Myelopolyneuropathy and pancytopenia due to copper deficiency and high zinc levels of unknown origin II. The denture cream is a primary source of excessive zinc

Neurodegeneration of the central and peripheral nervous system associated with hypocupremia and hyperzincinemia has been widely recognized but the origin of high zinc remained unknown. Denture cream has been recently suggested as one possible source of zinc, but the frequency with which denture fixative alone accounts for this syndrome is unknown. We analyzed the origin of excessive zinc in eleven patients with a progressive myelopolyneuropathy and unexplained hypocupremia with hyperzincinemia. These patients had a detailed clinical assessment, determination of zinc and copper levels, and analyzed use of denture cream with the estimates of daily zinc exposure. We identified denture cream as a source of excessive zinc in 100% patients in our cohort. They all had a history of ill-fitting dentures requiring large amounts of denture cream, resulting in significant zinc exposure. Their copper and zinc normalized after stopping denture cream, further confirming that this is the source of high zinc. Inappropriate use of denture cream appears to be the sole source of excessive zinc in these patients.

65Zn turnover in short-term alloxan diabetic rats

65Zn was injected subcutaneously in eleven rats with alloxan diabetes of five days duration and in nine control rats. Fifty hours after the injection of 65Zn the animals were killed with an overdose of ether. In the alloxan diabetic rats signs of an altered zinc metabolism were found with an increased excretion of zinc in urine and possibly also faeces and an elevated zinc concentration in the liver compared to controls. The results also indicate an altered distribution of serum zinc in alloxan treated rats. Future studies will be necessary to demonstrate whether changes in zinc metabolism are secondary to the onset of diabetes or a primary effect of alloxan treatment.

Urinary zinc excretion during treatment with different diuretics

Urinary zinc excretion was studied in a randomized trial in 9 patients during treatment with bendroflumethiazide, chlorthalidone and hydrochlorothiazide and in another 9 patients during treatment with bumetanide, furosemide and triamterene. During treatment with the thiazides, the zinc concentration rose by 30% and the total amount of zinc excretion increased by 60%. In contrast, during treatment with the loop-diuretics, urine zinc concentration diminished and the total amount of zinc excretion increased much less than during therapy with the thiazides. With respect to the importance of zinc as an essential element in human metabolism and the frequency of diuretic treatment, the observed increased urinary losses of zinc deserve further attention.

Status of essential trace metals in biological samples of diabetic mother and their neonates

OBJECTIVE

There is accumulating facts that the metabolism of essential trace elements is altered in diabetic patients. The aim of present study was to compare the status of essential trace elements, chromium (Cr), manganese (Mn), and zinc (Zn) in biological samples (whole blood, urine and scalp hair) of insulin dependent diabetic mothers (age ranged 30-40) and their newly born infants (n = 76). An age matched 68 non-diabetic mothers and their infants, residing in the same locality, were selected as referents. For a comparative study, the biological samples of non-diabetic and diabetic pregnant and non pregnant of same age group and socio-economics status were also analysed.

METHODOLOGY

The biological samples (scalp hair, blood and urine) were collected from study and referent groups. The Cr, Mn and Zn concentrations in all three biological samples were determined by a flame/electrothermal atomic absorption spectrometer, prior to microwave assisted acid digestion. The validity and accuracy of the methodology was checked by certified reference materials (CRMs) and using conventional wet acid digestion method on same CRMs.

RESULTS

The mean values of Cr, Mn and Zn in scalp hair and blood samples of diabetic mothers and their infants were significantly lower as compared to the referent mothers-infants pairs (p < 0.01), while urinary excretion of all these elements were high in diabetic mother-infant pair samples.

CONCLUSION

The deficiencies of essential trace elements, Cr, Mn and Zn in biological samples of diabetic women, may play role in the pathogenesis of diabetes mellitus and impacts on their neonates.

Circadian characteristics of serum calcium, magnesium and eight trace elements and of their metallo-moieties in urine of healthy middle-aged men

OBJECTIVE

To monitor the around-the-clock distribution of serum and urine concentrations of calcium, magnesium and eight trace elements and of those same elements in urine after their dialysis, and to statistically describe their circadian characteristics by chronobiological procedures.

MATERIALS AND METHODS

Serum and urine samples were collected every 3h over a single 24h period from eleven clinically-healthy male subjects, 41-60 years of age, and were analyzed for calcium (Ca), magnesium (Mg), iron (Fe), copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd), cobalt (Co), chromium (Cr), and nickel (Ni). Urines were also sequentially dialyzed against ammonium-barbituric acid buffer at pH 7.35+/-0.02 using a 12.000-14.000 molecular weight exclusion sieve and then reanalyzed for the same elements. Urine concentrations were adjusted by urine volume to reflect a 3h excretion rate. Time-series were analyzed for circadian time-effect by ANOVA and for rhythm characteristics by the single cosinor fitting procedure.

RESULTS

The dialysis effectively removed 90% of total solids, 97% of urea, 92% creatinine, 72% uric acid, and essentially all of glucose. It also removed 99% of potassium (K), 96% of sodium (Na), 65% of Ca and P, 55% of Mg, 41% of Zn and 88% of Ni. A significant or borderline-significant 24h rhythm in serum was detected for Ca, Mg, Fe, Cu, Zn, Cd and Cr; in untreated urine for Ca, Fe, Cu, Zn, Ni, creatinine and volume; and in dialyzed urine for Ca, Fe, Cu, Zn, Pb, Cr, Cd and Ni. A 12h component was significant or borderline-significant in serum for Mg, Fe, Zn, and Cd; in untreated urine for volume, creatinine, Ca, Mg, Cu, and Ni; and in dialyzed urine for Ca, Mg, Fe, Cu, Zn, and Cr. In general, values in serum were lowest near the onset of sleep and highest in the first half of the day (between 02:28 and 13:56 h), while highest values in untreated or dialyzed urine were found several hours later in the day and at night.

CONCLUSIONS

Significant circadian variations were found in levels of nearly every element that was measured in blood and urine of 11 healthy men, but with highest and lowest levels occurring at different times. This suggests not only that urine concentrations need to be adjusted for collection time interval and urine volume, but that different biological limits at different times of the 24h day should be applied for serum and urinary monitoring of trace elements. We also found that the non-dialyzable segments of these elements in urine represent metallo-moieties composed of proteinacious matter greater than 12,000-14,000 Daltons. Further studies would be of interest to reveal time specificity for metabolic functions associated with any of these trace elements.

Investigation on health effects of an abandoned metal mine

To investigate potential health risks associated with exposure to metals from an abandoned metal mine, the authors studied people living near an abandoned mine (n=102) and control groups (n=149). Levels of cadmium, copper, arsenic, lead, and zinc were measured in the air, soil, drinking water, and agricultural products. To assess individual exposure, biomarkers of each metal in blood and urine were measured. beta2-microglobulin, alpha1-microglobulin, and N-acetyl-beta-glucosaminidase and bone mineral density were measured. Surface soil in the study area showed 2-10 times higher levels of metals compared to that of the control area. Metal concentrations in the groundwater and air did not show any notable differences between groups. Mean concentrations of cadmium and copper in rice and barley from the study area were significantly higher than those of the control area (p<0.05). Geometric means of blood and urine cadmium in the study area were 2.9 microg/L and 1.5 microg/g Cr, respectively, significantly higher than those in the control area (p<0.05). There were no differences in the levels of urinary markers of early kidney dysfunction and bone mineral density. The authors conclude that the residents near the abandoned mine were exposed to higher levels of metals through various routes.

Trace element levels in adult patients with proteinuria

AIM

Trace elements are involved in many metabolic processes. They circulate prevalently bound to protein. In literature few studies deal with metal metabolism in adult patients with proteinuria, so we decided to further investigate metal metabolism in proteinuric patients.

METHODS

We studied 27 patients (14 male, 13 female), mean age 61.6+/-17 years with different degrees of renal function, serum albumin and proteinuria. Metal concentrations of copper (Cu), zinc (Zn) and aluminum (Al) were measured in serum and urine. No patient had environmental exposure to these metals.

RESULTS

The serum Zn level was below the normal range in 11 patients. The serum Cu level was reduced in 5 patients. The Al serum level was elevated in 4 patients. Six patients had reduced and 6 patients had elevated Zn excretion. The urinary Cu excretion was elevated in 6 patients. The urinary Al excretion was elevated in 1 patient. Trace metal concentrations were related neither to renal function nor to total serum protein or albumin levels. Serum zinc was directly correlated with proteinuria and urinary zinc and negatively correlated with testosterone levels in both sexes.

CONCLUSION

Adult patients with proteinuria have several modification of trace metal concentration in serum and urine. Serum concentration of metals did not depend on renal function or serum protein levels. Urinary Zn excretion was directly related to proteinuria and serum Zn levels. A negative correlation between serum Zn levels and testosterone was found in both sexes. Renal failure reduced urinary excretion of Cu and Al.

Serum testosterone and urinary excretion of steroid hormone metabolites after administration of a high-dose zinc supplement

OBJECTIVES

To investigate whether the administration of the zinc-containing nutritional supplement ZMA causes an increase of serum testosterone levels, which is an often claimed effect in advertising for such products; to monitor the urinary excretion of testosterone and selected steroid hormone metabolites to detect potential changes in the excretion patterns of ZMA users.

SUBJECTS

Fourteen healthy, regularly exercising men aged 22-33 years with a baseline zinc intake between 11.9 and 23.2 mg day(-1) prior to the study.

RESULTS

Supplementation of ZMA significantly increased serum zinc (P=0.031) and urinary zinc excretion (P=0.035). Urinary pH (P=0.011) and urine flow (P=0.045) were also elevated in the subjects using ZMA. No significant changes in serum total and serum free testosterone were observed in response to ZMA use. Also, the urinary excretion pattern of testosterone metabolites was not significantly altered in ZMA users.

CONCLUSIONS

The present data suggest that the use of ZMA has no significant effects regarding serum testosterone levels and the metabolism of testosterone in subjects who consume a zinc-sufficient diet.

The effect of Roux-en-Y gastric bypass on zinc nutritional status

BACKGROUND

Researchers have found that zinc nutritional status in obese and diabetic subjects is altered: low zinc concentrations in plasma and erythrocytes, with high urinary zinc excretion, were observed. This study evaluated the effect of Roux-en-Y gastric bypass (RYGBP) on plasma, erythrocyte and urinary zinc concentration.

METHODS

22 morbidly obese patients were studied before and 6 months after RYGBP. Fasting blood sample and 24-hour urine were collected in the pre- and postoperative phases. A software analyzed the diet information from 3-day food records after RYGBP. Zinc nutritional status was evaluated by determination of the concentration of this mineral in plasma and erythrocytes, and the urinary excretion of zinc / 24 hours by atomic absorption spectrophotometry.

RESULTS

The diets consumed by the patients had adequate average concentrations of zinc. Zinc concentration in plasma, erythrocytes and urine were within the values of normality before RYGBP, with mean values of 93.25 +/- 19.34 microg/dL, 43.85 +/- 7.76 microg Zn/gHb and 583.05 +/- 359.30 microg Zn/24 hours, respectively. At 6 months after RYGBP, there was a change in these parameters to 69.82 +/- 10.95 microg/dL, 51.80 +/- 6.92 microg Zn/gHb, 535.29 +/- 216.40 microg Zn/24 hours in the concentration of plasma, erythrocyte and urinary zinc.

CONCLUSION

These results suggest that RYGBP promoted, besides change in body composition, an alteration in the zinc plasma and erythrocytes concentrations which in the medium and long term, could cause problems for these patients.

Serum, urinary and stone zinc, iron, magnesium and copper levels in idiopathic calcium oxalate stone patients

Many theories have been put forward to explain the mechanism of stone formation and growth. The aim of this study was to investigate the urinary, serum and stone levels of zinc, iron, magnesium, and copper in patients with calcium oxalate stones and to investigate urinary and serum element levels in healthy controls and to find a possible connection between the elements and calcium oxalate stone formation. A total of 104 patients with calcium oxalate stones ranging in age from 3 to 79 years (mean 44.0 +/- 18.1) and 77 healthy controls ranging in age from 18 to 77 (mean 44.2 +/- 17.9) were included in this study. The mean urinary iron and copper levels in stone patients were significantly higher than healthy controls (P = 0.000). The mean urinary zinc and magnesium levels in healthy controls were significantly higher than stone patients (P = 0.000). There was no significant difference in the serum levels of magnesium and copper in stone patients and healthy controls. Serum zinc and iron level were significantly high in healthy controls as compared to stone patients. Each stone had all 4 elements. Zn and Mg have inhibitory effect on calcium oxalate stone formation. Fe and Cu could be promotor of the calcium oxalate stone formation.

Levels of calcium, magnesium and zinc in urine among adult women in relation to age with special reference to menopause

OBJECTIVES

This study was initiated to examine, on a basis of large-scale epidemiology, if urinary calcium (Ca), magnesium (Mg) and zinc (Zn) levels change as a function of age and menopause.

METHODS

Spot urine samples were collected from adult women, and analyzed for the minerals. Additional information e.g. on smoking habits was obtained by questionnaires, so that cases were classified into 10,464 never-smokers, 1,351 current smokers and 343 past smokers. The mineral concentrations were evaluated as observed (e.g. Ca-U(ob)), and after correction for creatinine (CR) concentration (e.g. Ca-U(cr)) or specific gravity (SG) (e.g. Ca-U(sg)).

RESULTS

Analyses with never-smokers showed that age-dependent changes in Ca-U(ob), Mg-U(ob) and Zn-U(ob) were minute. Menopause induced a small increase in Ca-U(ob) and a small decrease in Zn-U(ob). Values after CR or SG correction were increased in accordance with both age and menopause, possibly due to age- and menopause-associated decreases in urine density.

CONCLUSIONS

Ca-U(ob), Mg-U(ob) and Zn-U(ob) did not vary substantially throughout life. Ca-U(ob) and Zn-U(ob) were slightly higher and lower, respectively, in post-menopausal women than in pre-menopausal women, but such changes were too small to affect life-long stabilities. Thus, the urinalyses did not suggest need of additional supply of Ca, Mg or Zn at advanced ages. Correction for CR or SG may induce a bias in evaluation of age-dependent changes in mineral concentrations, because CR and SG decrease in accordance with age.

Twenty-nine year study on circadian distribution of urinary zinc levels of same male subjects

OBJECTIVES

To examine the circadian distribution and total 24h levels of urinary zinc (Zn) in same male subjects over an extended period of time in order to ascertain their relationship with aging.

MATERIALS AND METHODS

Eight young army volunteers served as subjects over a period of 29 years: 1969, 1979, 1988, 1998. By 1979 three of them became latent diabetics. Complete physical examination, anthropometric measurements and same procedural protocol was followed in each study. Samples were collected over 3 hour periods for 24 hours in the middle of each month of May. Urine aliquots were analyzed for creatinine, using conventional laboratory procedure. Zn was analyzed using Atomic Absorption Spectrophotometry in 1969, and 1979 and by Inductively Coupled Plasma, in 1988 and 1998.

RESULTS

Over the course of 29 years the circadian distribution of Zn was altered by decrease in amplitude in Zn levels, while the 24h concentrations of Zn decreased progressively with increasing age in healthy and diabetic subjects: Healthy; 966+/-130 microg at age of 29; 666+/-14 microg at 39; 511+/-80 microg at 48; and 555+/-71 microg at age of 58y; Diabetics exhibited similar trend; 1757+/-60 microg at age 28; 1253+/-40 microg at age 38, 1132+/-31 microg at 47, and 1025+/-11 microg at the age of 57. Anthropometric measurements in each study period revealed significant increases in diabetic subjects for body weight, body surface area, BMI and significant decrease in body heights of both groups.

CONCLUSIONS

The daily excretion of urinary Zn over the 29 years period decreased by 42% in healthy and diabetic subjects. Although there appears to be a lack of a reliable index of intracellular Zn status to accurately monitor and control zinc deficiency in younger and older populations, the present data suggest that depletions of Zn are also evident in healthy aging subjects whose daily diet was not deficient in zinc.

Zinc homeostasis in 1–4 year olds consuming diets typical of US children

Few data have evaluated Zn balance in young children after the first year of life. The objective of the present study was to study the relationships among Zn intake, absorption, endogenous faecal excretion, and retention in a group of healthy children. Thirty children, aged 15–48 months, were studied on a diet representative of their usual daily mineral intake. Zn absorption was assessed using a dual-tracer stable-isotope technique. Endogenous Zn faecal excretion and Cu absorption were determined in a subset of children. We found that Zn intake from the in-patient weighed dietary record (5·0 (sd 2·1) mg/d) was significantly greater than the current estimated average requirement (EAR; 2·5 mg/d; P < 0·0001). Neither fractional Zn absorption, urinary Zn excretion, nor endogenous faecal Zn excretion was significantly related to Zn intake (r2 < 0·1; P>0·4, for all). Absolute Zn absorption was significantly related to Zn intake (r2 0·696; P < 0·0001), as was Zn retention (r2 0·506; P < 0·0001). Cu absorption was relatively high (75·1 (sd 10·8) %) despite the high Zn intake. The EAR for Zn based on this dataset would appear to be between 4·2 and 4·7 mg/d to allow for a net average retention of 120 μg/d consistent with growth needs. We concluded that at relatively high Zn intakes there was little evidence of down regulation of absorption or up regulation of urinary or endogenous faecal Zn excretion across the intake range studied. Zn retention was positively correlated with intake. A Zn intake between 4·2 and 4·7 mg/d should meet the requirement for normal growth for this age group.

Zinc dyshomeostasis in rats with aldosteronism. Response to spironolactone

Zinc is a structural constituent of many proteins, including Cu/Zn superoxide dismutase (SOD), an endogenous antioxidant enzyme. Hypozincemia has been found in patients hospitalized with congestive heart failure, where neurohormonal activation, including the renin-angiotensin-aldosterone system (RAAS), is expected and oxidative stress is present. This study was undertaken to elucidate potential pathophysiological mechanisms involved in Zn dyshomeostasis in aldosteronism. In rats receiving aldosterone/salt treatment (ALDOST) alone for 1 and 4 wk or in combination with spironolactone (Spiro), an ALDO receptor antagonist, we monitored 24-h urinary and fecal Zn excretion and tissue Zn levels in heart, liver, and skeletal muscle, together with tissue metallothionein (MT)-I, a Zn(2+)-binding protein, and Cu/Zn-SOD activities in plasma and tissues. When compared with unoperated, untreated, age-/sex-matched controls, urinary and, in particular, fecal Zn losses were markedly increased (P < 0.05) at days 7 and 28 of ALDOST, leading to hypozincemia and a fall (P < 0.05) in plasma Cu/Zn-SOD activity. Microscopic scars and perivascular fibrosis of intramural coronary arteries first appeared in the right and left ventricles at week 4 of ALDOST and were accompanied by increased (P < 0.05) tissue Zn, MT-I, and Cu/Zn-SOD activity, which were not found in uninjured liver or skeletal muscle. Spiro cotreatment prevented cardiac injury and Zn redistribution to the heart. Thus increased urinary and fecal Zn losses, together with their preferential translocation to sites of cardiac injury, where MT-I overexpression and increased Cu/Zn-SOD activity appeared, contribute to Zn dyshomeostasis in rats with aldosteronism, which were each prevented by Spiro. These findings may shed light on Zn dyshomeostasis found in patients with decompensated heart failure.

Effect of zinc supplementation on in vitro copper-induced oxidation of low-density lipoproteins in healthy French subjects aged 55–70 years:the Zenith Study

Zn has been shown to possess antioxidant properties in vitro and in vitro. As inadequate dietary Zn intake has been reported in these populations, Zn supplementation may protect against oxidative stress and thereby limit the progression of degenerative diseases in such populations. We conducted the present study to evaluate the long-term supplementation effects of two moderate doses of Zn on in vitro Cu-induced LDL oxidation in French men and women.Three groups of sixteen healthy subjects aged 55–70 years from each sex participated in this randomized double-blind, placebo-controlled study. Each group received for six months either 0, 15 or 30mg supplemental Zn per d. At the beginning and at the end of the supplementation periods, dietary intakes of Zn, Cu, Fe and vitamin E were estimated using 4d food-intake records (including the weekend) and the GENI program. Zn, Cu, Fe and vitamin E statuswere also determined. In vitro LDL oxidizability (basal conjugated diene level, maximal conjugated diene formation and lag time) and lipid parameters were also determined. Dietary intakes of Zn, Cu, Fe and vitamin E were adequate in this population. Zn supplementation significantly increased serum Zn levels but did not significantly modify Cu, Fe or vitamin E status. However, Zn supplementation had no effect on in vitro LDL oxidation parameters, nor were there any sex-related differences in in vitro LDL oxidizability. The present study showed that long-term Zn supplementation of healthy subjects aged 55–70 years had no effect on in vitro Cu-induced LDL oxidation under the study conditions.

Comparison of urinary amino acids and trace elements (copper, zinc and manganese) of recent neurolathyrism patients and healthy controls from Ethiopia

OBJECTIVE

The irreversibly crippling disease neurolathyrism is caused by prolonged over-consumption of Lathyrus sativus seed. The molecular mechanism of toxicity is unclear and more biochemical information is needed.

METHODS

The urinary amino acids from 5 recent patients and 9 healthy subjects in Ethiopia were analysed by HPLC after PITC (phenyl isothiocyanate) derivatisation. The trace elements Cu, Zn and Mn of urine and seeds were determined by atomic absorption spectroscopy.

RESULTS

The free amino acids aspartic acid, glycine, beta-aminoisobutyric acid, arginine, alpha-aminoadipic acid and phenylalanine were statistically higher (p<0.05) in urine from patients than in urine from control subjects. The trace element Cu was also statistically higher (p<0.05) in patient urine.

CONCLUSION

The amino acid metabolism of the neurolathyrism patients is disturbed by over-consumption of grass pea seeds. The high concentrations of Cu found in the patient urine might indicate the involvement of trace elements in the aetiology of neurolathyrism.

[Effect of zinc deficiency on effectiveness of the treatment of liver encephalopathy in patients with liver cirrhoses]

Zinc plays an important role in human physiologic processes being cofactor of many enzymes, it participates in numerous enzyme reactions. We have investigated 15 patients with liver cirrhoses of different etiology. With the rising of class of liver impairment and developing liver encephalopathy, level of zinc in blood drops. Treatment with diuretic therapy results in increase of discharge of zinc with urine and prevents recovery of its level in blood.

Effects of angiotensin-converting enzyme inhibitors (ACE i) on zinc metabolism in patients with heart failure

The aim of this study is to investigate the effects of angiotensin-converting enzyme (ACE) inhibitors and furosemide on zinc metabolism by assessing serum zinc and urine levels in hospitalized subjects. We recruited 11 patients with heart failure from the Internal Medicine Department; these patients had been hospitalized less than 72 h before. Heart failure was defined using clinical and radiological signs. Serum zinc concentrations were measured using an air/acetylene flame atomic absorption spectrophotometer. Urine zinc levels were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Data were obtained from the 11 patients and 24 healthy controls matched for age and sex. Results indicate higher urine zinc levels and lower concentrations of zinc in serum in heart failure patients vs matched controls (p<0.05). This study suggests that treating heart failure patients with ACE inhibitors may result in zinc deficiency.

Urinary excretion of zinc and metabolic control of patients with diabetes type 2

The objective of this study was to assess urinary excretion of zinc and evaluation parameters of metabolic control in type 2 diabetic patients. Thirty-one type 2 diabetic patients, of both genders, with 5.8 +/- 5.6 years average time of the disease, age range 20-60 years, were selected. Evaluation of the nutritional status was performed using anthropometric measurements. To evaluate food consumption, the 3-day alimentary log method was used, and its analysis was performed using a software. Determination of urinary zinc was by atomic absorption spectrophotometry. From the obtained results, it was concluded that 51.6% of the patients were overweight. The mean of found waist circumference was 100.4 and 92.2 cm for men and women, respectively. Blood glucose and glycated hemoglobin values were higher than reference values, and plasma albumin concentration was adequate. The median of found urinary zinc excretion was 474.9 mug/24 h, within normal standards (300-600 mug/day). Regarding diet composition, calorie and protein concentration were above recommendation, while mean zinc concentration was adequate. This data allow the conclusion that the evaluated patients presented adequate urinary zinc excretion in comparison with reference values.

Clinical evaluation of the bioavailability of zinc-enriched yeast and zinc gluconate in healthy volunteers

Zinc (Zn)-enriched yeast and gluconate are considered two of the more biologically available supplements. However, there have been few reports comparing the bioavailability of these supplements. The objective of this study was to demonstrate whether Zn was absorbed better by healthy male volunteers when given supplements where the mineral is found organically bound in yeast or as a salt gluconate form. The trial used a randomized, two-way crossover design. Urine, blood, and fecal samples were collected and analyzed over a 48-h period after a single dose of supplement. The net Zn balance and the relative bioavailability were calculated. No differences were observed in urine excretion of the two supplements. Zinc gluconate gave higher Zn concentrations in the blood in the first 6 h but also showed greater losses in the feces. Zinc yeast also increased in blood with time but showed significantly less loss in the feces. Thus, the net Zn balance after 48 h for Zn yeast was 9.46 but for Zn gluconate it was -2.00, indicating that Zn gluconate supplementation contributed to a net loss of Zn. It was concluded that organic Zn yeast supplements are more biologically available than Zn gluconate salts.

Effect of high-dose iron supplements on fractional zinc absorption and status in pregnant women

BACKGROUND

Women have an increased risk of iron deficiency during pregnancy because of the demands of the developing fetus. Iron supplements are commonly advocated as a prophylactic treatment and are generally taken with meals to reduce side effects, but iron can interfere with the absorption of zinc.

OBJECTIVE

The aim was to determine the effect of consuming an iron supplement (100 mg Fe/d as ferrous gluconate) with meals from 16 wk gestation to term on zinc status and absorption.

DESIGN

Stable-isotope techniques were used to measure zinc status (exchangeable zinc pool, EZP) and fractional zinc absorption (FZA) in early and late pregnancy from a meal consumed at a different time from that of iron supplement or placebo consumption in 6 women given iron supplements and 7 given a placebo.

RESULTS

FZA increased during pregnancy, independent of iron supplementation. FZA was significantly higher (P < 0.001) at week 34 than at weeks 16 and 24, and urinary zinc excretion was higher at week 34 than at week 16 (P = 0.02). The size of the EZP remained unchanged throughout pregnancy and was unaffected by iron supplementation. The iron status of iron-supplemented women was higher than that of the placebo group.

CONCLUSIONS

In iron-replete pregnant women who consumed a Western diet, no detectable adverse effects on zinc metabolism were observed after ingestion of 100 mg Fe/d. An increase in the efficiency of zinc absorption was observed during late pregnancy.

Mineral factors controlling essential hypertension--a study in the Chandigarh, India population

Essential hypertension (EH) is a major public health problem world over and in India. Recent data on EH in the population of Chandigarh (Union Territory and capital of Punjab and Haryana States of India) revealed that the prevalence of EH has become double in the last 30 years in the residents of Chandigarh (26.9 to 45.80% in the year 1968 and 2002). Zinc (Zn), copper (Cu), magnesium (Mg), and manganese (Mn) in the serum are considered important in maintaining the human hypertension. The high Zn intake was considered to increase the blood pressure (BP) and to affect the other mineral status in the body. Recent survey on the trace metal status of different vegetables in the State of Punjab around Chandigarh (India) revealed that Zn level is significantly higher (40 mg/kg or more in above ground vegetables and 120 mg/kg or above in underground vegetables) in underground water-irrigated vegetables, but the levels of Cu and Mg are within prescribed limit. The present study was conducted on Chandigarh population to evaluate the levels of Zn, Cu, Mg, and Mn in the blood and urine of normotensive (NT) control and hypertensive (HT) subjects matched with number, age and sex. Atomic absorption spectrophotometer studies reevaluated that the levels of serum Zn, Mg, and Mn were significantly higher (p < 0.001), but the level of Cu was low in the HT subjects (BP = 160/93) compared to NT control (BP = 140/83). Higher levels of urinary Zn, Cu, Mg, and Mn were observed in the HT subject vs NT control (p < 0.001). Positive correlations were evaluated between the levels of serum Zn, Mg, and Mn vs systolic and diastolic pressures (DP and SP), respectively (r = 0.928, 0.863, 0.876, 0.808, 0.404, 0.326, p < 0.01), but negative and positive nonsignificant correlations between the serum Cu with SP and DP were recorded (r = -0.032, r = 0.024). Positive correlations were also evaluated between urinary levels of Zn, Cu, Mg, and Mn vs SP and DP (r = 0.718, 0.657, 0.750, 0.681, 0.630, 0.578, 0.516, 0.461, p < 0.01). Prevalence of essential hypertension may be due to higher Zn level in the food chain that makes the individuals vulnerable to other diseases over the time related to essential hypertension.

Exchangeable zinc pool size at birth is smaller in small-for-gestational-age than in appropriate-for-gestational-age preterm infants

BACKGROUND

Small-for-gestational-age (SGA) infants are susceptible to postnatal zinc deficiency, but whether this susceptibility is due to intrauterine factors or to high postnatal growth requirements is unknown.

OBJECTIVE

We hypothesized that the size of the exchangeable zinc pool (EZP), which reflects metabolically available zinc, would be smaller in SGA than in appropriate-for-gestational-age (AGA) infants born prematurely.

DESIGN

Intravenous 70Zn (45 microg/kg) was administered to 10 SGA infants (8 boys) with a mean (+/-SD) gestational age of 33.3 +/- 1.8 wk and to 11 AGA infants (8 boys) with a mean (+/-SD) gestational age of 32.4 +/- 1.2 wk within 24 h of birth. The EZP was determined from isotope enrichment in spot urine collections on days 3-7.

RESULTS

The mean birth weight of the SGA infants was 1.30 +/- 0.2 kg and of the AGA infants was 1.84 +/- 0.3 kg (P = 0.0001). The EZP size was significantly smaller in the SGA than in the AGA infants on an absolute basis (13.3 +/- 2.8 and 25.2 +/- 8.1 mg; P = 0.0002) and relative to body weight (10.3 +/- 2.5 and 13.9 +/- 4.5 mg/kg; P = 0.02). The difference remained significant after adjustment for gestational age and birth weight.

CONCLUSION

These data provide evidence for differential zinc status at birth between SGA and AGA infants born prematurely at similar stages of gestation and offer at least a partial explanation for the reported benefits of postnatal zinc supplementation.