Low dietary zinc alters indices of copper function and status in postmenopausal women

OBJECTIVES: To better define the relationship between dietary zinc and copper for humans so that sound recommendations for intakes of these elements can be made. METHODS: A study was conducted to ascertain the effect of moderately excessive and deficient intakes of zinc on copper metabolism and use in humans fed low and luxuriant amounts of copper. Twenty-one postmenopausal women housed in a metabolic unit completed the study as designed. After a 10-d equilibration period in which they were fed a diet providing 31.5 micromol (2 mg) Cu and 91.8 micromol (9 mg) Zn/8.4 MJ (2000 kcal), the women were divided into two groups. One group was fed a diet containing 15.7 micromol (1 mg) Cu/8.4 MJ (2000 kcal), and the other group was fed a diet containing 47.2 micromol (3 mg) Cu/8.4 MJ (2000 kcal). After equilibration, both groups were fed the basal diet providing 45.9 micromol (3 mg) Zn/8.4 MJ (2000 kcal) for 90 d; this was followed by another 10-d equilibration period before dietary zinc was increased to 811 micromol (53 mg)/8.4 MJ (2000 kcal) for 90 d. RESULTS: The women were in positive copper balance only when the diet provided 47.2 micromol (3 mg) Cu and 811 micromol (53 mg) Zn/d. Immunoreactive ceruloplasmin concentrations and platelet cytochrome-c oxidase activity on a platelet number basis were significantly lower and the ratio between enzymatic and immunoreactive ceruloplasmin was significantly higher during low dietary than during high dietary zinc intake. Serum cholesterol was higher in subjects fed 15.7 micromol (1 mg) Cu/d than in those fed 47.2 micromol (3 mg) Cu/d. Total and low-density lipoprotein cholesterol concentrations decreased with zinc supplementation. Whole-blood glutathione concentration and erythrocyte glutathione peroxidase activity were lower during high than during low dietary zinc intake. CONCLUSIONS: The findings indicate that an inadequate intake of zinc (45.9 micromol/d; 3 mg/d) was more effective than a moderately high intake of zinc (811 micromol/d; 53 mg/d) in inducing changes associated with a decreased copper status in postmenopausal women. Furthermore, the findings indicate that copper status indicators might be useful in evaluating changes in zinc status in humans, and an intake of 15.7 micromol (1 mg)/d of copper may be inadequate for postmenopausal women.     

Different effects of zinc and copper deficiency on composition of plasma high density lipoproteins in rats

Male Sprague-Dawley rats (six per group) were fed an egg white-based diet containing 0 or 5 micrograms/g Cu with 1, 10, 100 or 1000 micrograms/g Zn. After 6 wk of feeding, the rats were killed, and the tissues were processed for trace element, lipid and lipoprotein analysis. Copper deficiency was associated with a higher concentration of plasma free cholesterol, high density lipoprotein (HDL) cholesterol and HDL apolipoproteins. Plasma total cholesterol was not significantly affected. No significant differences were noted in HDL lipid composition. However, HDL apo E and apo A-I concentrations were higher with copper deficiency. Lecithin:cholesterol acyltransferase (LCAT) was not affected in a consistent manner by copper status. Varying the amount of zinc in the diet did not produce significant changes in plasma total cholesterol, plasma free cholesterol, HDL cholesterol, or HDL apolipoprotein concentrations. However, HDL from zinc-deficient rats were enriched in free cholesterol and depleted in triglycerides. Furthermore, the concentration of HDL apo C increased as the level of dietary zinc increased.     

The effect of zinc supplementation in humans on plasma lipids, antioxidant status and thrombogenesis

The potential exists for zinc to influence numerous metabolic functions and to impact a range of diseases. In the present review we examine the reported relationships between zinc and plasma lipids, haemostasis and other factors postulated to play a role in atherogenesis. Ecological studies that investigated zinc intake or status, and incidence of coronary heart disease (CHD) reveal no consistent pattern. The conflicting observations may be explained by differences in the extent of CHD, site of atherosclerosis, or confounding factors. In most studies the diurnal variation in serum zinc concentrations, and the lifestyle factors that affect cholesterol metabolism were not explicitly considered. Results of randomised controlled trials show that low-density lipoprotein (LDL) oxidation and the concentrations of LDL-cholesterol (c), total cholesterol and triglycerides in plasma are unaffected by supplementation with up to 150 mg Zn/d. In contrast, plasma high-density lipoprotein (HDL)-c concentrations decline when zinc supplements provide a dose >50 mg/d. Limited data suggest that sustained hyperzincaemia predisposes individuals to thrombogenesis, whereas acute zinc depletion impairs platelet aggregation and prolongs bleeding time. In addition, Zinc supplements have been shown in some studies to decrease Cu/Zn-superoxide dismutase activity, primarily due to the antagonistic relationship between high zinc intakes and copper absorption. Besides the demonstrated adverse effect of zinc supplementation on plasma HDL-c concentrations in apparently healthy men, there is insufficient evidence to determine the role of zinc supplementation in influencing other risk factors for CHD such as antioxidant status and thrombogenesis.     

Compositional changes in plasma high-density lipoprotein particles in marginally zinc-deficient male rats

This study investigated the effect of zinc status on the lipid and apolipoprotein composition of high-density lipoproteins (HDL) in adult male rats fed a semipurified diet containing a marginal level (2.8 mg/kg) of Zn as compared with the pair-fed and ad libitum-fed controls given an adequate level (30.8 mg/kg) of Zn for 7-10 wk. Compositional and chromatographic analysis of HDL fraction showed that Zn deficiency significantly lowered the total amount of circulating HDL particles with no effect on the concentrations of total protein, triglyceride, phospholipid, and cholesterol. The ratios of free: esterified cholesterol remained the same for the three groups. Electrophoretic analysis of the apolipoprotein profile showed marked decreases in the relative contents of apolipoproteins E and C and an increase in apolipoprotein (apo) A-I with no significant change in apo A-VI. No apparent morphologic aberrations of HDL particles were observed. Such changes may significantly influence the transport and metabolism of cholesterol and may provide an explanation for altered cholesterol homeostasis in Zn deficiency.     

Effect of zinc intake on copper excretion and retention in men

To determine the influence of zinc intake on copper excretion and retention, nine men consumed diets containing 2.6 mg of copper/day and 1.8, 4.0, 6.0, 8.0, 18.5 or 20.7 mg of zinc/day for one- or two-week periods in a 63-day study. Copper and zinc in the diet and copper in plasma were determined weekly; fecal copper was determined daily and averaged within each week. The weekly mean (+/-SEM) plasma copper concentrations (81 +/- 3.3 to 100 +/- 5.8 micrograms/dl) remained within the normal range throughout the study. Fecal copper and apparent copper retention were influenced by the level of dietary zinc and the duration it was fed. When 18.5 mg of zinc/day was fed for two consecutive weeks following a lower zinc intake, fecal copper was elevated and apparent copper retention was reduced after a one-week lag. Thus, an intake of zinc only 3.5 mg/day above the RDA for men reduced apparent retention of copper at an intake of 2.6 mg/day.     

Nutritional assessment of a group of Japanese elementary school children in Tokyo: with special emphasis on growth, anemia, and obesity.

Anthropometric data, nutrient intake data, and blood biochemical parameters were analyzed for 66 elementary school children living in Tokyo, Japan, and their nutritional status was evaluated focusing on three problems: (1) zinc nutriture and growth, (2) anemia with iron deficiency, and (3) lipid nutriture and obesity. The subjects' mean energy and protein intakes met the recommended levels for Japanese children. However, their zinc intake levels were inadequate at 7.2, 8.3, and 8.5 mg in grades 2 (mean age: 8 yr), 4 (10 yr), and 6 (12 yr), respectively. Mean serum zinc concentration was 0.82 +/- 0.15 microgram/ml; the percentages of subjects who showed serum zinc concentration lower than 0.68 microgram/ml, the lower limit of the normal serum zinc concentration, were 28.6, 15.4, and 5.0% in grades 2, 4, and 6, respectively. These serum zinc concentrations indicated the existence of marginal zinc deficiency in some children, particularly in grade 2, though it was not severe enough to retard growth. Their iron intake levels (8.2, 10.2, and 10.2 mg for grades 2, 4, and 6, respectively) in combination with the proportion of iron intake from animal foods (37%) were judged to be adequate because no children showed serum ferritin, serum iron, or transferrin saturation levels lower than the criteria levels recommended for iron deficiency. Moreover, no definitely anemic children were found. Daily lipid intakes were 65.7, 74.5, and 78.3 g in grades 2, 4, and 6, respectively, and the mean percentage of energy intake from lipid to total energy intake, 32%, exceeded the level recommended. Mean serum total cholesterol concentrations and the percentage of subjects with elevated cholesterol levels (greater than or equal to 200 mg/dl) were high compared with the reported values. Means of the body mass index (BMI) and Rohrer Index (RI) for the subjects were slightly higher than Japanese standards. With these parameters for obesity, triglycerides and atherogenic index were positively correlated and HDL cholesterol and HDL cholesterol percentage to total cholesterol were negatively correlated.     

The effects of dietary zinc on the activity of copper-requiring metalloenzymes in the rat

It has long been known that zinc interferes with copper absorption and metabolism. In the present study, the effects of feeding rats 15, 30, 60, 120 or 240 mg Zn/kg diet on their copper status, as assessed by the activities of cupro -zinc superoxide dismutase (SOD) and cytochrome c oxidase (CCO) in heart and liver, and ceruloplasmin (Cp) in serum were determined. Although Cp activity was not related to zinc intake in a linear fashion, the number of animals with extremely low Cp activity increased with increasing zinc. The level of zinc at which 50% of animals would have abnormally low Cp activity was calculated to be 125-129 ppm zinc. Liver SOD and heart CCO activities decreased linearly with increasing zinc and were significantly reduced compared to controls at 120 and 240 ppm Zn, respectively. Thus, animals fed zinc at levels as low as four times the AIN recommended concentration showed biochemical signs of copper deficiency.     

Copper nutriture, bioavailability, and the influence of dietary factors

Copper is known to be an essential nutrient for human beings, but a Recommended Dietary Allowance has not yet been established. A safe and adequate range of intake was established in 1980 for copper and five other trace elements. The range for copper, 2 to 3 mg/day, is higher than the usual dietary copper intake of many individuals in this country. On the basis of balance studies, a requirement of 1.3 mg/day has been suggested. Recent data on copper intake and bioavailability should aid in reevaluating the dietary copper requirement. Copper deficiency symptoms have seldom been observed in human beings. When copper deficiency has been recognized, it has been under unusual conditions, such as in patients receiving parenteral nutrition. Interactions between copper and other dietary components may alter copper status, but the impact of those interactions is not yet well understood. Dietary factors that may affect the bioavailability of copper include the levels of copper, zinc, and molybdenum in the diet; iron deficiency; ascorbic acid intake; intake of carbohydrates, including fructose, glucose, and starch; and fiber and phytate intakes. Some drugs may also affect copper bioavailability.     

Zinc supplements and serum lipids in young adult white males

A 12-wk double-blind study was conducted to determine the effect of oral zinc supplementation upon serum total cholesterol, lipoprotein-cholesterol fractions, and serum triglycerides in white males. The subjects were randomly assigned to one of three treatment groups and consumed either a placebo tablet (n = 9), 50 mg Zn/d (n = 13), or 75 mg Zn/d (n = 9) as Zn gluconate. Serum total cholesterol, low-density-lipoprotein (LDL) cholesterol, very-low-density-lipoprotein (VLDL) cholesterol, and triglycerides were not affected by Zn supplements. However, serum high-density-lipoprotein (HDL)-cholesterol levels in subjects assigned to the 75 mg Zn/d group were significantly lower at weeks 6 and 12 than those for the placebo group and lower at weeks 6, 8, and 12 than at baseline; subjects assigned to the 50 mg Zn/d group had lower serum HDL-cholesterol levels at week 12 than did the placebo group and lower at week 12 than at base line.     

Major variables of zinc homeostasis in Chinese toddlers

BACKGROUND: Measurement of the major variables of zinc homeostasis is an essential prerequisite for estimating human zinc requirements, which currently require a factorial approach. The data required for this approach have not been available for toddlers, whose requirements have been estimated by extrapolation from other age groups. OBJECTIVE: The objective of the study was to measure key variables of zinc homeostasis in rural and small-town Chinese toddlers. DESIGN: Zinc stable-isotope tracers were administered intravenously and orally with all meals for 1 d to 43 toddlers. Subsequent metabolic collections in the homes included duplicate diets, quantitative fecal collections, and spot urine sampling. Fractional absorption of zinc (FAZ) was measured by a dual-isotope tracer ratio technique, and endogenous fecal zinc (EFZ) was measured by an isotope dilution technique. RESULTS: No group or sex differences were found. Therefore, results were combined for 43 toddlers aged 19-25 mo whose major food staple was white rice. Selected results (x+/- SD) were 1.86 +/- 0.55 mg total dietary Zn/d; 0.35 +/- 0.12 FAZ; 0.63 +/- 0.24 mg total absorbed Zn/d; 0.67 +/- 0.23 mg EFZ/d; and 65.0 +/- 8.3 microg plasma Zn/dL. The molar ratio of dietary phytate to zinc was 2.7:1. CONCLUSIONS: The mean intake and absorption of zinc in this population are low in comparison with estimated average dietary and physiologic requirements for zinc, and plasma zinc values are consistent with zinc deficiency. Intestinal losses of endogenous zinc exceed previous estimates for toddlers, and only modest evidence exists of conservation in response to low zinc intake and absorption.     

Evaluation of trace trace elements iron, zinc, copper and lead in the diet of female university students

Food consumption of 50 female students in Universiti Kebangsaan Malaysia was recorded for 7 days. Foods and drinks most frequently consumed were selected for analysis of iron, zinc, copper and lead content. The mean daily intakes of energy, protein, carbohydrate and fat among the students are 6.5±1.4 MJ (1550±335 kcal), 59.8±18.5g, 227.1±54.6 g and 46.0±11.5 g respectively. This diet contributed 19.6-6.4 mg Fe, 7.0-2.0 mg Zn and 1.6-0.6 mg Cu per day which were lower than the Malaysian RDA for Fe and US RDA for Zn, while Cu is within the recommended range. The main sources of these minerals in the student's diet were rice, rice products, meat and animal products. Lead concentration in the diet (134±77 ug/day) is below the acceptable daily intake (ADI) value suggested by Codex Alimentarius Commission (1984). This study indicated concern regarding the low intake of the essential trace elements on long term basis among the students.     

北京市孕妇锌营养状况的研究

通过对270名孕妇锌营养状况的横断面研究,发现整个孕期血浆锌水平、红细胞超氧化物歧化酶(SOD)活性、血浆白蛋白水平逐渐降低;发锌在整个孕期无显著变化;血浆Cu/Zn比、血清碱性磷酸酶(ALP)活性在孕期呈逐渐升高趋势。以血浆锌<10.71μmol/L为标准,早、中、晚孕期锌缺乏的发生率分别为6.5％、20.2％、25.7％。膳食调查结果表明,北京孕妇每日膳食锌的摄入量仅为我国推荐的膳食营养素供给量(RDA)的60％左右,孕妇除维生素C及孕早期铁外,其它营养素均不同程度地低于RDA标准。并对孕期血浆锌水平降低的性质进行了讨论。     

Similar effects of zinc deficiency and restricted feeding on plasma lipids and lipoproteins in rats

The objective of this study was to determine whether alterations in HDL composition observed previously were due specifically to zinc deficiency or to reduction in food intake. Rats were placed into three groups and fed for 21 d a zinc-adequate diet (100 ppm) ad libitum, or a zinc-deficient diet (less than 1 ppm) ad libitum, or the zinc-adequate diet at an intake equal to that of the deficient group. Blood plasma was fractionated into VLDL, LDL and HDL fractions, and plasma and the isolated fractions were analyzed for lipids and apolipoprotein composition. Analysis of plasma and liver zinc indicated that animals consuming the low zinc diet were deficient. Zinc deficiency and restricted feeding were associated with lower plasma and VLDL triglyceride levels and lower HDL cholesterol levels. The similarities in overall pattern of lipoprotein composition between the zinc-deficient and restricted-intake groups indicate that reduction in food intake may account for the differences in lipoprotein composition which were observed.     

锌缺乏对初生肉仔鸡血清瘦素、下丘脑AMPK活性、神经肽Y及其mRNA水平的影响

目的研究锌缺乏对初生肉仔鸡血清和下丘脑的一些摄食相关因子的影响。方法288只1d龄AA鸡公雏按体重随机分为3组:锌缺乏组(10.1mg/kgZn)、正常组(41.8mg/kgZn)和配对组。每组8个重复,每个重复12只鸡。结果锌缺乏显著降低了肉仔鸡出壳后前2w的日增重和饲料转化率,且与日龄相关的方式影响平均日采食量(ADFI),即对前2d的ADFI无显著影响,从D3起出现显著降低。锌缺乏显著降低了血清锌、葡萄糖和瘦素水平,显著提高了下丘脑神经肽Y水平及其基因表达,而对血清胰岛素、胰高血糖素、胰岛素/胰高血糖素摩尔比及下丘脑腺苷一磷酸激活的蛋白激酶(AMPK)活性无显著影响。结论锌缺乏可使一些摄食调节因子水平及基因表达发生变化,但变化趋势与其摄食调节功能及动物采食量降低结果不相符,机制尚需研究。     

医院老年病房四季全膳食中十五种矿物质元素的测定及评价

对我院老年病房四季１１２份全膳食中的１５种元素（钾、钠、钙、磷、镁、锌、铜、铁、锰、硒、铝、钴、铬、钼、镍）进行了实测。结果表明：钾的平均日摄入量为１８０９＋３８ｍｇ，接近ＲＤＡ值的下限；钠的平均日摄入量为５９７２±１４６ｍｇ远高于１１００～３３００ｍｇ的供给标准。钙、磷、镁的日摄入量已达到了ＲＤＡ值的标准。全膳食中锌、铜的含量分别为１１．６８±０．１９ｍｇ和１．７２±０．１０ｒｎｇ，略低于ＲＤＡ值（１５ｍｇ及２～３ｍｇ）的标准，锰含量为３．４１±０．０９ｍｇ硒为９８±２．５μｇ，都处于安全与适宜摄入范围（２．５～５．０ｍｇ和５０～２００μ９）。钴、铬、钼、镍均为人体必需的微量元素、目前我国尚未建立有关营养供给量标准。该项研究结果可为今后确定其推荐供给量标准提供必要的基础资料．     

Potential antioxidant effects of zinc and chromium supplementation in people with type 2 diabetes mellitus.

OBJECTIVE: To determine the effects of combined zinc (Zn) and chromium (Cr) supplementation on oxidative stress and glucose homeostasis of people with type 2 diabetes. DESIGN: Tunisian adult subjects with HbA1C > 7.5% were supplemented for 6 months with 30 mg/d of Zn as Zn gluconate or 400 microg/d of Cr as Cr pidolate or combined Zn/Cr supplementation or placebo. The effects of supplementation on plasma zinc (Zn), copper (Cu), selenium (Se), urinary Zn, Cr, plasma thiobarbituric acid reactive substances (TBARS), Cu-Zn superoxide dismutase (SOD) and Se glutathione peroxidase (GPx) in red blood cells, blood lipids and lipoproteins, HbA1C and fasting glucose were measured at the beginning of the study and after six months. RESULTS: At the beginning of the study, more than 30% of the subjects may have been Zn deficient with plasma Zn values less than 10.7 mircomol/L, whereas levels of plasma Cu, Se and antioxidant RBC enzyme activities were in the normal ranges. Following supplementation, there were significant decreases of plasma TBARS in the Cr (13.6%), Zn (13.6%) and Zn/Cr (18.2%) groups with no significant changes in the placebo group. The value for the TBARS of the control healthy Tunisian subjects was 2.08 +/- 0.04 micromol/L and that of the Tunisian subjects with diabetes was 3.32 +/- 0.05 micromol/L. This difference of 1.24 micromol/L between the control group and the subjects with diabetes was reduced from 36% to 50% in the three supplemented groups. Supplementation did not modify significantly HbAIC nor glucose homeostasis. No adverse effects of Zn supplementation were observed on Cu status. HDL cholesterol nor interactions in Zn or Cr. CONCLUSIONS: These data suggest the potential beneficial antioxidant effects of the individual and combined supplementation of Zn and Cr in people with type 2 DM. These results are particularly important in light of the deleterious consequences of oxidative stress in people with diabetes.     

Current dietary zinc intake has a greater effect on fractional zinc absorption than does longer term zinc consumption in healthy adult men

BACKGROUND: No studies have examined the independent effects of current and longer-term dietary zinc intakes on zinc absorption. OBJECTIVE: We determined the effects of current compared with longer-term zinc intake on fractional zinc absorption (FZA). DESIGN: We studied 9 men whose usual zinc intakes were >11 mg/d. FZA was measured at baseline, depletion (0.6 mg Zn/d for 1 wk and 4 mg Zn/d for 5 wk), and repletion (11 mg Zn/d for 4 wk with 20 mg supplemental Zn/d for first 7 d). During 2 successive days after each dietary period, subjects consumed either adequate-zinc meals (11 mg Zn/d) with a zinc stable isotope tracer for 1 d, followed by low-zinc meals (4 mg Zn/d) with zinc tracer, or vice versa. Five days after oral dosing, a zinc tracer was infused intravenously. FZA was measured with the use of a modified double isotope tracer ratio method with urine samples collected on days 5-7 and 10-12 of absorption studies. RESULTS: Plasma and urinary zinc did not vary by dietary period. Mean FZA was greater from low-zinc meals than from adequate-zinc meals (60.9% +/- 13.8% compared with 36.1% +/- 8.9%; P < 0.0001), whereas mean total absorbed zinc was greater from adequate-zinc meals than from low-zinc meals (3.60 +/- 0.91 compared with 2.48 +/- 0.56; P < 0.0001), regardless of the longer-term dietary period. CONCLUSIONS: FZA was inversely related to current zinc intake, but there was no detectable effect of longer-term dietary zinc. If longer- term zinc intake does modify FZA, such changes are smaller than those caused by current zinc intake, or they occur only after more severe zinc depletion.     

缺锌对大鼠生长发育及脂代谢的影响

本文观察缺锌饲料对雄性ＳＤ幼鼠的生长、血液学多数、血清锌、碱性磷酸酶及血脂的影响。实验分五组：１组为正常对照组（饲料含锌量３２．２μｇ／ｇ）；２组为严重缺锌组（饲料合锌量３．４μｇ／ｇ），两组均自由进食；３组为锌足量组（饲料含锌８４．９μｇ／ｇ）；４组为锌缺乏组（饲料含锌４．４μｇ／ｇ）；５组为锌边缘缺乏组（饲料含锌５．５μｇ／ｇ）。后三组动物均与２组对喂。实验期２６天。结果表明：（１）严重缺锌组体重和食物摄入量显著低于正常对照组，并且出现缺锌症状，最突出的是丧失食欲；（２）严重缺锌组红细胞数、血细胞容积、血红蛋白均明显高于正常对照组，而平均红细胞容积却显著低于正常对照组，但对喂组之间未见有意义的改变；（３）严重缺锌组血清锌：碱性磷酸酶均显著低于正常对照组，而血清锌结合能力却明显高；（４）严重缺锌组血清和脂蛋白中胆固醇、甘油三酯、磷脂浓度均显著低于正常对照组，但对喂组之间差别不明显。     

Studies of nutrition and autoimmunity. Failure of zinc deprivation to alter autoantibody production when initiated in disease-established mice

Earlier studies have demonstrated that zinc deprivation, when begun in young NZB mice, can retard the development of autoimmunity and result in an increased life span. The present study evaluated the possible benefits of zinc deprivation in NZB mice with established disease, as this model is more relevant to the human patient. Female NZB mice aged 6-8 mo were fed diets containing either 80 micrograms Zn/g and 10 micrograms Cu/g (control) or 1 microgram Zn/g and 10 micrograms Cu/g (zinc-deficient) for 4 mo. In addition, another group was fed a diet containing 1 microgram Zn/g and 100 micrograms Cu/g to determine whether zinc deficiency could be exacerbated by high dietary copper through a competition of copper with zinc at the intestinal level (zinc deficient + high copper). A fourth group of mice was fed the control diet at the same intake as that of the zinc-deficient group in order to control for the inanition associated with zinc deficiency (restricted intake). Regardless of dietary treatment, all mice developed antierythrocyte antibodies at the same rate. At the end of 4 mo, 82% of the control and the restricted-intake groups had survived, whereas the zinc-deficient group had a 38% survival rate and the zinc-deficient + high copper group had a 50% survival rate. These observations show that, in contrast to findings with younger NZB mice, zinc deprivation of adult NZB mice with established autoimmunity will not improve survival. Indeed, severe zinc deficiency increased the mortality rate, demonstrating the need to consider the potential hazards of dietary extremes.     

Subject Index to Volume 10

Reduced food consumption is a major manifestation of zinc (Zn) deficiency. Many manifestations of Zn deficiency are complications of anorexia nervosa and bulimia nervosa. We evaluated serum and 24-hour urinary Zn values in 12 healthy volunteers and 33 eating disorder patients before and after hospitalization which included either Zn supplementation (75 mg Zn/day) or placebo. Bulimics had depressed serum Zn concentrations (p < 0.025). Admission urinary Zn was lower in bulimics (258 +/? 44 micrograms/day), and significantly depressed in anorexics (196 +/? 36 micrograms/day, p < 0.005) vs controls (376 +/? 45 micrograms/day). During hospitalization, serum Zn concentrations increased in all supplemented patients vs no change with placebo. Urinary Zn excretion increased in supplemented bulimics (p < 0.001) and placebo (p < 0.05). Urinary Zn excretion markedly increased in supplemented anorexics (179 +/? 65 to 1052 +/? 242 micrograms/day); however, placebo values fell or remained unacceptably low (admission 208 +/? 48 micrograms/day; discharge 160 +/? 17 micrograms/day). By dietary history, controls consumed the Recommended Dietary Allowance (RDA) for Zn (11.95 +/? 1.25 mg/day); anorexics 6.46 +/? 1.14 mg/day; and bulimics 8.93 +/? 1.29 mg/day. We suggest that Zn deficiency may act as a “sustaining” factor for abnormal eating behavior in certain eating disorder patients.