Clinical manifestations of zinc deficiency

Zinc deficiency with acrodermatitis enteropathica-like eruption after pancreaticoduodenectomy

Pancreaticoduodenectomy (PD) is the standard operation for periampullary lesions. Most reports have focused on the clinical outcome, complications and tumor recurrence after PD. Few studies have focused on the nutritional sequelae that result from the extended resection of the upper gastrointestinal tract and disruption of the normal physiologic process of digestion. Zinc is absorbed mainly in the duodenum and proximal jejunum, which are removed during PD. Herein, we report two patients who experienced zinc deficiency with acrodermatitis enteropathica-like eruption, alopecia, glossitis and nail dystrophy after PD. The lesions improved dramatically after supplementation with zinc sulfate, pancreatic enzyme and diet instructions. No symptoms related to zinc deficiency were noted on follow-up after nutritional instructions had been given to the patients.

Pinealectomy and melatonin administration in rats: their effects on plasma leptin levels and relationship with zinc

The aim of this study was to examine effects of pinealectomy and melatonin administration plasma leptin levels and its relationship with zinc in rats. The study was conducted on 40 adult male Sprague-Dawley rats. They were divided into four groups each containing 10 animals. Group 1 served as control. Group 2 was pinealectomized group. Animals in Group 3 were pinealectomized and injected with melatonin (3 mg/kg/day, ip). Group 4 received melatonin alone (3 mg/kg/day, ip). At the end of the experiments, all animals were decapitated and trunk blood collected. Plasma leptin and zinc levels were determined by radioimmunoassay and Atomic Absorption Spectrophotometer methods, respectively. Although mean weights of the animals at the beginning were not significantly different among the groups, the mean weight of the pinealectomized group was found to be significantly lower than all other groups at the end of a six-month period (p < 0.01). Plasma leptin and zinc levels were the highest in melatonin-administered group (group 4; p < 0.01). The lowest plasma leptin and zinc levels were obtained in the pinealectomized group (group 2; p < 0.01). Changes in these two parameters were not statistically significant in groups 1 and 3. Our findings indicate that pinealectomy results in a decrease in leptin and zinc levels in rats, and that melatonin administration to pinealectomized rats prevents the decrease in the these parameters. In addition, long-term administration of melatonin to rats leads to an increase in both leptin and zinc concentrations.

Does ageing affect zinc homeostasis and dietary requirements?

Dietary intakes of zinc are lower in the elderly because of reduced energy requirements, and it is not clear whether ageing impacts on adaptive homeostatic mechanisms, namely absorptive efficiency and endogenous losses in the GI tract. Physiological requirements for zinc are unlikely to change significantly, but there are several attributes of ageing that may affect aspects of zinc metabolism (e.g. changes in gut structure and function, disease states, chronic inflammation, epigenetic changes in genes that express zinc-related proteins and drug regimens) that are worthy of further investigation. There is, as yet, no information on the effects of ageing on zinc transporters, and there are no sensitive and specific measures of zinc status, therefore dietary recommendations for zinc have been derived from factorial calculations using information on zinc absorption and loss, and estimates of dietary bioavailability.

Zinc status of Iranian preschool children

BACKGROUND

Zinc deficiency is one of the most prevalent micronutrient deficiencies in developing countries, including Iran. The main direct causes of zinc deficiency are insufficient zinc intake, absorption or metabolic disorder, and increase in need during acute growth periods.

OBJECTIVE

To determine the prevalence of zinc deficiency in preschool boys and girls in urban and rural populations in order to assist policy makers. Children of preschool age (i.e., 6 years old in Iran) were studied because interventions in this age group are believed to result in greater improvement in learning skills once these children enter school.

METHODS

A national cross-sectional study was carried out on 4,374 randomly selected healthy preschool children from Iranian families in 2001. Serum zinc concentration was measured by atomic absorption spectrometry. The cutoff point for zinc deficiency was set at a serum level of 10 micromol/L (65 microg/dL).

RESULTS

The prevalence of zinc deficiency was estimated at approximately 19.3%. The highest prevalence was seen in the region that includes Sistan and Baluchistan, South Khorasan, and the southeast area of Kerman and the lowest in the region of Boushehr, Hormozgan, and South Khoozestan. The prevalence of zinc deficiency was significantly higher in rural areas than in urban areas. No significant difference in prevalence was seen between boys and girls.

CONCLUSIONS

In the long run, nutritional security and increased access to and intake of foods with high levels of zinc are the most sustainable strategies to overcome zinc deficiency. Fortification of staple foods, improved quality of traditional bread, and supplementation for at-risk population groups are considered short- and mid-term interventions. Nutrition education and behavioral change may be long-term strategies.

Effects of zinc deficiency on oral and periodontal diseases in rats

BACKGROUND AND OBJECTIVE

The aim of this study was to investigate the alterations of oral and periodontal tissues in zinc-deficient rats compared with control rats.

MATERIAL AND METHODS

The study was carried out on 14 Sprague-Dawley rats, cessation of lactation on the 24th day after birth. Rats were randomly divided into two groups. Group I rats were fed with a zinc-deficient diet and group II rats were fed with a zinc-containing diet. At the end of the fourth week on experimental diets, alterations of the oral tissues in both groups were recorded. In addition, the gingival index (GI-Löe-Silness), plaque index (PI-Silness-Löe) and periodontal pocket depth scores were recorded in order to assess periodontal tissue health in the rats. Then, blood samples were taken and the serum zinc levels measured by atomic absorption spectrophotometry. At the end of the experiment, oral tissue samples were investigated by light microscopy. Finally, the results of the two groups were compared by using the Student's t-test.

RESULTS

The effects of zinc deficiency were observed at 10-16 d in rats. Although body weight, body length and tail length were retarded in zinc-deficient rats, they were advanced in rats fed with a zinc-containing diet. The mean plaque index and gingival index for group II rats were significantly lower than for group I rats (p<0.001), but there was no significant difference regarding pocket depth between the two groups of rats (p>0.05). Aphthous ulcer was often seen in the study group, where it was observed on the alveolar mucosa with a high rate of 29.9%. According to histological findings, there was no difference related to the epithelial keratinization of the hard palate between the two groups. However, hyperkeratosis was found on the dorsal surface of the tongue in zinc-deficient rats.

CONCLUSION

The findings indicated that oral health was better in group II rats (those fed with a zinc-containing diet) than in group I (zinc-deficient) rats. Hyperkeratinization was more prominent in zinc-deficient rats. We suggest that zinc deficiency is a potential risk factor for oral and periodontal diseases.

Clinical and biological consequences of transmetallation induced by contrast agents for magnetic resonance imaging: a review

Gadolinium-based contrast agents (CAs) are widely used to enhance the contrast of images in magnetic resonance imaging procedures. Two categories of gadolinium chelates exist: the macrocyclic molecules where Gd3+ is caged in the pre-organized cavity of the ligand and the linear molecules. Gadolinium chelates differ in their thermodynamic stability constants and in their kinetic stability. In general, macrocyclic chelates such as Gd-DOTA or Gd-HP-DO3A are more stable than linear molecules. Even among linear agents, differences can be found. There is increasing evidence that transmetallation can be found in vivo, in the case of certain CAs (especially linear chelates), with body cations such as zinc, calcium or iron. Furthermore, analytical interference with colorimetric determination of calcium has been clinically evidenced with two linear chelates, Gd-DTPA-BMA and Gd-DTPA-BMEA. Clinical cases of spurious hypocalcaemia have been reported with these molecules. Such interference with some colorimetric assays for calcium is clinically relevant in that it can lead to unnecessary and potentially harmful treatment for hypocalcaemia.

Does folic acid and zinc sulphate intervention affect endocrine parameters and sperm characteristics in men?

We evaluated pre- and post-intervention endocrine and semen parameters in a double-blind, placebo-controlled intervention study to investigate the underlying mechanism of increased sperm concentration after folic acid and zinc sulphate intervention. A total of 47 fertile and 40 subfertile males participated in a 26-week intervention study consisting of a daily treatment with folic acid (5 mg/day) and zinc sulphate (66 mg/day), or placebo. Pre- and post-intervention semen parameters, serum folate, zinc, follicle-stimulating hormone (FSH), testosterone and inhibin B concentrations were measured. The results indicated that intervention treatment significantly increased sperm concentration in subfertile males. Other semen and endocrine parameters were not affected by intervention treatment. At baseline, positive correlations were found between serum zinc and sperm concentration, motility and inhibin B. Serum zinc and FSH were inversely correlated. As (already) well known from previous research, inhibin B positively correlated with sperm concentration, motility and morphology, and was inversely correlated with FSH. The latter was positively correlated with testosterone. In addition, testosterone and inhibin B were inversely correlated. After intervention, the correlations with zinc disappeared. We conclude that the increase in sperm concentration after folic acid and zinc sulphate intervention is not the result of alterations in FSH, testosterone or inhibin B concentrations. Although zinc and folate have several effects on spermatogenesis, the underlying mechanisms involved are not clear.

Testosterone and zinc supplementation in castrated rats: Effects on plasma leptin levels and relation with LH, FSH and testosterone

The present study aims to examine how zinc and testosterone supplementation, in combination and separately, affect plasma LH, FSH and leptin levels in castrated rats. Eighty experimental animals used in the study were allocated to 8 groups, each containing an equal number of rats. Group 1, control group; Group 2, castration group; Group 3, testosterone group (5 mg/kg/day); Group 4, zinc-supplemented group (3 mg/kg/day); Group 5, testosterone and zinc-supplemented group; Group 6, zinc-supplemented castration group; Group 7, testosterone and castration group; and Group 8, zinc-supplemented, testosterone and castration group. Plasma zinc, leptin, LH, FSH and free and total testosterone levels were determined in the blood samples collected from the animals by decapitation. Group 2 had the highest leptin levels and together with group 6, it also showed the highest LH and FSH levels (p<0.01). The lowest leptin levels were observed in groups 3 and 7 (p<0.01). Leptin levels in groups 4 and 6 were higher than those in groups 1, 5 and 8 (p<0.01). LH levels in group 4 were lower than those in groups 2 and 6 and higher than those in all other groups (p<0.01). Free and total testosterone levels in groups 7 and 8 were lower than those in groups 3 and 5, but higher than those in all other groups (p<0.01). Plasma LH levels may be more effective than testosterone on plasma leptin and zinc may be an important mediator of the effect LH has on leptin.

Both zinc deficiency and supplementation affect plasma melatonin levels in rats

At physiological levels, zinc and various hormones affect each other reciprocally. Reduction in zinc levels in pinealectomized rats suggests the relation between zinc and melatonin. The effect of both zinc deficiency and supplementation on plasma melatonin levels in rats were investigated in this study. The study was done in Selçuk University, Experimental Medicine Research and Application Center. Twenty-four adult male Sprague Dawley rats were divided into 3 groups. Eight rats were fed with zinc-deficient diet. Zinc supplementation was administered intaperitoneally to 8 rats. The remaining 8 rats were used as controls. All rats sacrificed 3 weeks later. Plasma melatonin and zinc levels were determined. The plasma zinc levels of the zinc-supplemented group were higher than those of the other groups as expected (P<0.01). Similarly, the melatonin levels in the zinc-supplemented group were higher than those in the other groups. A significant decrease was observed in melatonin levels of the zinc-deficient group compared to the control and zinc-supplemented group (P<0.01). The results of this study suggest that zinc deficiency decreases the melatonin levels and zinc supplementation may increase the plasma melatonin levels in rats.

Suppressive effect of zinc on antibody response to cholera toxin in children given the killed, B subunit-whole cell, oral cholera vaccine

In a previous study, children aged 2-5 years old in Bangladesh were supplemented orally with a single dose of Vitamin A (200,000 IU) and a placebo for zinc (zinc equivalent to 20 mg of elemental zinc) everyday for 42 days (group A), zinc and a placebo for Vitamin A (group Z), zinc and Vitamin A (group AZ) or both placebos (group P). All children were orally immunised with two doses of the killed cholera vaccine containing whole cells and a recombinant B subunit of cholera toxin (CT). The number of children who responded with > or = 4-fold vibriocidal antibody (a proxy indicator of protection against cholera) was significantly greater among the zinc-supplemented groups than among the non-zinc-supplemented groups, while Vitamin A supplementation did not appear to have any effect. The sera from these children were assayed for antibody to CT. Antibody to CT is known to exert a synergistic protective effect against cholera in animal studies, and offer significantly higher short-term protection against cholera and significant short-term protection against enterotoxigenic Escherichia coli diarrhoea in humans on oral immunisation with the cholera vaccine. Children who received zinc had significantly reduced levels of serum antibodies to CT than children who received placebos only. Factorial analysis showed a trend for zinc showing a reduction in the number of children responding with CT-antibody, while Vitamin A did not appear to have any effect. Thus, zinc enhanced vibriocidal antibody response, but suppressed CT-antibody response, suggesting that zinc supplementation has different modulating effects on vibriocidal antibody response and CT-antibody response.

Serum levels of zinc and copper in hydatidiform mole

OBJECTIVE

The aim of this study was to identify any association between serum levels of trace elements zinc and copper and development of hydatidiform mole.

STUDY DESIGN

Blood samples of 35 patients with complete hydatidiform mole and 34 pregnant women controls were evaluated for serum levels of zinc and copper. Student's t-test was used for comparison of mean values of serum zinc and copper and for demographic variables. p< or =0.05 was considered statistically significant.

RESULTS

Levels of zinc in serum were found to be significantly higher in hydatidiform mole patients than controls (86.3 vs. 68.7 microg/l, p=0.027). Serum copper levels were significantly lower in hydatidiform mole patients than controls (123.8 vs. 147.8 microg/l, p=0.039; Table 2).

CONCLUSION

This is the first study in the English scientific literature reporting higher serum levels of zinc and lower serum levels of copper associated with complete hydatidiform mole.

Opposite effects of zinc and melatonin on thyroid hormones in rats

The present study was conducted to investigate how thyroid function in rats is affected by administration of 3 mg per kg per day of zinc and/or melatonin. The study was conducted with 40 Sprague-Dawley adult male rats equally divided into four groups: 1 (controls), 2 (zinc-only), 3 (melatonin-only) and 4 (zinc- and melatonin-supplemented). The supplementation was continued for 4 weeks after which the animals were sacrificed and plasma samples were obtained for determination of zinc, melatonin, free- and total triiodothyronine (T3), thyroxine (T4) and thyroid-stimulating hormone (TSH) levels. The free T3, T4 and TSH levels were lower in the melatonin group than in all other groups (P<0.01), while free- and total T3 levels were higher in the zinc group (P<0.01). The group that received zinc and melatonin combined had free thyroid hormone levels higher than the only melatonin group. These results show that melatonin has a thyroid function suppressing action, just the opposite to the actions of zinc. When zinc is administered along with melatonin, its thyroid function suppression is diminished.

Impairments to wound healing

Impaired wound healing is a complication faced by all physicians, regardless of their field of practice. Plastic surgeons are frequently called on to help treat patients who fail to heal properly. Therefore, plastic surgeons must be well versed in the intrinsic and extrinsic factors that can impair wound healing, such as nutrition, drugs, radiation, smoking, and hypoxia. Only by limiting detrimental factors can wound healing progress in a beneficial fashion.

Zinc and copper status in children with high family risk of premature cardiovascular disease

BACKGROUND

Zinc and copper are beneficial to health, growth and development, and also for the prevention of cardiovascular disease (CVD) with regards to improved dietary habits as a preliminary step in CVD prevention. This study was conducted among 2-18-year-old children with high family risk of premature CVD in comparison to controls.

SUBJECTS AND METHODS

One hundred randomly selected children whose parents had premature myocardial infarction were included in the study. The controls were 100 individuals randomly selected from the case group's neighbors and matched for age, sex, and socioeconomic status. A four-day food record questionnaire was used to assess zinc and copper intakes, and their serum levels were determined using Flame-Atomic Absorption Spectrophotometry. The data were analyzed by SPSS/Windows V6 software, using the Student's t and Mantel-Hanzel tests. Significance of differences was considered at P<0.05.

RESULTS

The daily zinc intake was significantly lower in the case than control group (6.89+/-2.97 vs. 8.30+/-2.45 mg, P=0.047). The mean serum zinc level was not significantly different between both groups (82.12+/-14.1 vs. 92.26+/-23.7 microg/dL, P>0.05). Zinc deficiency was more prevalent among the case in boys than their controls (58% vs. 18%, P=0.04). This difference was not significantly in girls (44% vs. 40%). The daily intake and serum level of copper were not significantly different between the case and control groups. No case of copper deficiency was found. The mean systolic blood pressure was not significantly different between the zinc-deficient and zinc-sufficient subjects. Although the mean diastolic blood pressure of the former was higher than the latter, there was no statistically significant difference. About 23.7% of all studied sample had mild-to-moderate degrees of failure to thrive, with significantly lower daily intake and serum zinc level than other subjects (5.14+/-1.06 mg, 82.09+/-12.74 microg/dL vs. 6.89+/-2.14 mg, 99.25+/-27.15 microg/dL, respectively, P<0.05).

CONCLUSION

It is recommended that emphasis be placed on the consumption of food rich in zinc by children, especially those with high family risk of premature CVD.

Study of zinc and growth hormone in sickle cell disease

About 25% of children with sickle cell disease (SCD) have statural deficit and retarded skeletal maturation and pubertal development. These disorders have been attributed to low serum concentrations of zinc. We report the study of serum zinc in 34 patients with SCD, of whom 17 had statural deficit (SCS group) and 17 without growth deficiency (SCN group). They were compared with 20 normal children (N group). GH secretion and thyroid function were investigated in the group with short stature (SCS) in order to rule out GH deficiency and hypothyroidism. The mean serum zinc concentration was 108.45+/-22.888 microg/100 ml in the N group, 87.529+/-30.069 microg/100 ml in the SCN group and 82.765+/-34.766 microg/100 ml in the SCS group. There was a statistically significant difference between the mean of the N group and the mean of the SCN group (p<0.05) but no difference was found between the two groups of patients (N>SCN=SCS). Although there is a well-established zinc deficiency in patients with SCD, the statural retardation found in the SCS group could not be attributed only to zinc deficiency. Many other severe metabolic disturbances are also involved.

Zinc and childhood infectious disease morbidity and mortality

Zinc is an essential mineral and deficiency results in abnormal immune function and higher rates of infectious diseases. Randomized controlled trials of zinc supplementation have been conducted in children in developing countries to determine effects on infectious disease morbidity and mortality. Zinc-supplemented children have been found to have lower rates of diarrhea, pneumonia and malaria in comparison with children not given zinc. Zinc used as an adjunct to fluid and dietary management of acute and persistent diarrhea has been found to reduce diarrheal duration and severity. Preliminary evidence suggests that zinc supplementation in children in poor developing country settings may also reduce infant mortality, but larger trials are needed to address this important issue. Preventive and therapeutic interventions should be implemented in developing countries where zinc deficiency is likely to be prevalent.

Optic nerve changes in zinc-deficient rats

In this study the optic nerve changes in zinc (Zn)-deficient rats are examined. Zinc is one of the essential trace elements and is known to be related to optic nerve diseases such as ethambutol neuropathy. However, the effect of Zn on the optic nerve has not been studied experimentally in animals. We used 3 week old weanling male Wistar Kyoto rats weighing 40-50 g. Rats were fed a Zn-deficient diet containing 0.007 mg of Zn per 100 g, all other nutrients and distilled and deionized water. The same water supplemented with 3 mg Zn per 100 g was given to the control group. After 4 or 7 weeks on a Zn-deficient diet, the optic nerve was examined with an electron microscope. A recovery group was fed a Zn-containing diet for 5 weeks after 7 weeks on the Zn-deficient diet. The serum Zn levels of the deficient group were significantly decreased at both 4 and 7 weeks. Most of the Zn-deficient rats showed hair loss around the eyes and on the extremities. Ultrastructural findings were as follows. The number of myelinated axons of Zn-deficient rats at 4 and 7 weeks were significantly decreased and the myelin sheaths were significantly thinner in the Zn-deficient groups and in the recovery group. Unmyelinated axons were more numerous than in the control rats. Destruction of myelin and proliferation of glial cells were found in the optic nerves of Zn-deficient rats. This study suggests that the optic nerve needs Zn for the maintenance of its cell structure and even if Zn is supplied to the Zn-deficient rats, destruction of the myelin structure may continue. Zn-deficiency induce a decrease of myelinated nerve fibers, and it is thought that optic neuropathy in patients treated with some drugs such as ethambutol may be a secondary change due to Zn-deficiency following drug administration.

Inhibition of carboxypeptidase A by D-penicillamine: mechanism and implications for drug design

Zinc metalloprotease inhibitors are usually designed to inactivate the enzyme by forming a stable ternary complex with the enzyme and active-site zinc. D-Cysteine inhibits carboxypeptidase, ZnCPD, by forming such a complex, with a K(i) of 2.3 microM. In contrast, the antiarthritis drug D-penicillamine, D-PEN, which differs from D-Cys only by the presence of two methyl groups on the beta-carbon, inhibits ZnCPD by promoting the release of the active-site zinc. We have given the name catalytic chelator to such inhibitors. Inhibition is a two-step process characterized by formation of a complex with the enzyme (K(i(initial)) = 1.2 mM) followed by release of the active-site zinc at rates up to 420-fold faster than the spontaneous release. The initial rate of substrate hydrolysis at completion of the second step also depends on D-PEN concentration, reflecting formation of a thermodynamic equilibrium governed by the stability constants of chelator and apocarboxypeptidase for zinc (K(i(final)) = 0.25 mM). The interaction of D-PEN and D-Cys with the active-site metal has been examined by replacing the active-site zinc by a chromophoric cobalt atom. Both inhibitors perturb the d-d transitions of CoCPD in the 500-600 nm region within milliseconds of mixing but only the CoCPD.D-Cys complex displays a strong S --> Co(II) charge-transfer band at 340 nm indicative of a metal-sulfur bond. While the D-Cys complex is stable, the CoCPD.D-PEN complex breaks down to apoenzyme and Co(D-PEN)(2) with a half-life of 0.5 s. D-PEN is the first drug found to inhibit a metalloprotease by increasing the dissociation rate constant of the active-site metal. The ability of D-PEN to catalyze metal removal from carboxypeptidase A and other zinc proteases suggests a possible mechanism of action in arthritis and Wilson's disease and may also underlie complications associated with its clinical use.

Determination of iron, copper, zinc, magnesium and selenium in plasma and erythrocytes in neurosurgical patients

A direct method for determination of Fe, Cu, Zn, Mg and Se in erythrocytes was developed. The aim of the present study was to establish a method for examining perioperative levels of the above mentioned elements simultaneously in erythrocytes and plasma by atomic absorption spectrophotometry in 11 patients undergoing neurosurgery for acute spinal nerve compressions because of intervertebral disk prolapses. Reference values for erythrocytes were 11.49 +/- 3.48 mmol/mmol Hb; 0.82 +/- 0.087 mmol/mmol Hb; 9.01 +/- 2.20 mmol/mmol Hb; 0.104 +/- 0.032 mmol/mmol Hb; 0.07 +/- 0.050 mmol/mmol Hb for iron, copper, zinc, magnesium, and selenium, respectively. Postoperative erythrocyte concentrations did not differ significantly compared to those obtained preoperatively and remained within the reference ranges perioperatively. For plasma the following reference values were used: 19.0 +/- 8.0 mmol/l (Fe); 20.1 +/- 8.2 mmol/l (Cu); 15.4 +/- 4.6 mmol/l (Zn); 0.9 +/- 0.15 mmol/l (Mg); 1.02 +/- 0.3 mmol/l (Se). There was a significant decrease in the concentration of copper in plasma (13.41 +/- 3.46 mmol/l, p < 0.1) and zinc (10.73 +/- 2.73 mmol/l, p < 0.1) immediately postoperative, iron (10.56 +/- 3.91 mmol/l, p < 0.1) and zinc on day 1 (11.28 +/- 1.88 mmol/l, p < 0.10), and a significant postoperative increase of copper on day 5 (18.81 +/- 3.97 mmol/l, p < 0.1), postoperatively. The mean plasma concentrations of iron, copper, zinc magnesium and selenium remained within the reference ranges during the entire period.

Changes in dietary zinc and copper affect zinc-status indicators of postmenopausal women, notably, extracellular superoxide dismutase and amyloid precursor proteins

BACKGROUND

Zinc is an essential trace element for human health and well-being; however, methods currently available for the assessment of zinc status in humans are unsatisfactory.

OBJECTIVE

The objective was to critically evaluate the use of various indicators of zinc status in humans in a controlled metabolic ward study.

DESIGN

Indicators of zinc status were measured in 25 healthy postmenopausal women aged 64.9 +/- 6.7 y. After a 10-d equilibration period, volunteers consumed a diet with either a low (1 mg/d; n = 12) or a high (3 mg/d; n = 13) copper content based on a total energy content of 8.4 MJ. They received the same amount of copper throughout the study. Both groups were fed the basal diet (3 mg Zn/d) with no zinc supplement for one 90-d period, and the diet supplemented with 50 mg Zn/d for another 90-d period.

RESULTS

Zinc supplementation significantly increased (P < 0.0001) extracellular but not erythrocyte superoxide dismutase activity. This increase was more apparent when subjects were fed the low-copper diet. Zinc supplementation in combination with the low-copper diet significantly decreased (P < 0.01) amyloid precursor protein expression in platelets. Other indicators of zinc status that were significantly elevated after zinc supplementation were as follows: plasma zinc and free thyroxine concentrations and mononuclear 5'-nucleotidase activity.

CONCLUSION

The measurement of serum extracellular superoxide dismutase activity may be useful as a marker for the functional assessment of zinc status in humans.

Long-term zinc and iron supplementation in children of short stature: effect of growth and on trace element content in tissues

We evaluated the effect of one year of supplementation with iron plus zinc (12 mg/day of Fe+++ and 12.5 mg/day of Zn++), zinc alone (12.5 mg/day of Zn++) and placebo on growth and on the iron, zinc, copper and selenium tissue contents in 30 well-selected children of short stature (16 M and 14 F; 4-11 years old). Before and after supplementation, we measured the concentrations of iron, transferrin, ferritin, zinc and copper in serum, of zinc in erythrocytes and leukocytes, and of zinc, copper and selenium in hair, as well as glutathione peroxidase activity in erythrocytes. Before supplementation, ferritin and serum, erythrocyte and hair zinc contents were significantly lower than in age-matched controls, while the other measured indices were in the normal range. Iron plus zinc supplementation caused an improvement in growth rate in all subjects, i.e., the median Z-score increased from -2.22 +/- 0.45 to -0.64 +/- 0.55; (p < 0.01). In the zinc-supplemented group, only the subjects whose ferritin levels were higher than 20 ng/L before supplementation showed a similar improvement of growth rate. Iron plus zinc supplementation could be a reasonable treatment in short, prepubertal children affected by marginal zinc and iron deficiency.

Celiac disease-associated alopecia in childhood

We report the association of celiac disease and alopecia in 3 children. In one, the alopecia developed after 4 years' nonadherence to a gluten-free diet; the other 2 patients presented with alopecia. Administration of a gluten-free diet resulted in partial regrowth of hair in the first child and complete hair growth in the others.

Zinc deficiency increases hypothalamic neuropeptide Y and neuropeptide Y mRNA levels and does not block neuropeptide Y-induced feeding in rats

Zinc deficiency reduces intake and produces an unusual approximately 3.5-d cycle of intake in rats. The mechanism underlying the anorexia and cycling has not yet been defined; current hypotheses suggest that alterations in amino acid metabolism and neurotransmitter concentrations may be a part of this anorexia. Recent reports indicate that appetite-stimulating neuropeptide Y (NPY) may be elevated during zinc deficiency. This suggests that a resistance to NPY may exist during zinc deficiency because NPY levels are high, yet appetite is low. The purpose of this study was to measure NPY peptide and mRNA concentrations during zinc deficiency in specific nuclei of the hypothalamus in which peptide and mRNA for NPY are known to be associated with appetite, and also to determine whether zinc-deficient rats are responsive to central infusions of NPY. Both NPY peptide levels in the paraventricular nucleus and NPY mRNA levels in the arcuate nucleus were higher (P < 0.05) in zinc-deficient rats than in zinc-adequate rats. When rats were administered exogenous NPY to the paraventricular nucleus, both zinc-deficient and zinc-adequate rats responded similarly by increasing food intake. These results suggest that NPY is elevated during zinc deficiency in an attempt to restore normal food intake levels, rather than being reduced and thereby contributing to the anorexia associated with zinc deficiency. During zinc deficiency, NPY receptors are able to bind NPY and initiate an orexigenic response.

Zinc status relates to hematological deficits in middle-aged women

OBJECTIVE

The objective of our study was to investigate zinc (Zn) status and the effects of Zn supplementation in relation to iron deficiency anemia in middle-aged women. It is important to define the role of Zn in hematologic abnormalities and to determine the frequency of Zn deficiency.

METHODS

Fifty-two Japanese women, selected from a health examination survey on 6200 women, had hemoglobin concentrations below 12.0 g/dl, total iron binding capacity (TIBC) below 390 micrograms/dl and fairly normocytemia. These 52 were divided into three groups and we then compared the hematological status before and after iron (group A) or Zn (group B) or iron plus Zn (group C) supplementation.

RESULTS

After treatment, concentrations of hemoglobin (Hb) increased slightly in groups A and B, but not statistically significant. In group C, Hb levels were significantly increased from 10.8 +/- 1.1 to 12.8 +/- 1.1 g/dl. Furthermore, numbers of RBC and reticulocytes, and concentrations of albumin were also increased significantly. Increased values over 1.0 g/dl of hemoglobin levels were noted in four women (26.6%) in group A, three women (14.2%) in group B and 13 women (81.2%) in group C.

CONCLUSION

Zn status to some extent can account for hematological abnormalities in middle-aged women. At least 5.0% of middle-aged Japanese women may have Zn deficiency. Normocytic anemia with low TIBC levels may serve as a good indicator of a marginal Zn deficiency.

Calcium, magnesium, and zinc status in experimental hypothyroidism

In this study, experimental hypothyroidism was established and used to investigate possible alterations in the calcium, magnesium, and zinc homeostasis by assessing their concentration in plasma and erythrocytes. Hypothyroidism was induced by administration of methimazole an iodine blocker at a dose of 75 mg/100 g food for 3 wk. In the methimazole-induced hypothyroid state, the experimental animals showed a significant decrease in plasma zinc concentration, whereas a significant increase in plasma magnesium concentration occurred. No change was observed in plasma calcium concentration. The erythrocyte zinc and calcium concentrations were found to be increased, whereas magnesium concentration decreased. Erythrocyte magnesium concentration showed a significant positive correlation with T4 values. The study provides evidence for marked alterations in homeostatis of zinc, magnesium, and calcium.

Zinc and copper levels in serum and urine: relationship to biological, habitual and environmental factors

Zinc and copper levels were determined in serum and urine of 434 subjects living in an industrial and an agricultural area of Tarragona Province, Spain. Zinc and copper concentrations were related to a range of factors such as sex, age, blood pressure, and drinking and smoking habits. Geometric mean serum zinc and copper concentrations were, respectively, 113.9 and 84 micrograms dl-1, while the mean values for urine zinc and copper concentrations were 698.7 and 26.6 micrograms g-1 creatinine. Serum zinc and copper levels and urine copper concentrations in men were significantly lower than in women, while there were no differences in serum or urinary zinc and copper levels with age. The consumption of alcohol significantly reduced the levels of zinc and copper in serum, whereas blood pressure had no influence on these values. The levels of zinc and copper in urine were not affected by the smoking and drinking habits, place of residence, or blood pressure. In general terms, the results of this study agree with previously reported values from different countries.

Zinc supplementation alters thyroid hormone metabolism in disabled patients with zinc deficiency

OBJECTIVE

We examined zinc (Zn) status in relation to thyroid function in disabled persons, because the association between Zn deficiency and thyroid function remains controversial.

METHODS

After measuring serum free 3,5,3'-triiodothyronine (T3) and free thyroxine (T4) in 134 persons, TSH-releasing hormone (TRH) injection test and estimation of Zn status were conducted in persons with low free T3.

RESULTS

Thirteen had low levels of serum free T3 and normal T4. Patients with elevated levels of serum 3,3',5'-triiodothyronine (rT3) showed an enhanced reaction of serum thyrotropin (TSH) after TRH injection. Nine of 13 patients had mild to moderate Zn deficiency evaluated by body Zn clearance and increased urinary Zn excretion. After oral supplementation of Zn sulphate (4-10 mg/kg body weight) for 12 months, levels of serum free T3 and T3 normalized, serum rT3 decreased, and the TRH-induced TSH reaction normalized. Serum selenium concentration (Type 1 T4 deionidase contains selenium in the rat) was unchanged by Zn supplementation.

CONCLUSION

Zn may play a role in thyroid hormone metabolism in low T3 patients and may in part contribute to conversion of T4 to T3 in humans.

Mild to moderate zinc deficiency in short children: effect of zinc supplementation on linear growth velocity

Twenty-one prepubertal, short Japanese children (11 boys) without endocrine abnormalities were identified as having mild-to-moderate zinc deficiency by zinc kinetics studies (zinc body clearance > or = 20 ml/kg per hour). Only one child had a serum zinc level < 65 micrograms/dl (cutoff level). A total of 10 children (5 boys) received 5 mg/kg per day of zinc sulfate for 6 months; 11 untreated children (6 boys) served as control subjects. During treatment, calorie intake (p < 0.01), growth velocity (p < 0.01), serum zinc, calcium, and phosphorus concentrations, alkaline phosphatase activity (p < 0.001), percentage of tubular reabsorption of phosphorus (p < 0.05), ratio of maximal tubular reabsorption rate for phosphorus to the glomerular filtration rate (p < 0.05), serum osteocalcin level (p < 0.01), and plasma insulin-like growth factor 1 (p < 0.05) were significantly increased, but urinary excretion of growth hormone was unchanged in the zinc-supplemented group. All these values were unchanged in the untreated children. We conclude that zinc supplementation is effective for inducing growth in short children with zinc deficiency, and that body zinc clearance tests facilitate detection of marginal zinc deficiency.

Zinc kinetics in patients with bone demineralization due to physical immobilization

To examine the relationship between zinc (Zn) status and bone demineralization, a body Zn kinetics study was performed with 74 (37 male, 37 female) disabled persons ranging in age from 16 to 45 years. Three groups were classified according to degree of limited mobility: group 1 (n = 23), capable of walking; group 2 (n = 20), capable of crawling; group 3 (n = 31), bed-ridden, Serum Zn levels were similar in the three groups, whereas body Zn clearance and the distribution of Zn showed a pattern [group 1 < group 2 < group 3 (p < 0.01, p < 0.05)], with the reverse in cases of bone mineral density (BMD) [group 1 > group 2 > group 3 (p < 0.01)]. Renal handling of Zn did not different among the three groups. There was a negative correlation between Zn distribution volume and values of BMD (p < 0.005, gamma = 0.387). Thus, various organs, as well as the skeleton, are Zn deficient in immobilized patients.

Erythrocytes, erythrocyte membranes, neutrophils and platelets as biopsy materials for the assessment of zinc status in humans

During a controlled zinc depletion-repletion study, fifteen men aged 25.3 (SD 3.3) years were fed on a low-Zn diet with high phytate:Zn and phytate x calcium:Zn molar ratios for 7 weeks, followed by a 2 week repletion period when 30 mg supplemental Zn/d was given. Changes in plasma, urine, and hair Zn concentrations, taste acuity, and cellular immune response confirmed the development of mild Zn deficiency. Zn concentrations in neutrophils, platelets, erythrocytes and erythrocyte membranes, mean platelet volume, and activities of alkaline phosphatase (EC 3.1.3.1) and alpha-D-mannosidase (EC 3.2.1.24) in neutrophils did not respond to changes in Zn status. In contrast, alkaline phosphatase activity in erythrocyte membranes showed a significant decline which was consistent in all subjects (nmol product formed/min per mg protein; baseline v. 7-week Zn depletion, 0.656 (SD 0.279) v. 0.506 (SD 0.230), at 7 weeks; P < 0.05); neutral phosphatase activity remained unchanged. Alkaline phosphatase activity in erythrocyte membranes may be a potential index of Zn status in humans.

Intestinal nematode infections in children: the pathophysiological price paid

The mechanism by which small animals such as rodents resist or eliminate nematode parasites requires mucosal inflammation as the final effector of the immune response. The resulting freedom from chronic infection may be worth the price of short-term illness. Putative vaccines which attempt to enhance the natural effect will have to take into account the inflammatory cost to the host. Human helminthiases involve a more stable equilibrium between host and parasite. The medical literature on hookworm disease and clinical ascariasis describes, for the former, some chronic inflammatory effects correlated with worm burden, but for the latter a less quantified or predictable set of detrimental effects. We describe a current, systematic study of the inflammatory response to whipworm infection, in which anaemia, growth retardation and intestinal leakiness are viewed as predictable consequences related to infection intensity. There is evidence for the absence of cell-mediated immunopathology. However, a specific, IgE-mediated local anaphylaxis may, at least partly, mediate the deleterious effects. Increased numbers of mucosal macrophages may also contribute to the chronic, systemic effects through their output of cytokines. Similar attempts to show the mechanisms of pathogenesis and quantify the effects of hookworm disease should be undertaken.

Zinc uptake by primate retinal pigment epithelium and choroid

We studied zinc uptake by nonhuman primate retinal pigment epithelium (RPE) and choroid, using 65Zn as a probe. With intravenously administered 65ZnCl2, virtually all detectable tracer was lost from the plasma after 20 hours but the pigment epithelium-choroid showed prominent uptake and retention. Plasma concentrations of oral 65ZnO remained high 20 hours after feeding. Uptake and retention of orally administered 65Zn as 65ZnO from the bloodstream by the RPE/choroid was avid in both young and old animals. Excretion in urine and feces was minimal. All pigmented ocular tissues took up and retained 65Zn. A survey of total zinc content of human and nonhuman primate ocular tissues showed that the pigmented tissues had consistently higher concentrations of zinc. Our results demonstrate for the first time direct uptake and retention of zinc from the blood by primate RPE and other ocular tissues.

Absorption and metabolism of oral zinc gluconate in humans in fasting state, during, and after a meal

The absorption and metabolism of zinc in a commercial form for oral use (Rubozinc, 15 mg zinc as gluconate) were investigated in 10 subjects by a kinetic study of the serum zinc profile after administration of 45 mg zinc under three conditions: after an overnight fast, during a standardized breakfast, and 2 h after this meal. The pharmacokinetic parameters were calculated by a method suitable to the characterization of rebound effects (recycling of the element in the gastrointestinal tract). In fasting state, the parameters were comparable to those previously collected in the same subjects with oral 45 mg zinc as sulfate, except with very significantly higher Cmax and area under curve (AUC), showing a better bioavailability for zinc in the commercial form. The light meal perturbed the absorption process as evidenced by the significant increases in the lag time (+180%), the tmax (+57%), and the lag times for the first two cycles during the meal. However, the parameters returned to normal values 2 h after the meal. The Cmax only moderately decreased during the meal (31%) as did the AUC (-28%). An important delay in the absorption of zinc in the commercial form when taken during a meal was therefore demonstrated, but the effect on zinc bioavailability was only moderate.

Neonatal skin disorders

Skin disorders are commonly seen in the neonatal period. A recent survey of neonates demonstrated that almost every neonate had some skin lesion. The most common skin findings are desquamation, Epstein's pearls, sebaceous hyperplasia, milia, toxic erythema, salmon patch, hypertrichosis, and Mongolian spot. In addition to these common cutaneous findings, other disorders may exist and are discussed in this article.

[Effect of zinc substitution on lymphocyte subsets and cellular immune function in hemodialysis patients]

Infection is a major cause of morbidity and mortality in patients undergoing hemodialysis for end stage renal disease. Low plasma zinc levels have been associated with immunodepression in these patients. In a randomized, placebo controlled double-blind cross over study, plasma zinc levels, delayed hypersensivity to 7 Antigens (Merieux-Multitest), absolute lymphocyte counts, T- and B-lymphocytes, suppressor-T and helper T-cells and natural killer cells were studied in 25 hemodialysis patients before, during and after intravenous zinc supplementation for 8 weeks. The hemodialysis patients had significantly lower predialysis plasma zinc concentrations compared to 76 healthy controls (74 +/- 12 vs. 126 +/- 28 mcg/dl, p less than 0.001). The plasma zinc concentrations increased to the normal range during the treatment period. Lymphocyte subtype analysis showed a significant decrease of suppressor-T cells and an increase of the helper-T/suppressor-T ratio (2.09 +/- 0.26 vs. 3.18 +/- 0.48, p less than 0.05) after zinc supplementation. Delayed hypersensivity to intradermal antigens increased significantly only after zinc treatment (2.0 +/- 0.7 vs. 5.8 +/- 1.7, p less than 0.05), not after placebo. The changes were reversible after finishing the zinc treatment. It is concluded, that plasma zinc levels are reduced in hemodialysis patients and that the substitution of zinc restores some of the depressed immune functions in these patients.

Trace minerals in the nutrition of children

Trace elements perform important functions in growth and development. However, little information exists about their dietary requirements during the demanding period of infancy. Opportunities to add to knowledge of the physiologic significance and dietary adequacy of trace elements in human nutrition are provided by recent analytic advances. Specific, sensitive, and reliable methods for the detection of trace element imbalances are sorely needed. Although several factors influence the dietary needs of these essential elements, the basis for establishing dietary needs in infants is hindered by the death of studies that have assessed their bioavailability in this age group. Thus until it has been conclusively shown otherwise, the physiologic response to human milk is used as the standard for infant feeding practices. This review is limited primarily to the physiologic significance and bioavailability of zinc, copper, manganese, molybdenum, chromium, fluoride, and selenium. The space devoted to each trace element is not meant to represent the element's importance but, rather, to reflect some of the present understanding of its metabolism and utilization.

Acrodermatitis enteropathica in Saudi Arabia

Four patients with acrodermatitis enteropathica (AE) are presented from three Saudi families. The clinical picture in these patients is basically similar to that described elsewhere. These patients, however, showed different degrees of involvement of various body systems. In all cases, low serum zinc levels were documented, and they responded well to zinc supplementation. In the follow-up evaluation, angular cheilitis was observed as a feature that appears to herald the relapse of disease. Interestingly, when patients are treated, it was the last sign to disappear. Current information on zinc is summarized.

Nutritional deficiency and the skin

Cutaneous changes occur in deficiency states of many nutritional elements: ascorbic acid, retinol, protein-energy, cyanocobalamin, phytonadione (vitamin K), biotin, ribroflavin, pyridoxine, niacin, essential fatty acids, and zinc. There are also inherited disorders of copper, biotin, zinc, and tryptophan metabolism. Cutaneous vitamin D synthesis is inhibited by sunscreen use. The striking skin changes of the glucagonoma syndrome may be related to nutritional pathways.

Lymphocyte alterations in zinc-deficient calves with lethal trait A46

Lymphocyte numbers and activities were evaluated at 2, 4, 8 and 12 weeks of age in two calves with lethal trait A46 (A46), a genetic disorder affecting intestinal zinc absorption. Plasma zinc concentrations declined to subnormal by 3 weeks of age, after which anorexia, diarrhea, alopecia and hyperkeratosis occurred. Lymphocyte response to phytohemagglutinin-P (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM) stimulation was variably reduced. CD4+ T-lymphocytes were subnormal on at least one observation period following onset of zinc deficiency, and relative numbers of B lymphocytes were decreased at 8 weeks. Secondary antibody responses to bacteriophage phi X 174 were significantly reduced. The results demonstrate that calves homozygous for the A46 trait have normal numbers of functional lymphocyte subpopulations at birth, and that the activity of their lymphocytes is altered once the calves become zinc deficient.

Alterations in magnesium and zinc metabolism in thyroid disease

Magnesium (Mg) and zinc (Zn) status was assessed in subjects to evaluate the effects of thyroid diseases on Mg and Zn metabolism. Plasma and red blood cell (RBC) concentration and peripheral blood mononuclear cell (MNC) content of Mg and Zn, and 24-hour urinary excretion of Mg, Zn, creatinine (Cr), calcium (Ca), sodium (Na), and potassium (K) were measured in 11 thyrotoxic, 29 hypothyroid, and 25 euthyroid control subjects. Serum albumin, alpha 2-macroglobulin, and the binding of Zn to albumin were also determined. Plasma and RBC Mg concentrations were low in half of the hyperthyroid subjects, but mean values were not significantly different from controls. Urinary excretion and clearance of Mg were lower in hypothyroid subjects, but differences were removed when expressed relative to Cr excretion and clearance. Similar patterns were noted for urinary Ca, Na, and K, suggesting that their reduced excretion reflects alterations in renal hemodynamics. Plasma Zn was lower in hypothyroid subjects and correlated with serum albumin; MNC Zn and urinary Zn were also low. Plasma Zn concentration was normal and serum albumin significantly lower in the hyperthyroid group than in the control group. Further, RBC Zn content was significantly lower in hyperthyroid subjects, and inversely related to plasma thyroxine concentration. The hyperthyroid group also excreted significantly greater amounts of Zn than controls, indicative of a catabolic process. This increased urinary loss may reflect a shift in the distribution of plasma Zn between ultrafilterable and Zn-albumin complexes. In summary, this study provides evidence for marked alterations in Zn homeostasis in persons with thyroid disease. Whether the observations indicate deficiency states and have clinical implications will require further investigation.