Is zinc deficiency a risk factor for atherosclerosis?

The development of atherosclerosis is influenced by genetic, lifestyle and nutritional risk factors. Zn and metallothionein deficiency can enhance oxidative-stress-related signalling processes in endothelial cells, and since changes in available plasma Zn may affect the Zn status of the endothelium, Zn deficiency could be a risk factor for IHD. Although the association of Zn with many proteins is essential for their function, three key signalling processes are highlighted as being principal targets for the effect of Zn deficiency: the activation of NF-kappaB, the activation of caspase enzymes and the signalling of NO. The need to develop a reliable indicator of Zn status is critical to any epidemiological approach for studying the relationship between Zn status and disease incidence. Studies using appropriate animal models and investigating how the plasma Zn pool influences endothelial intracellular labile Zn would be helpful in appreciating the importance of Zn deficiency in atherogenesis.     

Does zinc produce reactive oxygen species in Ruditapes decussatus?

Zinc is an essential trace element with many enzymatic functions that include antioxidant properties. To investigate whether an excess of Zn in the cells produces cytotoxicity or tissue damage or an imbalance in the antioxidant systems, marine clams (Ruditapes decussatus) were exposed to two sublethal Zn concentrations (100 and 1000 microg L(-1)) for 28 days. The effects of Zn on the activities of protective antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase, both total and selenium-dependent), lipid peroxidation, and metallothionein induction were followed in the gills and digestive gland of these clams. The results indicate that the effect of Zn exposure in this clam species depends not only on the tissue but also on the Zn concentration present. In the gills, catalase activity was enhanced by Zn exposure, whereas total glutathione peroxidase activity was inhibited. Lipid peroxidation occurred only in the clams exposed to the highest Zn concentration. In the digestive gland, the impact of Zn exposure on metabolic activity was less evident than in the gills. The most evident effect in both tissues was the enhancement of catalase activity by Zn exposure. Catalase and total glutathione peroxidase activities as well as lipid peroxidation are promising biomarkers to assess the effects of Zn in the gills of R. decussatus.     

Is there a potential therapeutic value of copper and zinc for osteoporosis?

Osteoporosis is almost universal in very old age, and is a major cause of morbidity and mortality in the elderly of both sexes. Bone is lost at a rate of 0.2-0.5 %/year in both men and women after the age of 40-45 years. The causes of age-related changes in bone mass are multifactorial and include genetic predisposition, nutritional factors, endocrine changes, habitual exercise levels and body weight. Bone loss is accelerated to 2-5 % year immediately before and for up to 10 years post-menopause (Heaney, 1986). In women hormone-replacement therapy is effective in reducing the rate of bone loss caused by this peri-menopausal decrease in hormone levels (Smith & Studd, 1993); however, in men and older women (>10 years post-menopause) nutrition plays a key role in the rate of bone loss. One factor contributing to bone loss in the elderly may be a subclinical Zn and/or Cu deficiency, due to a reduced dietary intake of micronutrients and reduced absorption (Thomson & Keelan, 1986). Zn and Cu are essential cofactors for enzymes involved in the synthesis of various bone matrix constituents. Paradoxically, Ca supplementation may accentuate the problem of reduced Zn and Cu levels by impairing the absorption of simultaneously-ingested Zn and the retention of Cu (Snedeker et al. 1982; Grekas et al. 1988). The present paper will review the current literature on the potential benefits of Cu and Zn supplementation in reducing bone loss, and present new information on the effect of Ca supplementation on Zn and Cu status in post-menopausal women with osteoporosis.     

Could zinc prevent reproductive alterations caused by cigarette smoke in male rats?

The aim of the present study was to evaluate the effects of zinc on fertility through semen parameters, testosterone level and oxidative DNA damage to spermatozoa of rats exposed to cigarette smoke. Male Wistar rats (60 days old) were divided into four groups (n = 10 per group): control, cigarette-smoking (20 cigarettes per day), zinc (zinc chloride 20 mg kg?1 day?1) and zinc plus cigarette-smoking (zinc chloride 20 mg kg?1 day?1; 20 cigarettes per day). The treatment was applied for nine weeks and the following parameters were analysed: bodyweight, wet weights of the reproductive organs and the adrenal gland, plasma testosterone concentration, testicular function (seminal analysis and daily sperm production) and sperm DNA oxidative damage. The exposure to cigarette smoke decreased testosterone concentration, the percentage of normal morphology and the motility of spermatozoa. In addition, this exposure increased sperm DNA oxidative damage. Zinc treatment protected against the toxic damage that smoking caused to spermatozoa. This study showed a correlation between smoking and possible male infertility and subfertility, and also that the majority of smoking-induced changes in spermatozoa were prevented by zinc treatment. In conclusion, zinc, an antioxidant and stimulant of cell division, can be indicated as a promising treatment in men with infertility caused by the toxic components of cigarette smoke.     

Probiotics and zinc in acute infectious gastroenteritis in children: are they effective?

OBJECTIVE: Several studies in recent decades have assessed the effects of different probiotics in acute gastroenteritis, showing that specific strains of Lactobacilli (mainly Lactobacillus casei GG) and Saccharomyces boulardii may exert some beneficial therapeutic actions, mainly when used in rotavirus gastroenteritis, at a high dose, and in the early phase. The mechanisms of action of probiotics are not completely elucidated but seem to involve a complex interaction among epithelial, molecular, metabolic, and immune responses. Data on the prevention of community-acquired, nosocomial, and travelers' diarrhea are currently conflicting. Because each micro-organism has different properties, an accurate selection of the strain, dose, and patient should be cautiously considered. METHODS AND RESULTS: Several reports from developing countries have demonstrated that supplements of zinc also provide significant reduction in stool output and duration, persistency, and severity of diarrhea. In view of the published data and of the different actions of zinc (such as improvement of the immune status, intestinal permeability, epithelial and enzymatic function, and electrolyte transport), the use of zinc as adjunctive therapy to oral rehydration solution has the potential to improve the management of diarrhea and decrease complications in children worldwide. In contrast to probiotics, which most trials in the developed world have used, there has been no trial with zinc performed in developed countries. CONCLUSION: Data on the effect of a combined administration of zinc and probiotics in acute gastroenteritis are urgently needed.     

High zinc content of scalp hair in rural West Java: A rice‐eating community

Zinc concentrations in scalp hair were determined in 50 Sundanese villagers in West Java, Indonesia. Hair zinc levels increased with age until about 20 years of age and then became constant. The mean level and S.D. of the zinc concentration in adults aged 20 years or more was 199.8 ± 26.7 μg/g (n = 36), which was higher than the reported values in several countries. Our previous study revealed that the dietary zinc intake amounted to 24.9 mg/day for adults and the high consumption of rice, their staple food, contributed 60% of the total daily zinc intake. Although there are some problems in the Sundanese diet such as a shortage of animal products, a diet depending much on rice seems to have an advantage as concerns the nutritional status of zinc.     

Does zinc deficiency play a role in stunting among primary school children in NE Thailand?

Stunting in school-age years may result in a decrease in adult size, and thus reduced work capacity and adverse reproductive outcomes. We have compared the mean intakes of energy, protein and selected growth-limiting nutrients in fifty-eight stunted children and 172 non-stunted controls drawn from 567 children aged 6-13 years attending ten rural schools in NE Thailand. Control children were selected randomly after stratifying children by age in each school. Dietary data were calculated from 24-h recalls using nutrient values from Thai food composition data and chemical analysis. Inter-relationships between stunting and sociodemographic, anthropometric and biochemical variables were also examined. Biochemical variables investigated were serum albumin, zinc, ferritin, transferrin receptor and retinol, and iodine in casual urine samples. Significantly more males than females were stunted (males, n 38, 65.5% v. females, n 20. 34.5%: P=0.025). Stunted males had lower mean intakes of energy, protein, calcium, phosphorus and zinc, and a lower mean (95% CI) serum zinc (9.19 (8.53, 9.84) v. 9.70 (8.53, 9.29) micromol/1) than non-stunted males; no other biochemical differences were noted. Stunted males also had a lower mean arm muscle area (P= 0.015), after adjusting for age, than non-stunted males. In conclusion, the lower dietary intakes of the stunted males compared to their non-stunted counterparts may be associated with anorexia and hypogeusia induced by zinc deficiency. Hence, zinc deficiency may be a factor limiting linear growth, especially among boys in NE Thailand, but more research is needed to establish whether other factors also play a role.     

Intractable diarrhea in infancy--whether infection, zinc deficiency, cholestasis and hemorrhage are causes or results?

Although there has been a marked decrease in the number of infants with intractable diarrhea in Japan, the difficulty in treating it still remains unchanged. Here we report two infants who suffered presumably from "chronic nonspecific enterocolitis" with resistance to the usual treatment. Besides prolonged diarrhea and weight loss, they showed manifestations such as infection, zinc deficiency, cholestasis, abnormal blood coagulation, etc. In this paper, we discuss whether they are causes, effects, results, or coincidences. In spite of the reduction of diarrhea after 3 months of age, both babies are even now being followed up by us because of their still poor weight gain.     

assessment of zinc nutrition using plasma angiotensin-converting enzyme activity (ace)in patients receiveng parenteral nutrition

Despite our recognition for biological role and es-sentiality of zinc (Zn)in human nutrtion,clinical as-sessment of Zn status remains highly problematic.Recent animal studies showed the change in plasmaACE (one of the Zn-enzymes) with addition of Zn invitro was greater corresponding to the feeding periodof Zn deficient diet.In this study,we examinedwhether ACE ratio (increase with Zn/basal Ace)could be a sensitive parameter of Zn nutrition in hu-mans as well.ACE ratio was determined by the in-crement of ACE when added 450μmol/L of ZnSO4.4H_2O to equivalent amount of plasma.which mightbe the optimal concentration in our preliminary study.In adult patients with intestinal failure receiving homeparenteral nutrition(HPN;100～220μmol/day of Znwas administered) (short bowel syndrome;3,     

GLV supplements increased plasma β–carotene, vitamin C, zinc and hemoglobin in young healthy adults

Summary Background Green leafy vegetables (GLV) are rich sources of β–carotene, iron and other micronutrients. Our in vitro studies have demonstrated good antioxidant potential in GLV. Moreover linkages of GLV intakes with plasma retinol and ascorbic acid were seen in apparently healthy Indians. Aim of the study To investigate the effect of GLV as a natural fortificant of multiple micronutrients through a prospective human trial. Methods Short–term (0–4 h) response (AUC) of single dose of 7.9 mg β–carotene and 130 mg ascorbic acid through a spinach–carrot meal against the standard meal without GLV plus10 mg β–carotene and 150 mg ascorbic acid tablets was studied in two groups of 4 young volunteers each. In the second trial of 3 weeks' supplementation, 5 groups of young adults (n = 40) were given either 100 g GLV/day alone or with tablets of vitamin E (100 mg/day), or C (100 mg/day) or more oil (5 g/day) or non–GLV meal with tablet of β–carotene (10 mg/day). Hemoglobin (Hb), plasma β–carotene, zinc, vitamin C, glucose, and triglycerides were measured. Results In a postprandial response, AUC were comparable in both GLV and standard meals for β–carotene and ascorbic acid. In case of triglycerides and glucose AUC the GLV meal showed a better recovery to the baseline value after 4 hours than the standard meal. Three weeks' supplementation of GLV with more oil resulted in significant increase of plasma β–carotene (51%) and Hb (9%). GLV with vitamin E showed a significant increase in plasma β–carotene (40%), Hb (8%) and plasma vitamin C (6%). Supplementing β–carotene without GLV significantly increased Hb (11%), plasma zinc (14%) in addition to β–carotene. Multiple regression analyses weighted for energy intake indicated a significant association of percent increase in Hb with intakes of iron, riboflavin, folic acid, β–carotene, copper, phytate and fiber (p < 0.01), percent change in plasma zinc with intakes of zinc, β–carotene, vitamin C, riboflavin, copper, iron, and thiamin (p < 0.01), percent change in vitamin C with intakes of vitamin C, vitamin E, niacin, riboflavin, thiamin, β–carotene, zinc, phytate and fiber (p < 0.05) and percent change in plasma β–carotene with intakes of β–carotene, thiamin, folic acid, zinc, phytate and tannins (p < 0.05). Conclusion Using 100 g GLV/day with 10 g oil could be a single moderate strategy for supplementation of iron, β–carotene, ascorbic acid and zinc.     

Effect of beringite on cadmium and zinc uptake by plants and earthworms: more than a liming effect?

Metal-contaminated soils are potentially harmful to plants, animals, and humans. Harmful effects are often related to the free-metal concentration in the soil solution. Immobilization is a potentially useful method to improve the quality of metal-contaminated soils by transforming free-metal ions into species that are less mobile and less toxic. The effect of many immobilizing products can be attributed to sorption on the surface of the material. Alkaline materials also enhance adsorption to soil particles by decreasing proton competition. Immobilization should preferably be evaluated independently of soil pH to discriminate between these processes. In this study, the immobilizing effect of beringite, an alkaline alumino silicate, was compared with that of lime. Plants (Swiss chard [Beta vulgaris L. var. cicla]) were grown on a soil contaminated with cadmium and zinc and treated with graded amounts of beringite or lime. Metal availability, as determined by a 0.01 M CaCl2 extraction, and metal uptake by plants strongly decreased in all treated soils. Beringite did not reduce metal availability more than liming when the obtained pH levels were similar. The effect of beringite can, therefore, be explained as a liming effect, at least for the duration of our experiment (10 weeks). The effect of beringite and lime on metal accumulation by earthworms (Eisenia veneta and Lumbricus rubellus) was small or not significant, although the CaCl2-extractable metal concentration in treated soils decreased by more than 90%. We conclude that immobilizing agents based on a liming effect can decrease metal uptake by plants, but they will hardly affect metal uptake by earthworms. Hence, these materials can reduce negative ecological effects of metal contamination on plants and herbivores, but not on earthworm predators.     

Are changes in food consumption patterns associated with lower biochemical zinc status among women from Dunedin, New Zealand?

Reductions in red meat and increases in cereals in the diet may compromise the intake and bioavailability of Zn. In this cross-sectional study of 330 premenopausal New Zealand women aged 18--40 years, we have assessed the inter-relationships among dietary intakes (via computer-administered food-frequency questionnaire), biochemical Zn status, and anthropometric indices, and compared our results with earlier data. Fasting serum (12.00 (sd 1.36) micromol/l) and hair Zn (2.71 (sd 0.36) micromol/g) were lower than those for young Dunedin, New Zealand, women in 1973 (non-fasting serum Zn 18.6 (sd 4.6) micromol/l, hair Zn 2.99 (sd 0.35) micromol/g). Further, our mean serum Zn was at the 25th percentile of the US National Health and Nutrition Examination Survey (NHANES) (1976--1980) reference sample for women aged 20--44 years. Meat-poultry-fish contributed only 28 % total Zn in the present study, a level comparable with that from cereals-nuts-legumes (27 %), compared to about 40 % in 1989. Significant negative correlations existed between serum Zn and dietary [phytate]:[Zn] molar ratios (r -0.163, 35 % had diets with [phytate]:[Zn] >15, a level said to compromise Zn status. Mean serum Zn of a subgroup of non-oral contraceptive users free of infection was higher in the red-meat eaters (n 149) compared with non-red-meat eaters (n 48) (12.2 v. 11.8 micromol/g, In contrast, serum Zn was lower in those with dietary [phytate]:[Zn] ratios >15 v. <15 (i.e. 11.9 v. 12.3 micromol/l, We postulate that the lower biochemical Zn status of these New Zealand women may be associated in part with changes in food selection patterns, which have led to a reduction in the bioavailability of dietary Zn.