Zinc

Zinc: An Essential Trace Element for Parenteral Nutrition

Development of a Plasma Zinc Concentration Cutoff to Identify Individuals with Severe Zinc Deficiency Based on Results from Adults Undergoing Experimental Severe Dietary Zinc Restriction and Individuals with Acrodermatitis Enteropathica

Assessment of Zinc Status

Zinc Deficiency Is Common among Healthy Women of Reproductive Age in Bhaktapur, Nepal

Reference Cut-Offs to Define Low Serum Zinc Concentrations in 1-19 Year Old Indian Children and Adolescents

The assessment of dietary zinc intakes is an important component of evaluating the risk of zinc deficiency in populations, and for designing appropriate food-based interventions, including fortification, to improve zinc intakes. The prevalence of inadequate zinc intakes can describe the relative magnitude of the risk of zinc deficiency in the population and identify subpopulations at elevated risk. As a cornerstone to evaluating the adequacy of population zinc intakes globally, a set of internationally appropriate dietary reference intakes must be defined. The World Health Organization/Food and Agriculture Organization/International Atomic Energy Agency (WHO/FAO/IAEA) and the Food and Nutrition Board/US Institute of Medicine (FNB/IOM) have presented estimated average requirements (EAR) for dietary zinc intake, and, more recently, the International Zinc Nutrition Consultative Group (IZiNCG) presented a revised set of recommendations for international use. A prevalence of inadequate zinc intakes greater than 25% is considered to represent an elevated risk of population zinc deficiency. As the requirement estimates are derived from smaller, clinical studies and, for children, most components of the estimates are extrapolated from data for adults, it was desirable to evaluate their internal validity. The estimated physiological requirements for adult men and women appear to adequately predict zinc status as determined by biochemical indicators of status and/or zinc balance. With the use of data from available studies, the reported prevalence of low serum zinc concentration and the estimated prevalence of inadequate zinc intakes predict similar levels of risk of zinc deficiency, particularly among pregnant and nonpregnant women. Conformity between these two indicators is less consistent for children, suggesting that further data and/or direct studies of zinc requirements among children are needed.

BackgroundAdequate zinc nutrition is essential for adequate growth, immunocompetence and neurobehavioral development, but limited information on population zinc status hinders the expansion of interventions to control zinc deficiency. The present analyses were conducted to: (1) estimate the country-specific prevalence of inadequate zinc intake; and (2) investigate relationships between country-specific estimated prevalence of dietary zinc inadequacy and dietary patterns and stunting prevalence.Methodology and Principal FindingsNational food balance sheet data were obtained from the Food and Agriculture Organization of the United Nations. Country-specific estimated prevalence of inadequate zinc intake were calculated based on the estimated absorbable zinc content of the national food supply, International Zinc Nutrition Consultative Group estimated physiological requirements for absorbed zinc, and demographic data obtained from United Nations estimates. Stunting data were obtained from a recent systematic analysis based on World Health Organization growth standards. An estimated 17.3% of the world’s population is at risk of inadequate zinc intake. Country-specific estimated prevalence of inadequate zinc intake was negatively correlated with the total energy and zinc contents of the national food supply and the percent of zinc obtained from animal source foods, and positively correlated with the phytate: zinc molar ratio of the food supply. The estimated prevalence of inadequate zinc intake was correlated with the prevalence of stunting (low height-for-age) in children under five years of age (r = 0.48, P<0.001).Conclusions and SignificanceThese results, which indicate that inadequate dietary zinc intake may be fairly common, particularly in Sub-Saharan Africa and South Asia, allow inter-country comparisons regarding the relative likelihood of zinc deficiency as a public health problem. Data from these analyses should be used to determine the need for direct biochemical and dietary assessments of population zinc status, as part of nationally representative nutritional surveys targeting countries estimated to be at high risk.

Zinc supplementation reduced DNA breaks in Ethiopian women

Three studies were conducted to examine the effects of zinc concentration or source in diets of finishing beef steers. In Exp. 1, 108 (British x Continental) beef steers were supplemented with concentrations of added zinc (as ZnSO4) at 20, 100, or 200 mg/kg of dietary DM. No differences (P > 0.10) were noted among treatments for ADG or gain:feed for the 112-d finishing period. However, a linear (P < 0.10) decrease was noted in daily DMI with increasing zinc concentrations for the overall finishing period. No differences (P > 0.10) were noted in hot carcass weight; dressing percentage; longissimus muscle area; percentage of kidney, pelvic, and heart fat; or marbling score. There were, however, quadratic increases in s.c. fat thickness (P < 0.05) and yield grade (P < 0.01) with added zinc. In Exp. 2, 12 beef steers were used to examine effects of added dietary zinc on serum concentrations of cholesterol and fatty acid profiles. No differences (P > 0.10) were observed in cholesterol or fatty acids among the supplemental zinc levels. In Exp. 3, 84 Brangus- and Angus-sired steers were fed a steam-flaked corn-based diet containing 30 mg of supplemental zinc per kilogram of dietary DM from one of the following sources: 1) ZnSO4, 2) Zn amino acid complex, or 3) a zinc polysaccharide complex. No differences (P > 0.10) were noted for the overall 126-d trial for ADG, DMI, or gain:feed ratio. Percentage kidney, pelvic, and heart fat was increased (P < 0.10) in steers supplemented with ZnSO4 vs the average of Zn amino acid and Zn polysaccharide complexes. However, s.c. fat thickness was greater (P < 0.10) in steers supplemented with Zn amino acid and Zn polysaccharide complexes vs ZnSO4. Serum zinc concentration did not differ (P > 0.10) among zinc sources. Supplemental zinc concentration in finishing diets did not seem to influence feedlot performance and had a minimal impact on carcass quality. Either the organic or inorganic source can be included in finishing diets without affecting feedlot performance.

Plant‐based diets contain more folate, fibre, and phytochemicals than omnivorous diets, however some micronutrients, especially zinc, are poorly bioavailable. The findings of studies exploring the zinc intake and zinc status in populations that habitually consume vegetarian diets are inconsistent. This study aims to investigate the effects of plant‐based diets on dietary zinc intake and status in humans using systematic review and meta‐analysis techniques. Thirty‐four studies were included in the systematic review. Of these, 26 studies (reporting 48 comparisons) compared males and/or females consuming vegetarian with non‐vegetarian groups, and were included in meta‐analyses. Dietary zinc intakes and serum zinc concentrations were significantly lower (‐0.88 ± 0.15 mg/d, and ‐0.93 ± 0.27 μmol/L, P=0.001, respectively; mean ± SE) in populations that followed habitual vegetarian diets compared to non‐vegetarians. Secondary analyses showed greater impact of vegetarian diets on the zinc intake and status of females, vegetarians from developing countries, and vegans. Populations that habitually consume vegetarian diets have low zinc intakes and status. Dietary practices that increase zinc bioavailability, the consumption of foods fortified with zinc, or low dose supplementation are strategies that should be considered for improving the zinc status of vegetarians.

Population zinc (Zn) status assessment is based on serum zinc concentration (SZC) cut-offs defined by the International Zinc Nutrition Consultative Group (IZiNCG). The objective of this study is to derive reference SZC cut-offs in apparently healthy 1-19 year Indian children and adolescents using comprehensive national nutrition survey (CNNS) data, and to measure the prevalence of Zn deficiency. Apparently healthy children (n = 12,473) were selected from the CNNS, by including the highest 2 wealth quintiles, and excluding stunted, thin and obese children, and those with CRP > 5 mg/L, anaemia, hypo-albuminemia, diabetes, recent diarrhoea and history of smoking. The 2.5th centile of age-based distributions defined the SZC cut-offs, used to measure the prevalence of Zn deficiency in India, as against the IZiNCG cut-offs. The present study SZC cut-offs were significantly lower, by 10-18 µg/dL, than the IZiNCG cut-offs; more in adolescents. Prevalence of Zn deficiency in the entire CNNS, with these cut-offs, was 2.7 (<10 years) to 5.5 (10-19 years) times lower than with the IZiNCG cut-offs. No geographical state, nor any age group, had Zn deficiency as a serious public health problem (≥20%). In contrast, with IZiNCG cut-offs, 9-27 states (depending on age group) had a public health problem. The present study reference SZC cut-offs for Zn deficiency are lower than the IZiNCG cut-offs, and their rigorous selection from a national sample makes them more appropriate for use in India. A re-examination of the global applicability of IZiNCG recommended cut-offs in other LMICs appears appropriate.

Studies examining the role of zinc and copper nutriture as risk factors for cardiovascular disease in European Americans have produced conflicting results. This study assessed the associations between zinc and copper status and serum lipid levels in an adult African-American community. A cross-sectional study was conducted on 600 individuals (233 males, 367 females) from 25 to 65 yr of age using a random sampling design in a small city in Alabama. Anthropometric, dietary, and serum zinc, copper, and lipid measurements were made. The mean serum zinc and copper levels and dietary zinc intake were similar to that reported previously for European Americans. There were no significant associations between serum zinc, copper, or zinc/copper ratio and total serum cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), or triglyceride levels. For males, there was a small but significant association between dietary zinc and the total cholesterol/HDL-C ratio (r = -0.17, p = 0.03). Similarly, females taking either zinc supplements or a multivitamin including zinc had higher HDL-C values than nonsupplementing females. Further prospective studies of the relationship between zinc status and lipid levels in African Americans are needed to verify these results.

The purpose of this study was to identify the effect of oral zinc supplementation in patients with type 1 diabetes (T1DM) on metabolic control and zinc blood concentrations. The sample consisted of 20 patients with T1DM and a control group (n=17). Metabolic control was evaluated by glycemia at fast, 24 h glycosuria, and HbA1c. Zinc concentrations were measured in plasma and erythrocytes. After the first collection of biological material, oral zinc supplementation was initiated and continued for 4 mo in T1MD patients (T1). Daily dosages were established based on Dietary Recommended Intakes (DRIs), considering zinc intake based on data from other studies previously performed with this population. All analyses were repeated after supplementation (T2). Metabolic control was unsatisfactory, with an HbA1c increase at T2. There was no difference in zinc concentrations in plasma and erythrocytes between patients with T1DM and control. Zinc concentrations in plasma were within the normal range in T1MD before and after supplementation and the control. Zinc concentrations in erythrocyte presented lower than normal values for all groups. A zinc increase in erythrocyte after supplementation was observed in T1DM patients, although without statistical significance. More studies are needed to confirm oral zinc supplementation as nutritional management in diabetes.

Background Multiple micronutrient deficiencies, including zinc deficiency, remain highly prevalent among pregnant women in many low- and middle-income countries and are associated with a multitude of adverse outcomes. Objective The objectives of this analysis were to assess the impacts of prenatal multiple micronutrient supplements (MMS) compared to iron and folic acid (IFA) supplements on maternal zinc status among pregnant women at 36 weeks gestation and assess associations with birth outcomes. Methods We analyzed plasma zinc concentrations at baseline (&lt; 20 weeks gestation) and late pregnancy (36 weeks gestation) from a sub-set of pregnant women randomly assigned to receive either daily MMS (containing 30 mg/d zinc) or IFA supplements (n = 125/group) in the iLiNS DYAD trial in Ghana. Gestational and infant anthropometric outcomes were measured at birth. Results At baseline, mean + SD plasma zinc concentrations were 61.9 + 13.6 µg/dL and 16.5% of women were zinc deficient (plasma zinc concentration &lt; 50 µg/dL). At 36 weeks gestation, mean + SD plasma zinc concentrations were lower as compared to baseline, but did not differ significantly between groups (IFA: 52.2 + 8.1 µg/dL vs. MMS: 52.9 + 9.5 µg/dL; p = 0.25). Similarly, there was no difference in the estimated prevalence of zinc deficiency between groups at 36 weeks (IFA: 43.0% vs. MMS: 38.4%, p = 0.24). There were few significant associations between maternal plasma zinc concentrations or zinc deficiency and birth outcomes. Conclusions Daily MMS supplementation for &gt; 16 weeks during pregnancy did not significantly increase plasma zinc concentrations, and the prevalence of zinc deficiency increased over the course of pregnancy. Other complementary interventions to address both nutritional and underlying non-nutritional causes of zinc deficiency may be necessary to improve zinc status during pregnancy in this, and other vulnerable, populations. Registry The trial was registered as a clinical trial on ClinicalTrials.gov ( NCT00970866 ) on September 2, 2009. https://clinicaltrials.gov/study/NCT00970866 .

To determine levels of intake and food sources of zinc in 1976-80 in US adults between the ages of 19 and 74. Dietary data from 24-hour recalls collected in the Second National Health and Nutrition Examination Survey were analyzed. Levels of zinc intake were compared between demographic subgroups using analysis of variance. The contribution of individual foods to overall zinc consumed was also estimated. Mean daily intakes (+/- SEM) were 15.5 mg +/- 0.4 and 9.8 mg +/- 0.2 in white men and women, respectively. Mean daily intake estimates in black men and women (12.3 mg +/- 0.8 and 7.8 mg +/- 0.3, respectively) were significantly lower. Lower intakes were observed in women versus men, in older (65 to 74 years) versus younger (19 to 34 years) age groups, and among people with lower versus higher education and income levels. Lower zinc intakes in women and older persons could be mainly attributed to lower overall energy intake compared with gender and age counterparts. However, lower intakes in blacks and persons with lower education or income levels were not explained by differences in energy intake and may be attributed to differences in food selections. Meat and milk products contributed the majority of zinc in recalled diets, accounting for 56 and 60% of total zinc intake in blacks and whites, respectively. Levels and sources of zinc intake in 1976-80 were higher than in more recent national surveys, suggesting that zinc intakes may be declining. Population groups more likely to have lower intakes were women, older adults, blacks, and those with lower levels of education and higher poverty levels.