The Nutritional Relationships of Zinc David L. Watts, D.C., Ph.D., F.A.C.E.P.i Zinc was discovered to be essential for the also indicate tissue redistribution.12 The normal growth of living organisms in 1869. The range of zinc in the hair has been reported suspicion that zinc deficiency occurs in man is between 15 and 22 milligrams percent,4 the ideal relatively recent. In 1963, studies reported by being 20 milligrams Prasad and co-workers on Iranian men suffering percent. from dwarfism and hypogonadism found that nutritional zinc deficiency was a causative factor Manifestations of Zinc Deficiency Absolute or in these disorders.1 2 3 Since that time zinc has Relative gained a greater recognition for its role in human Manifestations of zinc deficiency will vary health and has stimulated extensive research. It is from one individual to another. This is true of now known that zinc is essential to over 100 almost any nutrient, and can be explained by enzymes in the body. Perhaps one of the most recognizing that two types of a deficiency state important discoveries is zinc's involvement in the can occur, either a relative deficiency, or synthesis of RNA. absolute deficiency. An absolute deficiency develops as a result of inhibited absorption Distribution accompanied by a concurrent increase in zinc The highest concentration of zinc is found in excretion or utilization. TMA patterns usually the choroid of the eye and optic nerve, followed reveal a low tissue zinc (less than 12 mg.%). An by the prostate, bone, liver and kidneys, muscles absolute deficiency of zinc can be contributed to (zinc content varies with colour and function of by hypoadrenocorticism, hyperthyroidism and muscles), heart, spleen, testes, brain, and other endocrine factors. adrenals. The skin also has a high concentration A relative deficiency develops as a result of of zinc and can often be a sensitive indicator of zinc loss from tissue storage (compart-mental zinc status. A zinc deficiency can adversely affect displacement), without an increase in excretion. any of these organs. A relative deficiency is seen on TMA results where the zinc level is within the normal range Zinc Evaluation Through Tissue Mineral but relatively low when compared to an Analysis (TMA) of Human Hair antagonistic mineral such as copper, or Hair TMA testing can be a good method of cadmium (low Zn/Cu, low Zn/Cd). A relative assessing zinc status and requirements in deficiency state can be contributed to by adrenal individuals. Even though tissue mineral levels in insufficiency, hypothyroid, and hair are not sensitive to acute zinc depletion, hyperparathyroidism. As an example, studies which is rare, it is considered one of the best performed on a group of pregnant women methods for determining long-term nutritional compared to a control group revealed that 5 6 7 zinc status. Since zinc is an intracellular urinary zinc excretion was not significantly element, it is agreed by most authorities that different from nonpregnant controls except plasma, serum, and erythrocyte levels are not during certain months. Trace element analysis of 8 9 10 11 sensitive indicators of zinc status. As with the hair on both groups revealed a gradual most trace elements, the blood levels are increase in tissue zinc levels in the test group maintained at the expense of tissue and are toward the end of the pregnancy.18 It is well therefore, the last to reflect a chronic mineral known that copper levels rise during pregnancy deficiency. A low level of zinc found in the as well as during oral contraceptive and estrogen serum or plasma may indicate a deficiency, but it therapy.19 This is usually reflected on TMA may studies21 and would apparently indicate that copper causes a relative deficiency rather than 1. P.O. Box 5822, Savannah, Georgia 31414. absolute deficiency of zinc. This 63 Journal of Orthomolecular Medicine Vol. 3, No. 2, 1988 may be explained by the metabolic effects of copper relationship. Apparently a relative zinc copper. First, copper is considered an anabolic deficiency produces abnormal taste and smell mineral, therefore, it may increase the metabolic particularly to protein. This phenomena is not requirements for zinc which is also required for often seen in absolute deficiency states. In fact, anabolic processes. Secondly, an increase in individuals with an absolute deficiency of zinc parathyroid activity is known to increase zinc have a greater desire for protein. This could be retention,21 and suppress thyroid and adrenal explained by the difference in the hydrochloric activity22 which would contribute to a decrease in acid status of these individuals. zinc excretion. Both the parathyroid and thyroid glands are affected by copper. Any of these Viruses conditions would produce a relative deficiency of Zinc has an antiviral effect, particularly on zinc by producing compartmental displacement. many forms of rhinoviruses. In vitro it has been Even though the TMA zinc level may be normal, found to affect poliovirus in high the low zinc to copper ratio (less than 8 to 1), concentrations. The antiviral effects of zinc would indicate an increased requirement for zinc. have been found to be even more effective when given in conjunction with vitamin A, and Conditions Associated with Zinc Deficiency magnesium. Zinc deficiency is associated with a One of the most serious manifestations of zinc decrease in immune response and increased deficiency is seen in acrodermatitis enteropathica, susceptibility to viral infections. a genetic disorder that occurs in children.24 Serum and hair zinc levels are both found low in Zinc Deficiency and Visual Disturbances children with this condition and who respond Relative deficiencies of zinc can cause visual well to zinc supplementation. This condition is changes known as dyschromatopsia, a associated with an absolute zinc deficiency. disturbance of the red/green color axis23 Zinc deficiency has been found in patients with characterized by an inability to distinguish lupus erythematosus, scleroderma, psoriasis, skin easily between certain shades of greens and blemishes and rashes, and slow wound healing. blues. Dyschromatopsia is commonly seen in individuals with low tissue zinc to copper ratios. Sickle Cell Anemia Zinc deficiency is seen in people suffering from sickle cell anemia.27 It has been found that Striae (Stretch Marks) in sickle cell disease excessive calcium The integrity of the skin depends upon accumulates within the red blood cells con- adequate levels of zinc due to its involvement in tributing to their deformity. Zinc has proven protein synthesis and collagen production. beneficial due to its effect of decreasing calcium Striae, commonly known as stretch marks, has infiltration into the erythrocytes. been found to be associated with zinc deficiency. Striae occur due to a breaking of Diabetes skin collagen tissue resulting in scar formation. Zinc is also known to be required for insulin This often develops during pregnancy, weight 25 storage. Zinc depletion has been found to occur in gain (seen in body builders), and obesity. some forms of diabetes, most notably juvenile Mechanical strain on the skin can produce type. Individuals with adult onset diabetes also stretch marks and may be seen around the show a need for zinc which is due to increased breasts of zinc deficient women. Clinically, requirements as a result of increased anabolic striae can indicate a relative or absolute demands. deficiency of zinc by its colour. A relative zinc deficiency is associated with white, or silver Anorexia Nervosa striae. Red to purple striae are seen in Taste disorders and a loss of smell is common individuals with an absolute zinc deficiency with zinc deficiency.28 Individuals suffering from status, and is commonly associated with anorexia nervosa have been found to have hyperadrenocorticism,26 or prolonged relative zinc deficiencies with a very low zinc to corticosteroid therapy. 64 The Nutritional Relationships of Zinc Fingernail White Spots inflamma-tories such as corticosteroids and Pfeiffer described white spots that appear in diuretics such as thiazides are commonly used the fingernails as being due to a zinc deficiency.29 medications that can also adversely affect zinc TMA research indicates that these are more likely status. Alcohol is known to produce a diuresis of to be copper toxic spots rather than zinc deficient zinc and increase iron absorption or retention. spots. They are more commonly seen in Diets high in phytates also decrease zinc individuals with relative zinc deficiency states absorption. rather than in those with an absolute deficiency. Minerals Antagonistic to Zinc White spots in the nails are frequently seen in There are many nutritional factors that can individuals with TMA zinc levels within the affect zinc requirements either favourably or normal range, but relatively low in relation to unfavourably. These include both vitamins and copper. White spots are not often seen in minerals. Figure 1 indicates the minerals that are individuals with tissue zinc levels as low as fifty antagonistic to zinc.13 14 15 16 17 Excessive intake percent of normal. or tissue accumulation of any one or The following is a list of conditions observed combination of these trace elements can through TMA studies over the past several years contribute to zinc deficiency by exerting either that have been associated with zinc deficiency. an absorptive or metabolic antagonistic effect. They are categorized according to either a relative Excessive accumulation or toxicity of most of (R), or absolute (A) zinc deficiency. the antagonistic elements shown in Figure 1 can Pregnancy (R), Premenstrual Syndrome be treated with zinc therapy, especially the (R), Autism(R), A.I.D.S. (R), Candida heavy toxic metals such as lead (Pb), Cadmium (R), Eclampsia (R), Anorexia Nervosa (Cd), and Mercury (Hg). (R), Post Partum Depression (R), It should also be noted that excessive intake Schizophrenia (R), Viruses (R), Fungus of zinc over prolonged periods can produce a (R), Depression (R), Manic Depression deficiency of chromium (Cr), copper (Cu), (A), Arthritis Rh.