Negative Zinc Balance Research Articles

The effect of Zinc on the growth of preterm baby in Baghdad, Iraq

Background: Zinc is an essential trace nutrient, has important function to play in growth. Many studies have indicated that a negative Zinc balance exist in preterm and small for gestational age infants until approximately 37 weeks of gestation. Several workers have recorded an improved Zinc status, good weightgain and better linear growth velocities in preterm infants supplement with Zinc. Aim of study: The current study evaluates the effect of zinc supplementation on growth parameters of premature infants. Also to determine the role of zinc therapy in treatment of acute diarrhea in children aged 3 months - 2 years. Methods: This randomized clinical trial study was done in Imamein Kadhemain Medical City, pediatric department, in the period from 1st December 2013 to 30th july2014. One hundred hospital born preterm infant with gestational age <37 weeks, whose were admitted to the hospital , when they were ready for discharge ,they randomly assigned to receive Zinc & multivitamins (50 neonates) ormultivitamins only (50 neonates). Multivitamin are vitamin A, vitamin D, iron & folic acid. The Zinc group received it in a dose of2 mg/kg/day. Weight, length and head circumference were followed up after 4 weeks. Results: In this study no significant difference in weight, length and head circumference between the zinc group & control group at the start but a significant difference were found at 4 weeksfollow up (P<0.05). Conclusion: Zinc supplementation for preterm babies was found effective to enhance the growth in early weeks of life, while in regard to difference in growth according to types of feeding there is no significant difference.

Transient zinc deficiency in preterm infants

Zinc is an essential element and necessary for various cellular functions. Preterm infants may have a negative zinc balance and are therefore especially susceptible for symptomatic zinc deficiency. We report on a preterm child with distinct clinical manifestations of zinc deficiency confirmed by histology and laboratory analysis who quickly healed with oral zinc therapy.

Effect of Dietary Phytate on Zinc Homeostasis in Young and Elderly Korean Women

Background: Previous studies suggest that consumption of predominantly plant-based diets with high phytate content contribute to zinc deficiency by inhibiting zinc absorption. Age of the individual may also affect the ability to maintain zinc homeostasis.Objective: This study was designed to determine the effect of dietary phytate on zinc homeostasis and to evaluate the effect of age on the capacity to maintain the zinc homeostasis with changes in dietary phytate in young and elderly Korean women.Design and Methods: Seven healthy young women (22–24 yr) and 10 healthy elderly women (66–75 yr) were studied consecutively for 3 months in 2 metabolic periods (MP) in two different metabolic units. During MP1 the women consumed a high phytate (HP) diet (P:Zn molar ratio = 23) for 9 days. After a 10 d wash-out period at home eating their usual diets, a lower phytate diet (LP) (P:Zn molar ratio = 10) was fed in MP2 for 9 d. Phytase was added to selected foods in the high phytate diet to reduce the phytate content of the meals in the LP period. The zinc content of both diets was about 6.5 mg/d. Stable isotopes of Zn (70Zn) were administered intravenously on d 5 of MP 1 and 2 for measuring endogenous fecal zinc excretion. Plasma samples were also collected on d 5 for measuring plasma zinc concentrations by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). 24 hr urine samples were collected for 5 d and complete fecal samples were collected for 9 d after isotope administration. Fractional zinc absorption (FZA) was calculated from mass balance corrected for endogenous fecal zinc (EFZ) excretion and EFZ was determined by using an isotopic dilution technique. Isotopic ratios for FZA and EFZ were measured by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Statistical analyses were done using ANOVA.Results: Both the young and elderly women were in negative zinc balance during the HP period. This was due to a significant decrease in FZA and total absorbed zinc (TAZ) with a HP diet (43 vs 22% in young women, 34 vs 20% in elderly women, p < 0.001). EFZ excretion did not differ in the young and elderly women during the LP and HP periods. Dietary phytate did not alter plasma zinc concentrations or and urinary zinc excretion in either group.Conclusions: Adjustments in zinc homeostasis with an increase in dietary phytate did not differ between young and elderly women in this study.

Zinc concentration in patients with iron overload receiving oral iron chelator 1,2-dimethyl-3-hydroxypyrid-4-one or desferrioxamine.

To determine the changes in serum zinc concentration and the extent of urinary zinc excretion in patients with iron overload receiving the oral iron chelator 1,2-dimethyl-3-hydroxypyrid-4-one (L1) or desferrioxamine (DFX), and to correlate these results with blood glucose concentration. Serum zinc and ferritin concentrations, urinary zinc and iron excretion were regularly assayed in 39 patients and the glucose tolerance test (GTT) was performed in each patient. Patients were segregated according to their GTT into normal, diabetic, and those with an abnormal GTT. The mean of L1- or DFX associated urinary zinc excretion for each group was determined and compared with the other two groups and with normal value. L1 associated urinary zinc excretion was also compared with L1 dose, serum ferritin values, and urinary iron excretion. Both DFX and L1 were associated with a significantly increased urinary zinc excretion (15.1 (7.3) mumol/24 hours, 11.1 (6.0) mumol/24 hours, respectively) compared with normal subjects. In patients receiving DFX this increase only occurred in patients with diabetes mellitus. Both diabetic and non-diabetic patients receiving L1 treatment excreted more zinc than normal. Diabetic patients receiving L1 or DFX excreted more zinc than non-diabetics receiving the same treatment. No correlation was found between urinary zinc excretion and L1 dose or patients' serum ferritin concentrations. In seven patients receiving long term L1 treatment a fall in serum zinc was observed from an initial 13.6 (1.6) mumol/l to a final 9.6 (0.8) mumol/l. In one patient this was associated with symptoms of dry skin and itchy skin patches requiring treatment with oral zinc sulphate. In contrast to DFX, L1 treatment is associated with increased zinc loss. This, however, is modest and does not lead in most patients to subnormal serum zinc concentrations. In a few patients whose negative zinc balance may give rise to symptoms, zinc supplementation rapidly corrects the deficit.

Zinc and Chronic Renal Disease

SummaryHypozincemia is common in patients with hronic renal insufficiency, and in patients with ESRD treated with peritoneal and hemodialysis. The causes of the decreased plasma zinc concentration in these patients are not completely understood, but poor nutritional zinc intake, diets associated with attempts to prevent the progression of renal failure, prescribed mineral supplements and medications, hypoalbuminemia, diminished gastrointestinal zinc absorption, increased urinary zinc excretion and redistribution of zinc into the intracellular fluid may all affect extracellular fluid zinc concentration and total body zinc stores in patients with chronic renal insufficiency. Zinc intake is probably the most important determinant of total body zinc status and plasma zinc concentration in these patients. The extent of true zinc depletion in this population is unknown, but it is likely to be an important problem.Patients with ESRD treated with hemodialysis may have similar reasons for developing hypozincemia, although it is unlikely that urinary losses play an important role in the development of negative zinc balance in this group. Although there is little evidence that hemodialysis results in net zinc losses, treatment effects may result in the redistribution of zinc from the extracellular fluid, resulting in the development of hypozincemia. Because such patients appear to be susceptible to the development of negative zinc balance due to gastrointestinal zinc losses, it would seem that they require increased levels of zinc intake. The similarity of the symptoms of zinc deficiency and uremia have prompted several studies of the effects of zinc supplementation on taste acuity, sexual, immune and neurologic function in hemodialysis patients, with some positive results.Patients with ESRD treated with CAPD may have hypozincemia as well, for reasons similar to those suggested in patients treated with hemodialysis. De‐spite protein losses in the peritoneal dialysate, net influx of zinc occurs during peritoneal dialysis.Since zinc deficiency may mediate some symptoms of uremia in patients treated for ESRD, clinicians should consider measuring circulating zinc concentration and providing therapeutic supplementation with zinc salts to hypozincemic patients with abnormalities of taste, sexual and immune function. Studies which have demonstrated a beneficial effect of zinc supplementation have used daily doses of 50 mg of zinc, given as zinc acetate, zinc chloride, or zinc sulfate. Zinc sulfate ingestion has been associated with gastrointestinal side effects. Zinc chloride has been added to dialysate in chronic studies to achieve a final zinc concentration of 400 μg/L, with beneficial results. The proper route, amount and length of such therapies, however, are currently unknown. Whether one zinc compound has clinical advantages compared to others must also await con‐trolled clinical evaluation.

Hepatic metallothionein as a source of zinc and cysteine during the first year of life.

Metallothionein, a high cysteine-containing protein, can bind with both essential and nonessential metals and thus play an important role as a metal storage protein and also in the detoxification of toxic metals. Although in the human fetus, levels of trace minerals and metallothionein are very high, their postnatal changes are not well documented. The purpose of the present investigation, therefore, was to quantify the accumulation of metallothionein in premature and full-term infants during the first year of life and to identify factors affecting its accumulation. From 47 postmortem samples, it was determined that hepatic metallothionein levels were highest in newborn premature and full-term infants falling to levels found in older children by 4.4 months of age. Hepatic zinc levels were also highest in the youngest infants, falling with increasing postnatal age. There was a significant positive correlation between zinc and metallothionein at all ages. However, there was a negative correlation between hepatic metallothionein levels and cystathionase activity. Hepatic copper and metallothionein levels were unrelated. The renal concentration of metallothionein, zinc, and copper were significantly lower than corresponding hepatic levels. The fall in hepatic levels of zinc and metallothionein during the first months of life correspond to a period of negative zinc balance and low endogenous cysteine production in the newborn. Thus metallothionein may play an important role as a storage depot for these two essential nutrients during this critical period of active growth.

Zinc balance in combined zinc deficiency and uremia

In order to evaluate whether the hypozincemia associated with chronic renal failure represents true negative zinc balance, male Lewis rats were randomized and pair-fed zinc replete (+Zn) or deplete (-Zn) diets. Subsequently, each animal underwent one- and two-thirds nephrectomy, or a sham operation. Complete balances for zinc, calcium, and magnesium were determined weekly before and after nephrectomy. At sacrifice, -Zn animals had significantly lower (P less than 0.005) plasma zinc levels compared to controls. Nephrectomized (N) animals had significantly elevated plasma creatinine (P less than 0.005), diminished creatinine clearances (P less than 0.005), and increased urinary flows (P less than 0.005) and protein excretion (P less than 0.01) compared to sham-operated (S) controls. Zinc nutritional status had no effect on these parameters in animals with comparable renal function. -Zn/N animals had consistently significantly elevated (P less than 0.005) urinary zinc excretion compared with -Zn/S with similar plasma zinc concentrations. Urinary zinc excretion correlated with urinary flow (r = 0.739, P less than 0.005), urinary protein (r = 0.635, P less than 0.01) and urinary calcium excretion (r = 0.855, P less than 0.005) in -Zn groups. -Zn/N rats had a significantly larger fecal zinc excretion for the first week post-nephrectomy, compared to -Zn/N controls (P less than 0.005). This resulted in negative zinc balance in -Zn/N animals, compared to their pre-nephrectomy balance (P less than 0.05) or to -Zn/S controls for the first (P less than 0.005) and second (P less than 0.05) weeks. -Zn/N rats had lower (P less than 0.02) hepatic zinc concentrations compared to the -Zn/S group.(ABSTRACT TRUNCATED AT 250 WORDS)

The nutritive value of amaranth grain (Amaranthus caudatus)

The nutritional value of three pale seeded and one dark seeded variety ofAmaranthus caudatus was studied by chemical analyses and in balance experiments with growing rats. Effects of processing: popping, toasting and flaking were also examined. The pale seeds contained about 14% protein, 10% fat, 2.5% ash, 64% starch and 8% of dietary fibre. The black seeds had a much higher content of fibre (16%). The concentration of essential amino acids were high. Lysine ranged from 5.2–6.0 g/16 g N in the grains, and the limiting amino acids were leucine followed by valine or threonine. The grains contained small amounts of tannin (0.3%) and heat-labile protease inhibitor activity, at levels typical of common cereal grains. Digestibility of protein in the pale seeds was high (87%) and quite unaffected by processing. Protein digestibility of the black seeds was lower, and the digestibility was further reduced by toasting. The biological value of the protein was similar in all products, and very high. The content of minerals varied among varieties and was also affected by processing. Phytate: zinc molar ratios were high in most products, and rats fed the amaranth samples with the lowest zinc contents were in negative zinc balance. In general, femur zinc concentrations were rather low. However, amaranth is an unconventional crop which deserves further attention.

Consecutive zinc balance trials in growing rats

Rats were fed a purified egg white-based diet containing 5 ppm Cu and 2, 14, or 57 ppm Zn. Zinc and copper balances were determined for eight consecutive weekly trial periods. The zinc-deficient group almost ceased to gain weight and was in slightly negative zinc balance. Groups of rats fed 14 and 57 ppm Zn gained weight at equal rates. These groups were in strongly positive zinc balance for four weeks; thereafter, they fed 57 ppm Zn retained about two times as much zinc as did the group fed the diet containing 14 ppm Zn. All groups were in null or slightly negative copper balance throughout the trial. These results suggest that zinc accumulation may be homeostatically controlled to a level in excess of that needed for maximum growth.

Effects of oral contraceptive agents on copper and zinc balance in young women

Young adult women were selected from a group of volunteers on the basis of present and past use of oral contraceptive agents. Subjects were either those who had never used oral contraceptives or those who had used an agent for a minimum of two menstrual cycles. All subjects were fed diets that provided 2.02 to 2.11 mg of copper and 9.15 to 9.10 mg of zinc daily in an 18-day controlled metabolic study. Both oral contraceptive users and nonusers were in negative zinc balance and zinc excretion as not different (P > 0.05) for the groups. Oral contraceptives did not alter (P > 0.05) the metabolic balance of copper; the mean copper retention values were -0.16 mg/day for the nonusers and -0.13 mg/day for the users of oral contraceptives. As anticipated from reports in the literature, the plasma copper levels were higher (P < 0.01) in the oral contraceptive group, but the levels of zinc were not different. Although blood levels of zinc and copper are usually changed with the use of oral contraceptives, the retention of the two nutrients appears not to be affected.

Zinc in Total Parenteral Nutrition. Requirements and Metabolic Effects

Abstract Each of 24 patients with gastrointestinal disease was studied for a period of 3 wk while receiving total parenteral nutrition (TPN) to which zinc had been added in amounts of either 0.0, 1.5, and 3.0 or 6.0, 12.0, and 23.0 mg/day for each of the (three) weekly periods. Abnormal zinc excretion occurred from the gastrointestinal tract in diarrheal stools and intestinal fluids lost through suction and fistulous discharge. Gastrointestinal loss of zinc depended on the volume of the contents lost and the source of these contents. The mean concentration of zinc in gastrointestinal contents was found to be 15.2 δg of zinc/g of contents for the output from patients with an intact small bowel and 3.6 δg/g of contents from high small bowel fistulae and after extensive small bowel resection. Urinary loss of zinc occurred in all patients but constituted the major source of excretion only in patients without diarrhea or small bowel drainage. Increased urinary zinc excretion was found to occur in association with a significantly elevated urinary nitrogen. Zinc balance could be achieved only by supplying this metal in excess of obligatory losses, and a positive zinc balance was associated with improved nitrogen retention. Hence, there appeared to be a link between the metabolism of protein and that of zinc. Patients with large gastrointestinal losses of zinc were found to have significantly lower insulin and higher glucose levels (and lower lactate and pyruvate levels) than patients with normal gastrointestinal loss. Furthermore, plasma insulin increased whenever a negative zinc balance was converted to a positive one, and vice versa. These findings raise the possibility that zinc deficiency impairs insulin response and the utilization of glucose and amino acids. Appropriate zinc replacement in such patients seems, therefore, to be an important component of total parenteral nutrition. An estimate for this replacement, based on a formula developed from the authors' observations, would have placed most patients in zinc balance.

The relationship of zinc to protein utilization in the preadolescent child

The effects of zinc intake on nitrogen utilization was investigated during a 20-day balance study with 23 preadolescent girls. The children were fed a diet which provided 4.17 g of nitrogen and 5.5 mg of zinc daily; the diet was supplemented with a combination of 5 mg of zinc and/or nitrogen supplied from either amino acids or nonspecific nitrogen. Complete collections of excreta were made throughout the study. Neither the supplementation of amino acids nor zinc improved the retention of nitrogen. Urinary excretion of urea nitrogen, uric acid, and creatinine were not different as a result of zinc supplementation. Subjects consuming the lower level of zinc were in negative zinc balance, but the subjects consuming 10.5 mg of zinc were in positive balance. The supplementation of this low protein diet with amino acids did not improve nitrogen retention.