocyte mitosis, even though it is cytoplasmic membrane impermeable. Consequently at least two mechanisms exist for zinc to stimulate lymphocytes in some animal models (Ref. 6, p. 278).
In humans, one protein, transferrin, is vital to CMI in that only transferrin bound zinc is functional in the human T-cell lymphocyte. Since transferrin in the humanis only 30% iron saturated, substantial zinc transport capacity for immune function is normally available. Clearly, a nutritional deficit that induces a loss or significant reduction in transferrin synthesis would cause both anemia and primary immunodeficiency (Ref. 22). Interferon and transferrin concentrations are reduced in those nutritional deficiencies, such as zinc, that interfere with protein synthesis (Ref. 66).
In leukemia, transferrin levels are often very low. Giving zinc raises the transferrin serum level with a concurrent increase in lymphocyte transformation. Adding transferrin by transfusion results in stable and normalized transferrin serum levels but only when given in massive doses (20-30 mg/kg body weight/day) over a 14-day period. Lesser doses are rapidly eliminated from the blood, possibly by a LEM-like reaction where the liver removes zinc from the blood. Again, lymphocyte transformation is increased. In 1953 some remissions from acute lymphocytic leukemia occurred after giving large doses of zinc and/or zinc transferrin, although the number of subjects was too small to prove anything conclusive. During the course of treatment a simultaneous tendency to normalization of the number of blood cells and maturation of the peripheral blood also occurred (Ref. 44).
Unfortunately, T-cell lymphocyte count, activity and function in infants, early childhood and in older people may be inadequate or absent. Alternatively, either cytotoxic or suppressor subset functions might be too low or too high resulting in imbalanced T-cell function, and predisposition to either immunodeficiency or auto-immune disease (Ref. 5).
According to Robert Good, T-cell count and function change in humans after a period of zinc deprivation resulting in thymic involution. A dramatic breakdown in immunity follows, particularly helper T-cell and killer T-cell function as well as plaque-forming (PFC) response to tumors. Other antibody-related changes also occur. The unique sensitivity of the human thymus to zinc depletion may be related to the fact that terminal deoxyribonucleotidyl transferase is a zinc containing enzyme which is only found in the thymus and immature thymocytes. Zinc deficiency also causes other thymic related changes including a drastic reduction in a hormone (FTS) needed in the differentiation of precursor cells into ě-positive lymphocytes (Ref. 46).
Zinc can be used to improve age-associated immune dysfunction. When oral zinc supplementation (440 mg zinc sulfate) was given to institutionalized healthy people over 70 years old, there was significant improvement in the number of circulating T-cell lymphocytes, delayed cutaneous hypersensitivity reactions and immunoglobulin G (IgG) antibody response. Zinc had no effect on the number of total circulating leukocytes or lymphocytes or on the in vitro lymphocyte response to three mitogens including PHA, Con A, or PWM) (Ref. 68). Malignant disorders are often considered diseases of aging. It is highly probable that administration of zinc to the elderly (or any age group) who demonstrate reduced T-cell function will result in increased or even normalized resistance to tumor formation.
Obesity as well as nutritional deficiency in humans can adversely affect CMI and other immunological functions. In one test, zinc therapy for four weeks improved immunological responses in the subjects (Ref. 70). Increased malignancy rates in obesity have been observed. It seems probable that zinc can be effective in reducing the malignancy rate in the obese population.
Since zinc is necessary for thymic function and effector T-cell function and effector T-cell function is necessary for many other immune functions, it is now somewhat clearer why zinc nutrition is important to immunological health. It is noteworthy to observe that the new-born human infant receives 70-900 mmg zinc per 100 gm colostrum, thus significantly changing the zinc/copper ratio and activating the infant's primary immune system (Ref. 29, p. 30). Perhaps zinc is truly nature's immune system switch.
In addition to zinc stimulation of effector T-cells, lithium is now being used to significantly minimize the leukocyte immunosuppression caused by some cancer chemotherapy drugs with a ten-fold reduction in infection, and even greater reduction in mortality (Ref. 24). Mixtures of lithium, zinc and calcium have been shown to stimulate lymphocyte transformation to levels observed for lectin stimulation (Ref. 9). Lithium appears useful in treating children with certain kinds of chronic neutropenia (Ref. 69).
Although zinc is necessary for interferon production, extremely high amounts of zinc (10- 1M and above) result in the prevention of interferon release when induced by the Sendai virus (Ref. 80). It is suggested that the zinc interferes with the proteolytic cleavage of interferon before it is secreted. However, the possibility of zinc inhibiting viral polypeptide cleavage was not discounted. No change in interferon secretion was noted (either elevated or reduced) at zinc ion concentrations less than 10-2M (Ref. 80).
BODY ODOR -- FREE ASPARAGINE?
On occasion a strong and offensive body odor is emitted from a person prior to diagnosis of acute lymphocytic leukemia. The odor is thought to be that of an accumulation of free asparagine which is an essential amino acid for malignant cells by a nonessential amino acid for normal cells.
In experiments to ascertain whether zinc played a role in nucleic acid metabolism and protein synthesis, it was shown that for the microorganism EUGLENA GRACILIS, zinc deficiency would result in a marked decrease in protein and RNA content and an increase in free amino acids. The increase of amino acids is largely accounted for by glutamine and asparagine. The accumulation of these two amino acids suggest that they represent storage of excess nitrogen resulting from impaired protein synthesis. Similar results have been observed in plants (Ref. 6, p. 109).
Assuming that the molecular nature of unique biological activities is the same in all biological species, then zinc deficiency could also result in an accumulation of free asparagine in humans, and may explain the presence of high levels of free asparagine in pre-leukemia and leukemia.
L-Asparagine synthetase has been shown to be responsible for the resistance to L-Asparaginase in Acute Lymphocytic Leukemia. It is also present in many experimental tumors and in the normal mammalian pancreas. In one experiment, L-Asparagine synthetase was 90%-100% inhibited by zinc chloride at a 1 milliM concentration in vitro. Tests indicated that zinc interacted at the L-glutamine site on the enzyme. In vivo zinc experiments failed to affect the concentration of L-Asparagine although the test mice revealed necrotizing pancreatitis at a single dose rate of 100 mg/kg or when given daily at a dose rate of 20 mg/kg (Ref. 48). Other studies, primarily by Jerry Phillips, fail to substantiate the above statement related to necrotizing pancreatitis at the stated doses (Ref. 31). This important experiment needs to be repeated.
Growth suppression, decreased weight, skin changes, mental lethargy, apathy, depression, irritability, excessive fatigue, poor appetite, smell and taste alterations, palpable liver and spleen, thymic atrophy, diarrhea, malabsorption, steatorrhea and ophthalmic signs are a few of the other clinical manifestations of zinc deficiency (Ref. 25; 26, p. 137). Most if not all of these symptoms have been observed in pre leukemia. No more than one or two may be observed in any one person or at any single time. In effect they can hardly be distinguished from many other routine childhood illnesses, and are not direct evidence of zinc deficiency.
The laboratory criteria for the diagnosis of zinc deficiency are not well established either. The response to zinc therapy is probably the most reliable index for making a diagnosis when considering the cause of such symptoms (Ref. 25). Zinc serum levels have not been shown to always be a reliable indicator of zinc bioavailability. In fact, cases of acrodermatitis enteropathica, a lethal zinc deficiency disease, have been found with much higher than normal zinc serum levels, which returned to normal upon zinc supplementation (Ref. 11,27).
Symptoms found in zinc deficiency may also be caused by enzyme or cellular malfunctions and by nucleic acid malfunctions. Over 90 enzymes have been identified wherein zinc is a necessary constituent, with 45 being involved in basic cellular reproduction (Ref. 46). Zinc functions in these enzymes by maintaining spatial and configurational relationships (Ref. 26, p. 136). A number of these enzymes such as alkaline phosphatase are involved in cellular growth and are sensitive to zinc deficiency.
A few examples of zinc enzymes include: alcohol dehydrogenase, RNA polymerase, DNA polymerase, alkaline phosphatase, carboxypeptidase A and B, dipeptidase, aldolase, carbonic anhydrase, pyruvate carboxylase, and superoxide dismutase (Ref. 3,6,15).
The precise relation of zinc to zinc deficiency symptoms remains to be determined in most cases.
Growth related problems and fatigue could be related to the role of zinc in protein synthesis, enzymes, and absorption (Ref. 15). Mental and emotional problems could be related to zinc's role with histamine as a neurotransmitter in the hippocampusmossy fiber structure of the brain (Ref. 29, p. 10). A palpable spleen might be related to zinc deficiency induced increase in spleen seeking suppressor T-cell lymphocytes (Ref. 21). Thymic atrophy could result due to the basic nutritional need for zinc by the thymus (Ref. 7,46). Zinc is a functional part of the retina and is helpful in treating cataracts of the elderly (Ref. 20). Acne and other skin problems can be a zinc deficiency. Zinc is very helpful in alleviating acne. Diaper rash often dramatically responds to zinc oxide lotion (Ref. 20).
As more information about the clinical hallmarks of the zinc deficiency syndrome is understood, the following are currently believed to be markers of zinc deficiency: hypozincemia, iron deficiency anemia, hepatosplenomegaly, growth retardation, arrested sexual maturation, partial adrenal insufficiency, anorexia, dryness and hyper pigmentation of the skin, impaired taste and smell acuity, delayed wound healing, sub optimal growth, poor appetite, pica, impaired immune response. Diseases that are known to be associated with zinc deficiency include malignancy and many other diseases (Ref. 78).
III. ZINC DEPLETION, A STAGE FOR LEUKEMIA?
The role of zinc deficiency or improper zinc metabolism has been established as possibly being causal in the conditions found prior to the actual development of ALL, and suggests that zinc depletion may present a stage for leukemia, by decreasing natural resistance to leukemia, by increasing the amount of free asparagine, by increasing corticosteroid levels, and by allowing lymphocyte genetic requirements for zinc to go unmet. Zinc deficiency in the leukemic process itself can also be demonstrated.
ZINC CONTENT OF LEUKEMIC BLOOD
Leukemic cells contain only about 10% of the zinc contained in normal lymphocytes (Ref. 1, p. 201). Plasma zinc concentrations are lower and plasma copper concentrations are higher in children with untreated ALL than in the same children after successful treatment or healthy children (Ref. 22,79). Zinc transferrin is also low in many cases of leukemia (Ref. 44). In one case of acute myelogeneous leukemia, zinc deficiency was so severe that acquired acrodermatitis enteropathica developed (Ref. 30). In several cases of ALL, zinc deficiency symptoms developed. Remarkably rapid elimination of zinc deficiency symptoms and greatly increased tolerance to the chemotherapy occurred with zinc (Ref. 62). The DNA of CCRF-CEM human leukemia cells contain one-fourth of the zinc of normal lymphocyte DNA. RNA from leukemic cells, however, contained nearly four times the zinc of control RNA. Histone, from leukemic cells, which is known to be involved in the regulation of gene expression, only contain one-fourth of the zinc content as is contained in control histone. Consequently, zinc depleted histone fractions could alter the interaction of histones with DNA and as a consequence alter gene activity (Ref. 22, p. 204). The nucleus of human chronic lymphocytic leukemia cells contain only one-third the zinc of normal cells. The cytoplasm of human chronic lymphocytic leukemia cells contain only one-third to one-fifth the zinc of normal cells. Phillips found that leukemic lymphocytes incorporate transferrin bound zinc more slowly and to a lesser extent than do normal lymphocytes. In addition, he found that normal lymphocytes respond to increased intracellular zinc by synthesizing a low molecular weight protein, possibly a metallothionein, while lymphocytes from donors with chronic lymphocytic leukemia fail to synthesize this intracellular zinc-binding protein (Ref. 22, p. 204). It is well known that excessive zinc excretion and low level of serum zinc occur in leukemia.
Zinc is necessary for proper regulation of prostaglandins as well as being antagonistic to calcium. In leukemia, and malignancy in general, cellular prostaglandin levels are distorted resulting in cell membrane fluidity, rigidity or other functional alterations. Calcium metabolism is unregulated, and no control over cytoplasm calcium can be established thus resulting in undesired cellular division. These differences along with impaired primary immune functions and other biological activities are suggested to be reversible or controllable when certain nutrients including zinc and gamma linolinic acid necessary for prostaglandin and calcium regulation are supplemented in a sufficient amount and in a biochemically available form (Ref. 72,73). The only known exogenous source of gamma linolinic acid is the evening primrose oil.
GENETICS AND ZINC
Zinc is necessary for all growth. In is absence all growth, including malignant growth, is not possible (Ref. 63).
As early as 1949, differences in zinc metabolism of normal and leukemic lymphocytes first gave rise to the postulate by Vallee and Gibson that the disturbance of a zinc-dependent enzyme is critical in the patho-physiology of myelogenous and lymphatic leukemia as well as lymphoma, Hodgkin's disease and multiple myeloma (Ref. 6,63). Data obtained since 1949 bear out the 1949 postulate that zinc is involved in nucleic acid metabolism and that zinc deficiency bears importantly on the lesions observed in leukemia and other conditions (Ref. 6,63). Experiments using ethylenediamine tetraacetate (EDTA) and other metal chelators to chelate metals within DNA and DNA polymerase result in functional inhibition of their activity which can be reversed only by adding Zn2+ in the growth medium. The same results occur for terminal deoxynucleotidyl transferase, DNA-dependent RNA polymerase and thimidine kinase from several species (Ref. 6, p. 246; Ref. 63). Direct evidence that the RNA-dependent DNA polymerase--a reverse transcriptase--from avian myeloblastosis virus is a zinc metalloenzyme has been obtained. Zinc is the only mineral present in this enzyme (Ref. 3, p. 119; Ref. 64,65). Inhibition of RNA-dependent DNA polymerase by zinc chelation brings about both an instantaneous reversible inhibition and a time-dependent irreversible inhibition (Ref. 6, p. 247). Zinc also regulates the activity of RNase, thus the catabolism of RNA also appears to be zinc dependent (Ref. 3, p. 223).
Studies such as these establish the importance of the role of zinc in the formation of DNA from RNA templates and extend previous findings that zinc is necessary in the formation of RNA and DNA from DNA templates.
It is still not clear at all why zinc deficiency in genetic material causes such molecular instability and dysfunction. There must be a relationship between zinc deprivation and the malfunction of molecular systems based upon zinc metalloenzymes (Ref. 6, p. 247).
In terms of enzyme sensitivity to zinc deficiency three enzymes -- alkaline phosphatase, carboxydeptidase and thimidine kinase -- appear to be most sensitive to zinc restriction in that their activities are affected adversely within three to six days of institution of a zinc-deficient diet in experimental animals (Ref. 3, p. 223).
Additionally, it has been demonstrated that zinc may be necessary for all phases of cell growth. Zinc was required for cells to pass from the G1 phase into S, from S to G2 and from G2 to mitosis (Ref. 3, pp. 115,217; Ref. 22, p. 205). It is tempting to suggest that the proliferation of blasts in leukemia is solely due to those cells being stuck in an early stage of development simply due to an intracellular deficiency of zinc or zinc metabolism errors. However, in zinc deprived rats the mast cell population of the tibia bone marrow became increasingly higher than in controls. It was also noted that zinc deficiency was responsible for the accumulation of mast cells which were incapable of completing their maturation. In view of the general growth depressing effects of zinc deficiency, it is difficult to imagine the accumulation of mast cells in the bone marrow as the result of any known growth stimulating phenomena. It was suggested as being possible to consider zinc as a factor in the differentiation and release of the mast cells (Ref. 32).
Upon consideration of the human leukocyte antigen (HLA) system, the amelioration of some diseases related to A1 and A2 have been demonstrated to be possible with zinc. Hayfever, and asthma (A1) and primary immunodeficiency (A2) can be ameliorated by zinc when supplemented at the rate of 1-2 mg/pound/day . Recurrent Herpes (A1) can be eliminated with topical zinc application. If the genetic markers A1 and A2 denote a genetic need for increased dietary zinc, then a number of other diverse HLA-A1 and A2 associated diseases (and perhaps A3 and A10 diseases) might be ameliorated by zinc in much the same way as pernicious anemia (B7) can be ameliorated by supplemental Vitamin B-12.
IV. NUTRIENT / CHEMOTHERAPY INTERACTIONS
As stated in Part I, a major reason for conducting this review was to determine if any supplemental nutrient could positively influence the chemotherapeutic agents used in CCG protocol 161 regimen 2. In this protocol, predisone, vincristine, L-asparaginase, and intrathecal methotrexate are used for remission induction followed by 2400 rads cranial radiation. Maintenance therapy calls for use of vincristine and predisone on a monthly "pulse" basis, methotrexate weekly and 6-mercaptopurine daily.
This protocol results in the depletion or inactivation of niacin, vitamins B-6, C, D, and folic acid, as well as zinc, calcium, potassium and nitrogen. Of these only folic acid is known to be intentionally depleted. Replacement of the other nutrients may be beneficial to normal health, however only replacement of zinc had even a theoretical possibility of influencing the performance of any of the drugs used in this protocol, according to the literature reviewed.
Zinc may be important as a dietary supplement at the rate of 1 - 1 1/2 milligram zinc per pound of body weight in the treatment of ALL using protocols containing L-asparaginase.
L-asparaginase contains the enzyme L-asparagine amidohydrolase which destroys the amino acid asparagine. Leukemic cells are dependent upon an exogenous source of asparagine for survival. Normal cells, however, are able to synthesize asparagine and are thus affected less by the rapid depletion produced by L-asparaginase. Depletion of asparagine is a unique approach to therapy of ALL based upon a clear metabolic difference between leukemic lymphocytes and normal lymphocytes (Ref. 34). Linus Pauling writes in his book "VITAMIN C AND CANCER" about L-asparaginase: "Theoretically the perfect anti-cancer drug, exploiting one clear biochemical dissimilarity between normal and malignant cells."
It has been demonstrated that zinc deficiency in bacteria and plants produces accumulations of the free amino acid asparagine, which is believed to represent storage of excess nitrogen resulting from impaired protein synthesis (Ref. 6).
Since many similarities at the molecular level exist between the species; it is reasonable to suggest, at least in the absence of clear proof to the contrary, that zinc deficiency induces free asparagine accumulation in human tissue. Zinc deficiency is known to exist in leukemia. The result is that this mineral deficiency, theoretically at least, competes with L-asparaginase by stimulating L-asparagine synthetase thus replenishing free asparagine. L-asparaginase is only effective when new asparagine is not being released, or is being released at a rate commensurate with the dose, frequency and duration of therapy with L-asparaginase.
Consequently, the supplementation of zinc should theoretically improve the effectiveness of L-asparaginase in the management of malignant disorders even though in vivo animal studies disagree (Ref. l48).
In the case of the child with ALL where 50 mg. of zinc was given daily and coterminous with L-asparaginase, bone marrow blast count went from 95+% to an observed count of zero blasts in less than 14 days. This is the only known humans case of augmentation of L-asparaginase with zinc. Since bone marrow improvements normally obtained by 85-90% of patients with ALL on similar protocols still contain 3-5% blasts after 30 days in a M-1 remission, these results, as far as can be determined, are completely unique in the management of ALL. It is also significant since the rate in which a remission is obtained, as well as the reduction in blast count, has been demonstrated to be related to the propensity to relapse.
L-asparaginase has been observed to be highly toxic to the liver and capable of inducing anaphylactic shock (Ref. 34). Zinc, to the contrary, has been shown to have a protective influence from toxic substances, such as carbon tetrachloride, on the liver and reduces or prevents anaphylactic shock through its mast cell regulatory role in Type I allergy (Ref. 3, p. 221) and its stabilizing effect on all cell plasma membranes. No adverse reactions of any kind were noted in the first test of zinc as an adjunct to L-asparaginase in the 3-year-old girl. Additionally, in the absence of information in the literature to indicate harm by zinc, other tests of zinc in the amplification of the effectiveness of L-asparaginase seem both reasonable and necessary, if not given in great excess in order to eliminate or minimize pancreatic injury.
NOTE: Consider L-asparaginase as "a mop to pick up asparagine from a leaky faucet, while zinc turns off the faucet!" This combination in some form is probably the cure for all cancers, although tumor death products may be toxic to normal cells.
The action of predisone against leukemic lymphocytes involves the diminution of glucose and amino acid transport into the cell, phosphorylation and thymidine incorporation. So long as the cell line retains the cytoplasmic receptors for glucocorticoids, the cell is susceptible to cytolysis in response to steroids (Ref. 1, p. 1652). Corticosteroids increase urinary excretion of zinc and decrease serum zinc (Ref. 26, p. 461) (Important!) Hyperfunction of the adrenal cortex, with a release of cortisone accompanies zinc deficiency (Ref. 26, pp. 137,670). It is known that catabolism due to infection results in glucocorticoid release and negative zinc balances (Ref. 26, p. 697). In protein-energy malnutrition of children, thymic atrophy of stress is believed to be mediated by high levels of circulating corticosteroids. Zinc supplementation causes thymic regrowth in children recovering from protein-energy malnutrition, whereas a normal high energy diet does not cause thymic regrowth. Altering the corticosteroid/zinc relationship by supplementing zinc relieved cell mediated immunity and humoral immunity problems in these children, as zinc also stimulates both lymphocyte function and cell mediated immunity (Ref. 7). Excessive zinc excretion occurs in leukemia (Ref. 47) suggesting high corticosteroid levels and consequent immunosuppression.
In the case of the child who was administered zinc in conjunction with predisone, no adverse reactions were encountered. Total white blood cell count averaged 4000/mm3 and varied between 2000/mm3 and 7000/mm3 on infrequent occasions. Absolute lymphocyte count averaged 1400/mm3 until chemotherapy was increased due to weight and height gain. Afterwards, ALC remained at 1000/mm3 or less. Moonface appearance and obesity normally found with use of predisone were absent. Immunity to diseases appeared normal in that the incidence of infection became much lower after initiation of chemotherapy with zinc than during an equivalent period prior to diagnosis. Atypical or activated lymphocytes were noted in 12% of the bi-weekly blood tests. Growth was accelerated after initiation of chemotherapy and zinc. A "catch-up" growth occurred from preleukemic height and weight of 28% and 5% respectively to 50% and 50% respectively after one year of treatment for ALL and use of zinc throughout the third year, growth has remained at the 50% level for both height and weight with only minor variations. In general the child enjoys excellent health and is very strong.
In studying the immunostimulatory effect of zinc in patients with ALL in Poland, researchers in 1978 added to the above observations. They found that, with drug protocols very similar to CCG 161 that the effect of zinc was statistically significant in enhancing T-cell mediated immunity, raising TEa5' percentage from 22.3 to 32.4 and absolute number of TEt60' from 338.8 to 517.2. No change in IgG, IgA, IgM or total gamma globulins occurred. A slight decrease in granulocyte count was the only adverse side effect noted. And it was not considered statistically significant (Ref. 45).
Dental caries are predicted in zinc deficiency (Ref. 35). Since zinc deficiency is often caused by use of predisone it is often found that dental caries accompany ALL while undergoing treatment with predisone. In this case, no dental caries formed, and dental health remained excellent, with 4 adult teeth forming normally within the 3 years of treatment.
Bone marrow blast count has remained completely stable at 0.2% for three years of therapy. During a one-month period after 24 months of therapy when therapy was discontinued in order to administer chicken-pox vaccine, bone marrow blast count only rose to 2%, and then returned to 0.2% upon resumption of chemotherapy.
V. ZINC AS A VIRUS, AND RNA TUMOR VIRUS REPLICATION INHIBITOR
Experiments as early as 1973 by Bruce Korant have clearly demonstrated the ability of zinc to act as a replication inhibitor for certain viruses. In the rhinoviruses, zinc's effects are to block polypeptide cleavage. Addition of only 0.2mM zinc prevents post-translational cleavages and causes the accumulation of a set of large precursor polypeptides. Different cleavages were sensitive to different concentrations of zinc, and progressively larger polypeptides could be accumulated by increasing the zinc concentration. The addition of zinc at any time during viral replication immediately inhibited further formation of infectious virons. A number of other metals were also tested but only zinc displayed antiviral activity in non-toxic concentrations. Eight out of nine rhinoviruses tested were sensitive to zinc at 0.1mM concentrations. Only rhinovirus type 5 was resistant (Ref. 6, 49). Added zinc is bound to capsids of rhinoviruses and prevents them from forming crystals. Zinc complexes with rhinovirus coat proteins and alters them so that they cannot function as substrates for proteases or as reactants in the assembly of virus particles (Ref. 50). The zinc ion is an inhibitor of virus production and blocks protein cleavage of rhinovirus, enterovirus, and cardiovirus precursors. Zinc ion blocks viral maturation of coxsackievirus. If zinc ions were present at the start of rhinovirus infection (in vitro) the virus could do little harm to cellular translation, thus host protein synthesis was spared if viral proteins were not synthesized and normally processed (Ref. 51, pp. 149-173). Many other viruses, including Herpes Simplex 1 and 2, encephalomyocarditis, foot-and-mouth, enterovirus 70, vaccinia and some other viruses have also been demonstrated in vitro and IN VIVO to be highly susceptible to destruction by zinc at non-toxic levels (Refs. 52,53,54,55,57,57,58,59,60,61,81). Korant, in addition, indicates that recent evidence for polypeptide cleavages during the replication of bacteriophages, and many animal viruses including RNA tumor viruses suggests a role for protease inhibitors, including zinc, in blocking certain stages of replication of many viruses (Ref. 49).
Observing that zinc inhibits the formation of tumors in animals and kills human leukemia (ALL) cells with other metal containing drugs such as CIS-platinum it is plausible to suggest that these cells were driven by RNA-tumor viruses that were controllable by zinc.
It is well known that viruses cause immunosuppression of their host in order for them to survive. Perhaps the RNA tumor virus causes the long term depletion of serum zinc in a manner similar to that resulting from bacterial infections or endotoxin reactions involving LEM and the liver. If that occurs, zinc depletion could result in long lasting immunosuppression favorable to the survival of zinc intolerant viruses such as the proposed RNA-tumor viruses. Fever is often associated with pre leukemia, and may indicate a period of time consistent with LEM production as a precursor event to frank leukemia. Administration of aspirin at the time of this type of fever could stimulate viral proliferation through increased immunosuppression, and could theoretically promote leukemia.
Additional evidence has been acquired that zinc can control virus activated tumor cells in that SV40-transformed human cells fail to grow in zinc concentrations which permit normal human fibroblasts to proliferate (2-3 x 10-4M. The only difference between the cells was viral infection by an oncogenic virus (Ref. 76).
Structural protein synthesis in the avian myeloblastosis virus have been shown to be preventable by exposure of intact cells to 10mM (10-2M) concentrations of zinc ions (Ref. 81) which is 100 times the concentrations necessary for control of rhinoviruses.
VI. ZINC IN RELATED ACTIVITIES
Zinc is a vital constituent of red blood cells. Red blood cells contain 6 to 8 times the amount of zinc as blood plasma, which is around 100 mg/dl (microgram/deciliter) (Ref. 16, p. 136). Most (75%-85%) of zinc in the blood is associated with carbonic anhydrase of the erythocytes (Ref. 20, p. 61). Zinc inhibits the formation and transformation of red blood cells into ghosts by certain hemolytic reactions of the complement system (C-9) (Ref. 36), while most zinc in cells is used to stabilize cell plasma membranes against viral infection, toxins, amd complement.
Only platelets in the human require more zinc than mast cells or basophils (Ref. 6).
White blood cells contain up to 25 times the amount of zinc in the serum. Mast cells and basophils contain extremely high amounts of zinc, being found in granules with histamine. Zinc inhibits macrophage mobility and phagocyte activity yet potentiates macrophage viability. Zinc deficiency results in maximum macrophage mobility. The effects are reversible and are believed to be due to a role of zinc on the cell's membrane (Ref. 6, p. 271). The overall regulatory control of zinc blood level is by the liver. Certain soluble factors, called leukocytic endogenous mediators (LEM), are released by activated leukocytes or macrophages during an acute inflammation of a bacterial origin or endotoxemia (Ref. 6, p. 93). They cause a sequestering of plasma zinc and iron by the liver within hours, accompanied by a potentiation of phagocytic function even when zinc is given at the 1-2 mg zinc/pound rates. An endogenous pyrogen (EP) is also released by phagocytizing white cells at the same time with a resultant increase in body temperature (Ref. 3, p. 99). Hyperthermia has been shown to potentiate the immune response (Ref. 10). It may be that the sequestering of zinc by the liver for protracted periods in bacterial infections could result in thymic atrophy and diminished T-cell function and count.
A significant fall in plasma zinc levels is noted in the third trimester of human pregnancy (Ref. 20, p. 63). Similar plasma zinc level reductions occur in malignant disorders. A triple purpose may be served by these changes: (1) fetal or tumoral uptake of zinc occurs, (2) diminished cell mediated immunity to the fetus or tumor (particularly PFC) occurs, and (3) leukocyte mobility enhancement occurs (Refs. 19,21).
Zinc may be sequestered by tumors from body stores, primarily the liver and bone, to fulfill their metabolic needs (Ref. 22, pp. 205-207). A consequent and deepened immunosuppression may occur if accompanied by an inadequate dietary intake of zinc. Tumor growth rate has not yet been shown to be accelerated when zinc is supplemented sufficiently to meet other body requirements such as T-cell and thymic requirements.
It has long been known that intestinal zinc and iron absorption is reduced in bacterial infections and endotoxemia presumably to simplify the function of the liver in starving the bacteria. Intestinal zinc absorption is enhanced in many but not all viral infections, presumably to impede viral growth.
Zinc aids in Vitamin A absorption. Vitamin A deficiency has been liked to malignant disorders. Could increased zinc intake in the general population aid in raising Vitamin A serum levels and reduce the cancer rate?
VII. SOURCES OF ZINC DEFICIENCY
Zinc as a trace mineral is second only to iron in abundance in humans. Its role in human metabolism is not yet totally known. Even the mechanism of zinc absorption is poorly understood. Zinc deficiency to the T-cell lymphocyte system and thymus may occur from a number of sources including inadequate dietary intake, faulty absorption across the intestinal mucosal membrane, inadequate or faulty albumen binding, inadequate cellular uptake, competition from other metals such as calcium, dietary chelation by phylates, from whole wheat and other dietary fiber, excessive soy bean intake, diarrhea, inadequate pancreatic function, faulty transferrin synthesis, and loss through catabolism from stress and infection (Refs. 3,6,15).
Low consumption of animal protein, geophagia, parasitic infestation, hemolysis, blood loss, high intake of dietary fiber, alcoholism, liver disease, malabsorption, renal diseases, burns, pregnancy, oral contraceptives, penicillamine therapy, poor appetite, chronic debilitation, Crohn's disease, cystic fibrosis, sickle cell anemia, malignancy, sweating, excessive consumption of food products process with EDTA or other metal chelators (used to prevent spoilage), poisoning by heavy metals such as lead and cadmium, and starvation are often accompanied by zinc deficiency (Refs. 3,6,15). In many other diseases zinc deficiency occurs for various reasons. Some are mentioned elsewhere in this report.
One writer found that it was difficult to find a stimulus to zinc absorption. Zinc is primarily absorbed and excreted through the intestines (Ref. 6). Increased urinary zinc excretion occurs as a consequence of a number of conditions including leukemia and other malignancies, starvation and surgery. It has been suggested that urinary zinc may provide an index by which to measure muscle catabolism (Ref. 26, p. 137).
Surgery has been shown to occasionally cause a permanent disturbance to zinc metabolism, unless 1 to 5 mg zinc/pound body weight is administered during and after (several days to several months) healing process. (Ref. 46).
In the case of growing children, competition for zinc is so intense and the opportunities for zinc deficiency so numerous that normal dietary zinc intake may be quite inadequate to supply all of the growing child's needs (Ref. 3, p. 202; Ref. 6, p. 30). The result being that faulty cell mediated immunity and excessive mast cell degranulation occur with an increase in viral illnesses, allergy, and malignancy, along with failure of other zinc dependent functions such as growth.
Still, no specific zinc linkage has been established that actually explains the occurrence of malignant transformations. However, it would be of interest to conduct studies using low level radiation on normal blast cells in vitro deprived of zinc transferrin compared with cells replete with zinc transferrin. Such studies have not been done although a similar study with no direct attention to zinc bioavailability using carefully nourished mouse fibroblasts found an extraordinarily higher cell transformation rate than had ever been previously expected from low level dental and medical diagnostic X-rays. One out of every 10,000 cells was malignantly transformed (Ref. 41). It is important to know if any washing was done with a metal chelator such as EDTA. If so, the zinc in the genetic material could have been so depleted so as to allow the cells to be defenseless against cellular transformation induced by low level radiation or other ionizing sources. This important experiment should be repeated paying careful attention to the role of zinc in the genetics of the cells.
VIII. THE TEXAS COLD CURE EXPERIMENT (PRE CLINICAL TRIAL ANECDOTAL EVIDENCE)
The Texas Cold Cure Experiment was an informal field study conducted during 1979, 1980 and 1981. It involved the use of zinc gluconate in the experimental treatment of common colds, allergic rhinitis, bronchial asthma, croup, food allergy and gastrointestinal allergy in field environments. The experiments were primarily conducted to ascertain if the role of zinc in normal health could suggest whether or not abnormal zinc metabolism could cause symptoms noted in pre leukemia and active leukemia. In other words, could these symptoms be reversed by additional zinc, and if so what significance do the findings have for the treatment of leukemia, and can additional zinc benefit the person with leukemia. Although the answers still need definition, a trend is clear. All experiments were uncontrolled but used the individual's previous health history and results of repeated trials with and without zinc to reduce the possibility of faulty observations.
The theoretical basis for the experiment is found in the preceding parts of this review. Briefly stated, zinc can prevent the abnormal release of histamine and other mast cell constituents, can retard suppressor cell function where excessive, can stimulate effector T-cell function and effector T-cell mitosis, and can have direct and anti-viral functions.
Zinc gluconate was used in preference to zinc sulfate since it was observed to cause less or no gastric disturbance in the dosages used. Zinc gluconate tablets with no sweeteners were also dissolved in the mouth as throat lozenges.
No significant toxicity has been demonstrated in humans at the dosages used in these experiments. Major toxicity symptoms can occur at doses in excess of 15 grams per day. Zinc is nonaccumulative. Zinc has been observed to be lethal at a single dose of 45 grams. Symptoms of long term zinc toxicity in humans include drowsiness, lethargy, increased serum lipase and amylase levels, vomiting, dehydration, electrolyte imbalance, abdominal pain, nausea, dizziness, muscular incoordination, and acute renal failure (Ref. 6, p. 17) and probably necrotizing pancreatitis.
Since very high levels of long term zinc administration can interfere with absorption of copper, manganese, selenium, iron and other minerals, and also necessitates higher Vitamin A intake, recommendations for a mild supplementation of these nutrients were also made.
Pregnant women and those who were medically immunosuppressed to prevent host-versus-grant disease were considered to have purposefully abnormal zinc metabolism and were not allowed to participate in the experiments. Theoretically zinc at these dosages could reinstate their immunity with the potential of abortion or host-versus-graft disease.
The lack of severe toxicity of zinc gluconate specifically has been observed in a case where a young woman ingested between 440 and 5700 mg zinc every day for 4 months. The most evident clinical changes were severe anemia, neutropenia, a ten-fold zinc serum level and a one-tenth copper serum level. Complete recovery occurred with withdrawal of zinc and supplementation of 2 mg copper/daily (Ref. 82). The woman ingested the zinc in split doses each two hours.
Theoretically zinc should prevent the release of histamine from mast cells and basophils. The amount needed at the beginning of the experiment was unknown. After repeated early trials, it was generally found that 1/2 - 2 mg zinc per pound of body weight in any age group was adequate for the improved management of any allergic symptom. The time for management of symptoms to occur varied from minutes for post nasal drainage to months for food allergies. Finding a correct dosage was slightly individualistic, and the response time was quite individualistic.
In general, symptoms of nasal rhinitis, including fatigue, irritability, depression, blocked Eustachian tubes, inflammation of tonsils, excessive nasal congestion, nasal drainage, post nasal drainage, coughing, sleep disturbances, headaches and sore throats could be eliminated or greatly relieved so long as the zinc therapy was maintained in most of the experimental trials.
It was found that the dose-response was non-linear with limited or no benefit at zinc intake just under the effective dose. It may be that this effect results from the competition of the zinc transport ligand and mucosal metallothionein synthesis in the intestinal lumen. Such a mechanism could be easily overcome at high levels of zinc intake with picolinic acid and in these cases metallothionein synthesis may be induced in the liver where excess zinc is either bound there or alternatively by individual cells (Ref. 15, p. 1262). The following are several examples.
One adult female subject had such a chronic and severe atopic nasal rhinitis with post nasal drainage that she could not sleep in the normal reclining position. Under her doctor's orders she sat upright strapped into a chair to sleep in order to prevent drowning from post nasal drainage. No antihistamine was effective. No immunotherapy was effective. The condition lasted 7 years. Upon supplementing her diet with zinc gluconate at 1 mg per pound of body weight, post nasal drainage cleared, her nasal passages returned to normal, and all other symptoms were eliminated. She felt much better and gained weight with an improvement in personal appearance and disposition. She now sleeps in the normal reclining position. Her nasal problem returns if zinc (zinc picolinate) is not supplemented every 12 hours. No adverse reactions occurred.
One adult male subject has 29 years of severe nasal allergy and 15 years of food allergies. Antihistamines were ineffective. Desensitization was attempted 3 times with no permanent improvement. Zinc therapy resulted in immediate reduction in some symptoms. Nasal and food allergies became less pronounced with time. After three months nasal passages were completely normal and food allergies were absent. After three months, challenges with foods that previously produced severe headaches failed to produce any allergic response. Nasal allergy symptoms returned in 18-24 hours without zinc therapy. The individual weighed 160 pounds. Best results occurred with 150 mg zinc in the morning and 150 mg zinc at bed time. See Chandra for toxicity to T-cell system in well subjects, not ill subjects. Chandra found in healthy medical students that double maximum high normal serum levels (300 mmg/DL) 300 mg dietary zinc a day first increased (doubled) T-cell function, but after 30 days, blood serum level gradually rose over the normal upper limit of zinc (150 mmg zinc/dl) and T-cell function fell to 20% of normal. Zinc administration must be controlled and dosage regulated so that serum levels of zinc do not exceed 150 mmg/DL. There is no harm from higher levels if other nutrients (copper, manganese, and iron) are normal or normalized with their concurrent supplementation. In this same case, excessive post nasal drainage with consequent coughing resulted immediately upon exposure to automobile exhaust fumes. Dietary zinc supplementation lessened the frequency and magnitude of the attacks. When 5-20 mg zinc was dissolved in the mouth during these attacks the post nasal drainage ceased within 10 minutes, and did not return for a minimum of 6 hours and then only after re-exposure. Without zinc, the allergic response to automobile fumes was generally continuous. Most sore throats are immediately eliminated with zinc as a throat lozenge (5-20 mg). Other circumstances of allergic reactions were similarly treated with similar responses in many trials. The use of dietary zinc picolinate produced a rapid reduction in nasal allergy symptoms and dilation of nasal passages similar to those found with the use of potent nasal sprays, although the effect became reduced with repeated trials.
Women who have premenstrual cramping, pain and bloating do not have any premenstrual problems at all by taking 30 to 90 mg zinc for a few days prior to the expected problems. In this case, zinc may act as a prostaglandin regulator. Zinc is not an antiprostaglandin but does strongly affect its metabolites.
In many persons, angina pectoris was significantly lessened in frequency and intensity by daily doses of zinc in the 1.5 to 3.0 mg zinc to pounds of body weight range.
One adult male had chronic diarrhea each hour for the previous 21 years. Allergic gastroenteritis due to mast cell degranulation of prostaglandlins within the intestines was believed to be the cause. No other symptoms except occasional depression were present. Zinc supplementation at 1.5 mg zinc/pound of body weight terminated the episodes of diarrhea. After a week of zinc therapy, a severe but temporary depression occurred. This response has been attributed to the displacement of copper by zinc in the brain (Ref. 29, p. 36). Since the depression was temporary, zinc therapy was continued. When zinc therapy was discontinued the diarrhea returned within 3 days.
One male adult had chronic bronchial asthma every evening for 15 years. After 3 days of supplementation with zinc at 1 mg/body pound the asthma did not return. Upon stopping therapy the asthma returned within days.
The same was found for asthma in a 7-year-old girl born of allergic parents. In one instance, when treatment with zinc was terminated in this girl and asthma returned, she was required by her mother to immediately dissolve a 50 mg zinc tablet in her mouth. Asthma symptoms disappeared within minutes and did not return that night. This girl also had frequent bouts with croup. Zinc was found to be an excellent treatment for croup, causing symptoms to disappear within 15 minutes upon dissolving a 50 mg zinc tablet in her mouth. These observations of the effectiveness of zinc in the treatment of croup have been evidenced 5 times with 4 times in the 7-year-old girl and once in a 4-year-old girl. The mother of the 7-year-old girl reported that before zinc was used, croup usually lasted for several days and always required extensive medical treatment. This same child had a life long history of other previously unrecognized zinc deficiency symptoms. As an infant she had constant diaper rash from her waist to her toes that was considered by doctors to be open wounds. She was ill with frequent viral and bacterial infections and was also considered allergic, as well as being subject to asthma and croup. Her weight remained depressed at the 3% line for her age group. Her height remained at the 15-20% line for her age group. She was weak, tired and had circles under her eyes. She was started on 1 mg zinc/pound of body weight and was also taken off of all prescription antihistamines and other drugs. Her health dramatically improved with substantially fewer episodes of previous illnesses and with lessened severity and duration. Allergic symptoms and incidents of asthma and croup occur only when she forgets to take zinc. Incidences of viral and bacterial infections became greatly reduced in frequency and were of a mild nature. Within one year, her weight accelerated to the 30% line, and her height accelerated to the 40% line age adjusted. The child then was considered to have excellent health, was cheerful, strong, alert and no longer had circles under her eyes. Later, the mother reduced the child's zinc intake with a dramatic reduction in weight gain and increases in viral infections including a moderately severe case of roseola.
An 8-month-old male born of allergic parents had already had two major upper respiratory viral infections. Manifestations of atopic allergy were becoming apparent and antihistamines were started with some success. His weight and height were at the 5% and 10% level age adjusted. He had frequent diaper rash. After starting the boy on 10 mg zinc daily, no allergic responses have been since observed and only one minor cold lasting two days occurred over a 24-month period. Episodes of diaper rash became much less frequent and less severe and eventually were eliminated. His weight and height accelerated within one year to the 20% and 35% level age adjusted.
It may be that additional dietary zinc is all that is necessary to break the vicious allergy-upper respiratory, viral infection syndrome so often observed in children born of allergic parents.
These are some examples of the role that zinc has played in the therapy of various types of allergic responses studied. In no case where zinc was used in our experiments was there any other adverse reaction, except when used in conjunction with some antihistamines. Use of zinc with certain antihistamines significantly worsened allergic responses in several cases. Cessation of the use of antihistamines allowed the favorable effect of zinc in these individuals to present itself, with no adverse side effects. In no other case did the continued daily use of zinc either as a dietary supplement or a lozenge fail to reduce or eliminate allergic symptoms. One strange metabolic change not explained was that sleep requirements diminished by 33% in several cases.
A 0.1% zinc (from zinc gluconate) in normal saline spray was found to be effective in tempoarily inhibiting nasal rhinitis.
THE COMMON COLD
Because zinc prevents the release of histamine from mast cells, prevents the replication of rhinoviruses, stimulates effector T-cell lymphocytes in the presence of antigens such as rhinovirus, and further realizing that mast cell degranulation occurs in the inflammation of common colds are suggestive that T-cell lymphocytes and viruses receive zinc in a highly concentrated form from the degranulating mast cells. The zinc is available for transferrin binding; thus resulting in effector T-cell stimulation, lymphoblastic transformation and possibly T-cell interferon release. The zinc released from the mast cell is also directly available to block polypeptide cleavage of viruses.
This concept suggested that zinc supplementation would cause rapid relief from the symptoms of the common cold. Our early tests with zinc and allergies indicated that oral administration of 2 mg zinc/pound of body weight per day would eliminate allergies but not colds.
The first test of slowly dissolving a 50 mg zinc tablet (zinc gluconate) in the mouth as treatment for clinically diagnosed colds in an immunosuppred child suffering from ALL produced very rapid elimination of symptoms (within 2 hours) with no relapse. Such finding resulted from the child's inability and refusal to swallow zinc tablets because her throat was too swollen and irritated to swallow solids.
This phenomena was tested in many other individuals having a common cold in with completely unpredicted results. In forty percent (20) of the 50 early onset cases of the common cold (could have been nasal allergies), all cold symptoms were eliminated within one hour. No return of any symptoms occurred after dissolving a single 50 mg zinc (from zinc gluconate) tablet in the mouth within several hours of the onset of cold symptoms such as nasal drainage. The 2 hour period is significant in that suppressor cells require 2 hours of contact with histamine for suppressor activity to be initiated causing effector cell activity to be suppressed (Ref. 42). Best results occurred when the zinc tablet was chewed and the resulting fluid (very rich in zinc ions) was retained in the mouth to be used as a gargle. It was swallowed after gargling for 20 to 30 minutes. Best results occurred when done within several hours of the onset of the cold. In another forty percent (20) of the cases all cold symptoms were gone upon arising from a night's sleep; 6 lasted 24 hours and 4 lasted 48 hours. In one case of viral pneumonia that had lasted 14 days with substantial loss of body weight, 300 mg of zinc (zinc gluconate) was ingested and repeated several times. All viral pneumonia symptoms were relieved in 12 hours.
In over 50 other cases where zinc gluconate tablets with no other soluble ingredients was dissolved in the mouth at the very first sign of an impending cold, no cold symptoms developed. It would be difficult to verify whether or not a cold would have developed, except for the observed marked reduction in annual colds experienced by the individuals. If treatment with zinc was delayed, so that cold symptoms existed for 24 hours untreated, zinc was not as effective. Most, if not all, of the colds that lasted two days after treatment was started were of this type. The rationale for such rapid recovery was proposed to be the direct anti-viral effect of zinc, stabilization of cell plasma membranes and interferon induction by zinc. Certainly T-cell lymphocyte delayed hypersensitivity was not solely responsible. The best sequence of events hypothesized for these results are as follows:
(1) Mast cell degranulation by virus is terminated by the high level of exogenous extracellular zinc with a subsequent termination of both histamine and mast cell zinc release heparin, bradykinins, and a reduction in nasal drainage, inflammation, swelling and suppressor T-cell potentiation by histamine.
Consequently, viral replication inhibition and interferon induction are seen as the primary methods by which zinc eliminates the common cold in such a short time. Only interferon and viral replication inhibition by zinc are known to have such rapid anti-viral kinetics (Refs. 38,39,49,50).
It is also known that interferon is most effective when given immediately after inoculation with a virus. Zinc is also most effective when given very early in the common cold; as well as in tumors as demonstrated by Worster (Ref. 22, p. 206).
As an additional benefit to rapid recovery from colds, no subsequent bacterial infections occurred. Theoretically, bacterial fighting is diminished with high levels of zinc. However, the time required for a cold to subside with this technique is so short that bacteria apparently do not have the time to multiply significantly prior to a resumption of normal zinc serum levels and normal phagocytotic activity. There were no other after effects or side effects.
The concurrent use of aspirin, cold remedies and alcohol were contraindicated for all individuals due to their adverse effects on CMI and interferon or their potential for enhancing allergic responses when using zinc (Ref. 4, p. 71). Aspirin also lowers body temperature (which is an important host defense mechanism). It has been demonstrated that patients using aspirin with viral respiratory infections shed virus longer than controls, suggesting that the infection may be made more severe when aspirin is used.
ACUTE LYMPHOCYTIC LEUKEMIA
For one and one-half years prior to the development of ALL, the 3-year-old female had among other symptoms recurrent and severe allergies and upper respiratory viral infections averaging 3 to 4 attacks per month. Since initiation of chemotherapy with zinc, no allergic reactions occur and only 7 very minor upper respiratory viral infections have occurred lasting less than 2 days each over a two-year period. The use of the zinc gluconate lozenges resulted in very rapid elimination of all cold symptoms. It was uncertain as to the actual role of zinc in the diminution of the earlier allergic and viral immunity problems, since predisone could have eliminated the allergic response.
Tests were needed in other subjects with ALL to ascertain if zinc could produce the potentiated immune response thought to have occurred in the 3-year-old girl. A thirteen-year-old male with ALL for 15 months was identified and was interested in the experiment. This boy had missed 90%-95% of his school since diagnosis of ALL due to severe and recurrent upper respiratory infections. Upon use of zinc therapy at 1 mg/pound of body weight, no school was subsequently missed in the following semester and the incidence of upper respiratory distress became greatly diminished. A significant increase in neutrophil count (ANC) was also observed to accompany the use of supplemental zinc in this case, although the Polish experience did not demonstrate an increase in ANC. No increase in lymphocyte count was noted. These observations were replicated anecdotally in 12 children from 1985 to 1996.
These anecdotal observations if verifiable in double blind clinical studies have immense practical application in both minor upper respiratory infections and major viral illnesses in children with ALL, and perhaps other malignant disorders as well. For instance a strong CMI is necessary for inactivation of varicella-zoster virus and survival of this disease in children with ALL (Ref. 40). It now becomes apparent that calamine lotion, a zinc preparation, has more than an itch relief function in chicken pox.
After two years of treatment for ALL using protocol 161 regimen 2 (with zinc) the young subject of this review developed a titer of 1,024 to chicken pox virus and demonstrated adequate CMI response to chicken pox in vitro after inoculation to chicken pox with the Japanese vaccine. Normally, chicken pox titer does not go above 100 in ALL.
This child's zinc serum level was measured frequently during the preceding years and was found to be in the 130-140 mcg/dl range. Zinc administration was by oral supplementation at the rate of 1-2 mg/pound/day. All other vitamins (except folic acid), minerals and trace minerals were given daily in adult therapeutic dosages. It is not known if the other nutrients interacted with zinc to improve the response to therapy beyond preventing chemotherapy-induced deficiencies.
During the 3 years of maintenance therapy, a continuous M-1 remission (in her case 0.2 to 1.5 percent bone marrow blasts) was maintained. Treatment was ended at the end of the third year. The child's health remained excellent, and she was not subject to incidence of infection in excess of the normal population. Her blood count returned to normal within 3 months post ALL treatment cessation.
She went to kindergarten and stayed up with her classmates in all areas. She excelled in physical sports and could swim over one mile with her "wingies" when she was 4 years old She remained on the 50 percentile line for height and weight and showed no trace of her ordeal in any manner.
1987 update - same as third grade update.
IX. CLINICAL TRIALS -- COMMON COLD
Due to the anecdotal observations cited above showing efficacy of zinc gluconate 23 mg zinc lozenges in treating the common cold, clinical trials were initiated.
As of December 8, 1981, 107 persons had been successfully treated in Phase I of randomized, double-blind clinical experiments conducted by Dr. William W. Halcomb, D.O. of Austin, Texas. All persons are examined by Dr. Halcomb and only those with symptoms of viral upper respiratory infection are admitted to the study.
Phase I incorporated only the use of throat-lozenges (tablet) containing 23 mg zinc (from zinc gluconate) or the placebo according to the Treatment Instructions in Appendix II (essentially 23 mg zinc as throat lozenge each 2 hours).
Preliminary results from the first 107 subjects indicate that the zinc treated group endured cold symptoms for a significantly shorter period than controls (P < .0001, 1 tail T test). The zinc treated group endured cold symptoms for an average of 2 days while the control group averaged in excess of 7 days. Twenty-five percent of the zinc treated group had no cold symptoms after one day of treatment, whereas none of the control group were free of symptoms in the same period of time. Over 50% of the control group had symptoms in excess of 7 days while only 10% of the zinc treated group had symptoms in excess of 7 days. As much as 50% of the symptoms of the zinc treated group are absent at the end of the first twenty-four hours. No unexpected side effects occurred and no complaints more significant than objection to taste resulting in nausea and vomiting have yet been observed
Phase II included a more pleasant tasting zinc compound (37 mg zinc from insoluble and non ionizable zinc orotate) a stronger initial treatment and an 0.1% zinc (from zinc gluconate) normal saline nasal spray. Because zinc orotate is both non soluble in water and therefore non ionizable there were null results. The zinc gluconate nasal spray acted as a decongestant having an effect for only 15 to 30 minutes.
Before the content of this review was visualized, this writer had only one research goal in mind. That goal was to determine if there was any singular nutrient that could be associated with the leukemic process. It did not take long to find pieces of the zinc-leukemia puzzle scattered throughout the literature. However, what was difficult was to understand what the pieces meant and where they fit into the leukemia puzzle.
What is leukemia and what is zinc's role in leukemia? It is this writer's belief that understanding zinc is of paramount importance to understanding leukemia. Furthermore, it is hypothesized that the etiology of leukemia is coupled to zinc metabolism and perhaps to the current treatment of viral infections using immunosuppressants such as aspirin.
Assume that acute lymphocytic (lymphoblastic) leukemia is caused by an RNA-tumor virus that is subject to control by zinc as indicated by Phillips, Korant and Eby. (See AIDS Discussion in Handbook, for Curing the Common Cold too.) Further, assume that the method used by this virus for host immunosuppression is one of zinc depletion by the virus mimicking the ability of bacteria to cause LEM to be excreted from Leukocytes to signal the liver to withdraw zinc from the serum. At this point in time, EP is also released and a fever results. Assume that aspirin is administered over a prolonged time in order to combat this fever, then further immunosuppression occurs. As zinc serum levels fall, steroid levels rise, thymic function falls, growth is arrested, immunosuppression increases, allergic reactions occur, frequent upper respiratory infections and other infections occur, taste and appetite become impaired, lethargy and depression occur, diarrhea and finally offensive body odor (caused by improper protein synthesis resulting in an accumulation of asparagine) occurs. At some point the immune system loses control, the process becomes irreversible and frank leukemia ensues. Even many of the routinely observed symptoms of leukemia can be postulated to be caused by zinc depletion as well as by the proliferation of blasts:
1. Anemia: By depletion of red cells of iron transferrin (since zinc is necessary for transferrin synthesis) resulting in failure of carbonic anhydrase and hemolysis,
Upon administration of chemotherapy, leukemic cells are killed, the impact of LEM in depleting bioavailable zinc is reduced and a balance is achieved in which leukemic cells are controlled. If sufficient zinc and other nutrients necessary for protein synthesis are administered along with the chemotherapy, immunostimulation by several methods occurs resulting in a strengthened CMI response, normalized growth occurs, minimized asparagine synthesis, and an anti RNA-tumor virus effect occurs. Although normal T-cells are zinc dependent, leukemic cells are not dependent of zinc for their replication. Hopefully the remainder of the leukemic cells are thus eliminated.
In clinical practice a clear correlation appears between the return of bioavailable zinc serum levels to normal and the prospects for survival. However, no modern leukemia therapy (with the exception of the Polish trials) uses zinc. The Polish trials used zinc in small doses. Even at those low doses, CMI was stimulated.
Aspirin is completely contraindicated in the leukemia recovery process, thus suggesting that its influence in blood function is enough to tip the balance from life to death for the victim. Steroids and other chemotherapy agents are also immunosuppressive. Zinc may offset the immunosuppressive function of steroids without increasing the lymphocyte count.
In our own pre clinical trial experiments to ascertain if zinc could increase resistance to viruses, astoundingly rapid recoveries from the common cold were regularly noted. This effect was probably not singularly due to an activated T-cell system but due to a direct anti-viral property of zinc. Even so, zinc can be used to completely eliminate a variety of viruses possibly including RNA tumor viruses if suitable techniques for its use can be developed. These very early experiments were simple demonstrations that indicated that all that has ever been needed to rapidly and completely cure many common colds and other viral infections was to raise the level of zinc to levels that, although harmless to the cells and strengthened cell plasma membranes, was highly inhibitory to viruses, due to several mechanisms. Only zinc has the quadruple capacity for the safe control of viruses, cell mediated immunity stimulation, antiprostaglandin activity, and strong antihistaminic action and cell plasma membrane stabilization. It is probable that no pharmaceutical preparation will ever approach zinc in its efficacy, low cost, safety, availability and gentleness in rapid virus control. It will, if its use is not purposefully suppressed, become the greatest anti-viral agent ever used or ever developed.
In summary, zinc needs much more attention in the study of leukemia, and virus management as well as in the correction of mast cell irregularities. Zinc does meet the original objective of this writer. Zinc can, in this writer's opinion, influence the incidence of leukemia and the outcome of leukemia and should be tested (1.5 mg zinc per pound body weight) in double blind clinical studies as an adjunct to standard treatment compared to standard treatment without added dietary zinc. It is therefore suggested that there is substantial need for controlled clinical studies of:
This is the original experimental protocol used for the published 1984 clinical trial of 23 mg zinc (from zinc gluconate).
These instructions have been developed over a three year period. They are believed to be the best way to insure a rapid recovery from the common cold.
AT THE OFFICE VISIT:
At the office visit with the physician, the patient was given a bottle of medication to use to treat the common cold. The patient, whether adult, youth, or child, is to ALLOW THE TABLET TO SLOWLY DISSOLVE 2 TABLETS IN THE MOUTH. The patient is to slowly allow the first tablet and then the second one to dissolve in the mouth. The object of this treatment is to directly absorb the medicine through the mucosal membranes of the mouth and throat.
HOME FOLLOW-UP TREATMENT:
ALLOW TABLETS TO SLOWLY DISSOLVE IN THE MOUTH. The treatment may be slightly varied to meet personal requirements. However, do not exceed the maximum daily dosages. It is advantageous to take the medication during the night time sleep period. However, it is not advisable to interrupt sleep more than once a night solely to receive treatment. Treat as follows:
Allow 1 tablet to slowly dissolve in the mouth every 2 hours. The dosage for day 1 is 10 tablets.
The dosage for days 2 - 7 is 9 tablets each day.
IMPROVING THE RESULTS: In order to insure the best results and not to interfere with the effectiveness of the medication:
1. Rudolph, Abraham M., Editor. PEDIATRICS, 16th Edition (New York: Appleton-Century-Crofts), 1977.
2. Barrett, J.T. TEXTBOOK OF IMMUNOLOGY (St. Louis: The C.V. Mosby Company, 1978), p. 320.
3. Risby, T.H., Prasad, A.S., et al. "Ultratrace Metal Analysis Biological Sciences and Environment," ADVANCES IN CHEMISTRY SERIES NO. 172 (Washington, D.C.: American Chemical Society, 1979).
4. Poustovoi, I., et al. "Immunodeficiency, Report of a WHO Scientific Group," TECHNICAL REPORT SERIES 630, World Health Organization, Geneva, Switzerland, 1978.
5. Reinherz, E.L., et al. "Regulation of the Immune Response--Inducer and Suppressor T-lymphocyte Subsets in Human Beings," THE NEW ENGLAND JOURNAL OF MEDICINE, Vol. 303, No. 7, pp. 370-373, August 1980.
6. Prasad, A.S., et al. TRACE ELEMENTS IN HUMAN HEALTH AND DISEASE, VOLUME I (New York: Academic Press, 1976).
7. Golden, M. et al. "Effect of Zinc on Thymus of Recently Malnourished Children," THE LANCET pp. 1057-1059, November 1977.
8. Chandra, R.K. "Nutritional Deficiency and Susceptibility to Infection," BULLETIN OF THE WORLD HEALTH ORGANIZATION, Volume 57 (2), pp. 167-177, 1979.
9. Hart, David A. "Augmentation of Zinc Ion Stimulation of Lymphoid Cells by Calcium and Lithium," EXPERIMENTAL CELL RESEARCH, Volume 121, pp. 419-426, 1979.
10. Manzella, J.P., and Roberts, N.J. "Human Macrophage and Lymphocyte Response to Mitogen Stimulation after Exposure to Influenza Virus, Ascorbic Acid, and Hyperthermia," THE JOURNAL OF IMMUNOLOGY, Vol. 123, No. 5, pp. 1940-1944, Nov. 1979.
11. Krieger, I. and Evans, G.W. "Acrodermatitis Enteropathica Without Hypozincemia," JOURNAL OF PEDIATRICS, Vol. 96, No. 1, Pp. 32-35, January 1980.
12. Oleske, J.M., et al. "Zinc Therapy of Depressed Cellular Immunity in Acrodermatitis Enteropathica," AMERICAN JOURNAL OF DISEASES OF CHILDREN, Vol. 133, pp. 915-918, September 1979.
13. Bj÷rksten, B., et al. "Zinc and Immune Function in Down's Syndrome," ACTA PAEDIATRICA SCANDINAVICA, Vol. 69, No. 2, pp. 183-187, March 1980.
14. Pekarek, R.S., et al. "Abnormal Cellular Immune Responses During Acquired Zinc Deficiency," AMERICAN JOURNAL OF CLINICAL NUTRITION, Vol. 32, pp. 1466-1471, 1979.
15. Shaw, J.C.L. "Trace Elements in Fetus and Young Infant," AMERICAN JOURNAL OF DISEASES OF CHILDREN, Vol. 133, pp. 1260-1268, December 1979.
16. Chandra, R.K. "Single Nutrient Deficiency and Cell Mediated Immune Responses I. Zinc," THE AMERICAN JOURNAL OF CLINICAL NUTRITION, Vol. 33, No. 4, pp. 736-738, April 1980.
17. Phillips, Jerry L., et al. "Zinc Transferrin, Enhancement of Nucleic Acid Synthesis in Phytohemagglutin-Stimulated Human Lymphocytes," CELLULAR IMMUNOLOGY, Vol. 10, pp. 31-37, 1974.
18. Berendt, M.J., et al. "T-Cell Mediated Suppression of Anti-Tumor Immunity," THE JOURNAL OF EXPERIMENTAL MEDICINE, Vol. 151, No. 1, pp. 69-80, January 1980.
19. Gleicher, N. et al. "Leukocyte Migration Enhancement as an Indicator of Immunologic Enhancement," AMERICAN JOURNAL OF OBSTETRICS AND GYNECOLOGY, Vol. 136, No. 1, pp. 1-10 and 126-131, Jan. 1, 1980.
20. Abramson, H.N., et al. "Therapeutic Uses of Oral Zinc," U.S. PHARMACIST, pp. 61-66, April 1979.
21. Suzuki, K. and Tomasi, T.B. "Immune Responses during Pregnancy," JOURNAL OF EXPERIMENTAL MEDICINE, Vol. 150, No. 4, pp. 898-908, 1979.
22. Nriagu, J.O., Phillips, Jerry L., and Kindred, Mary K. ZINC IN THE ENVIRONMENT, PART II: HEALTH EFFECTS (John Wiley & Sons, Inc., 1980), pp. 199-213.
23. Private correspondence with David A. Hart, Dept. of Microbiology, University of Texas Health Science Center at Dallas, and Samuel T. Baron, University of Texas School of Medicine at Galveston.
24. Lyman, Gary H., et al. "The Use of Lithium Carbonate to Reduce Infection and Leukopenia during Systemic chemotherapy," THE NEW ENGLAND JOURNAL OF MEDICINE, Vol. 302, No. 5, pp. 257-260, Jan. 1980.
25. Prasad, A.S. "Nutritional Deficiencies in Man: Zinc." CRC HANDBOOK SERIES IN NUTRITION AND FOOD, Section E, Vol. III, pp. 261-269, 1978.
26. Krause, M.V., and Mahan, L.K. FOOD, NUTRITION AND DIET THERAPY, SIXTH EDITION (Philadelphia: W.B. Saunders Co., 1979).
27. Garretts, M., et al. "Acrodermatitis Enterophathica Without Hypozincemia," JOURNAL OF PEDIATRICS, Vol. 91, No. 3, pp. 492-494, September 1977.
28. Buisseret, Paul. "Drug Treatment of Allergic Gastroenteritis," THE AMERICAN JOURNAL OF CLINICAL NUTRITION, Vol. 33, pp. 865-871, April 1980.
29. Pfeiffer, C. ZINC AND OTHER MICRO-NUTRIENTS (New Canaan, Connecticut: Keats Publishing, Inc. 1978).
30. Cutler, E.O., et al. Correspondence, THE NEW ENGLAND JOURNAL OF MEDICINE, Vol. 297, No. 3, pp. 168-169, July 21, 1977.
31. Private correspondence with Jerry Phillips, Division of Life Sciences and Allied Health, University of Texas at San Antonio.
32. Belanger, L.F. "The Influence of Zinc-Deprivation on the Mast Cell Population of the Bone Marrow and Other Tissues," JOURNAL OF NUTRITION, Vol. 108, pp. 1315-1321, 1978.
33. Prasad, K.N., et al. "Sodium Ascorbate Potentiates the Growth Inhibitory Effect of Certain Agents on Neuroblastoma Cells in Culture," PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES, U.S.A. Vol. l76, No. 2, pp. 829-832, February 1979.
34. Elspar Technical Description, Merck & Co., 1977.
35. Fang, M.M., et al. "Effects of Zinc Deficiency on Dental Caries in the Rat," THE JOURNAL OF NUTRITION, Vol. 110, pp. 1032-1036, 1980.
36. Boyle, M.D.P., et al. "Studies on the Terminal Stages of Immune Hemolysis IV. Effect of Metal Salts," THE JOURNAL OF IMMUNOLOGY, Vol. 122, No. 4, pp. 1209-1213, April 1979.
37. Duchateau, J., et al. "Influence of Oral Zinc Supplementation on the Lymphocyte Response to Mitogens of Normal Subjects," AMERICAN JOURNAL OF CLINICAL NUTRITION, Vol. 34, No. 1, pp. 88-93, January 1981.
38. Dianzani, F., et al. "Kinetics of the Rapid Action of Interferon," PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE, Vol. 152, pp. 593-597, 1976.
39. Harmon, M.W. "Effect of Human Nasal Secretions on the Antiviral Activity of Human Fibroblast and Leukocyte Interferon," PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE, Vol. 152, pp. 598-602, 1976.
40. Gershon, A.A., et al. "Cell Mediated Immunity to Varicella-Zoster Virus Measured by Virus Inactivation: Mechanism and Blocking of the Reaction by Specific Antibody," INFECTION AND IMMUNITY, Vol. 25, No. 1, pp. 164-174, July 1979.
41. Miller, R.C., et al. "Oncogenic Transformation of Mammalian Cells in Vitro with Split Doses of X-Rays," PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES, USA, Vol. 76, No. 11, pp. 5755-5758, November, 1979.
42. Rocklin, Ross E., et al. "Histamine Activates Suppressor Cells in Vitro Using a Coculture Technique," JOURNAL OF CLINICAL IMMUNOLOGY, Vol. I, No. I, pp. 73-79, 1981.
43. INTERFERON I (New York, Academic Press, 1979).
44. Brohult, A. "B-Globulin Concentration and Treatment of Infantile Leukemia" from the Pediatric Clinic, Kronprinsessan Louisas Barnsjukhus, Stockholm, Sweden, July 1953.
45. Czyzewska, M.W., et al. "Immunostimulatory Effect of Zinc in Patients with Acute Lymphoblastic Leukemia," FOLIA HAEMATOL, LEIPZIG, Vol. 105 (6), pp. 727-732, 1978.
46. Good, Robert A. "Nutrition and Immunity," JOURNAL OF CLINICAL IMMUNOLOGY, Vol. 1, No. 1, pp. 3-11, 1981.
47. Bogomolova, G.G. And Karlinskii, V.M. "Indices of Zinc Metabolism in Leukemias," VRACH DELO, Vol. 12, pp. 57-61, 1977.
48. Milman, H.A., Ward, J.M., and Cooney, D.A. "Inhibition of L-Asparagine Synthetase by Mineral Cations," TOXICOLOGY AND APPLIED PHARMACOLOGY, Vol. 50, No. 3, pp. 573-580, 1979.
49. Korant, Bruce D., et al. "Zinc Ions Inhibit Replication of Rhinoviruses," NATURE, Vol. 248, No. 5449, pp. 588-590, April 12, 1974.
50. Korant, Bruce D. and Butterworth, Byron. "Inhibition of Rhinovirus Protein Cleavage: Interaction of Zinc with Capsid Polypeptides," JOURNAL OF VIROLOGY, Vol. 18, No. 1, pp. 298-306, April 1976.
51. Perez-Bercoff, R., Editor. THE MOLECULAR BIOLOGY OF PICORNAVIRUSES (Plenum Publishing Corporation), 1979.
52. Butterworth, Byron E. and Korant, Bruce D. "Characterization of the Large Picornaviral Polypeptides Produced in the Presence of Zinc Ion," JOURNAL OF VIROLOGY, Vol. 14, No. 2, pp. 282-291, April 4, 1974.
53. Shlomai, Joseph, et al. "Effect of Zinc Ions on the Synthesis of Herpes Simplex Virus DNA in Infected BSC-1 Cells," VIROLOGY, Vol. 66, pp. 330-335, 1975.
54. Gordon, Yitzhak J., et al. "Irreversible Inhibition of Herpes Simplex Virus Replication in BSC-1 Cells by Zinc Ions," ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, Vol. 8, No. 3, pp. 377-380, 1975.
55. Gupta, Phalguni and Rapp, Fred. "Effects of Zinc Ions on Synthesis of Herpes Simplex Virus Type 2-Induced Polypeptides," PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE, Vol. 152, pp. 455-458, 1978.
56. Fridlender, Bertold, et al. "Selective Inhibition of Herpes Simplex Virus Type 1 DNA polymerase by Zinc Ions," VIROLOGY, Vol. 84, pp. 551-554, 1978.
57. Polatnick, Jerome, et al. "Effect of Zinc and Other Chemical Agents on Foot-and-Mouth Disease Virus Replication," ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, Vol. 13, No. 5, pp. 731-734, May 1978.
58. Katz, Ehud, et al. "Inhibition of Vaccina Virus Maturation by Zinc Chloride," ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, Vol. 19, No. 2, pp. 213-217, Feb. 1981.
59. Wahba, A. "Topical Application of Zinc-Solutions: A New Treatment for Herpes Simplex Infections of the Skin," ACTA DERMATOLOGY VENEREOL (STOCKHOLM), Vol. 60, No. 2, pp. 175-177, 1980.
60. Fahim, M.S., et al. "Treatment of Genital Herpes Simplex in Male Patients," ARCH ANDROL, Vol. 4, No. 1, pp. 79-85, Feb. 1980.
61. Fahim, M.S., et al. "New Treatment for Herpes Simplex Virus Type 2 with Ultrasound and Zinc, Urea and Tannic Acid Ointment Part 1 Male, and Part 2 Female," JOURNAL OF MEDICINE, Vol. 9, No. 3, pp. 245-264, 1978 and Vol. 11, No. 2 and 3, pp. 143-167, 1980.
62. Lasson, U. et al. "Zinc Deficiency Syndrome in Children Treated for Leukemia," DTSCH MED. WOCHENSCHR. Vol. 104, No. 36, pp. 1283, 1979.
63. Vallee, B.L. "Zinc Biochemistry in normal and neoplastic growth," EXPERIMENTIA, Vol. 33, No. 5, pp. 600-601, 1977.
64. Auld, D.S. et al. "Reverse Transcriptase from Avian Myeloblastosis Virus: A Zinc Metalloenzyme," BIOCHEMICAL, BIOPHYSICAL RESEARCH COMMUNICATION, Vol. 57, No. 4, pp. 967-972, 1974.
65. Auld, D.S., et al. "RNA-Dependent DNA Polymerase (Reverse Transcriptase) from Avian Myeloblastosis Virus: A Zinc Metalloenzyme," PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES, USA, Vol. 71, No. 5, pp. 2091-2095, 1974.
66. Dreizen, S. "Nutrition and the Immune Response--A Review," INTERNATIONAL JOURNAL OF VITAMIN AND NUTRITIONAL RESEARCH, Vol. 49, No. 2, pp. 220-228, 1979.
67. Bendtzen, K. "Differential Role of Zn+2 in Antigen and Mitogen Induced Lymphokine Production," SCANDINAVIAN JOURNAL OF IMMUNOLOGY, Vol. 12 (6), pp. 489-492, 1980.
68. Duchateau, J. et al. "Beneficial Effect of Oral Zinc Supplementation on the Immune Response of Old People," THE AMERICAN JOURNAL OF MEDICINE, Vol. 70, pp. 1001-1004, May 1981.
69. Chan, H., et al. "Lithium Therapy of Children with Chronic Neutropenia," THE AMERICAN JOURNAL OF MEDICINE, Vol. 70, pp. 1073-1077, May 1981.
70. Chandra, R.K. "Immune Response in Over-Nutrition," CANCER RESEARCH, Vol. 41, Part 2 (9), pp. 3795-3796, September 1981.
71. Marone, G., et al. "Inhibition of Histamine-Release from Human Basophils by Zinc-Chloride," FEDERATION PROCEEDINGS, Vol. 37, No. 3, p. 590, 1978.
72. Horrobin, D.F. "The Reversibility of Cancer: The Relevance of Cyclic AMP, Calcium, Essential Fatty Acids and Prostaglandin El," MEDICAL HYPOTHESES, Vol. l6, pp. 469-486, 1980.
73. Das, U.N. "Cell Membrane Fluidity and Prostaglandins," MEDICAL HYPOTHESES, Vol. l7, pp. 549-553, 19481.
74. Marone, et al. "Modulation of basophil histamine release by zinc," JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY, 1979, 65:171.
75. Bor, N.M. "Zinc and copper deficiency in patients with allergic diseases and treatment with zinc sulfate -- preliminary report." NEW ISTANBUL CONTRIBUTION TO CLINICAL SCIENCE, 1980, 13:58-59.
76. Epstein, J. "SV40 - transformed human cells fail to grow in zinc concentrations which permit normal human fibroblast proliferation.," JOURNAL OF CELLULAR PHYSIOLOGY, 1982, 110;17-22.
77. Harrell, R.F., Capp, R.H., Davis, D.R., Peerless, J., and Ravitz, L.R. "Can nutritional supplementation help mentally retarded children? An exploratory study," PROC NATL ACAD SCI USA, Vol. l78, No. 1, pp. 574-578, Jan. 1981.
78. Tiber, A.M., and Mukherjee, M.D. "Clinical Manifestations of Zinc Deficiency," AMERICAN FAMILY PHYSICIAN, Vol. 26, No. 2, pp. 167-172.
79. Stout, M.G. and Rawson, R.W. "Minerals, Trace Elements, and Cancer," NUTRITION AND CANCER: ETIOLOGY AND TREATMENT. Ed. G.R. Newell and N.M. Ellison. Raven Press, New York, 1981, pp. 243-271.
80. Morser, J. and Colman, A. "Post-translational Events in the Production of Human Lymphoblastoid Interferon," J. GEN VIROL (1980), Vol. 51, 117-124.
81. Vogt, V.M., Eisenman, R. and Diggelmann, H. "Generation of avian myeloblastosis virus structural proteins by proteolytic cleavage of a precursor polypeptide," J. MOL BIOL, 1975, 96:471-93.