Serum extracellular superoxide dismutase activity as an indicator of zinc status in humans.

Zinc is one of the essential micronutrients in the geriatric population, but the importance of zinc status and dietary zinc intake has been poorly characterized. We aimed to explore the relationships among dietary zinc intake, serum zinc concentrations and multimorbidity in a cross-sectional study of 300 employees of Electric Generating Authority of Thailand aged ≥ 60 years. Comprehensive questionnaires were completed, and clinical and laboratory assessments were performed. Factors associated with low serum zinc concentrations were identified using multivariate multinomial logistic regression analyses. The mean serum zinc level was 80.5 (12.8) µg/dL. After adjustment for baseline characteristics, being female and having been in education for ≤12 years were independent risk factors for the lowest tertile (T1) of serum zinc. After additional adjustment for clinical and biochemical parameters, there was a significant association between depression (Thai Geriatric Depression Scale-15 score > 5) and low serum zinc levels (T1 vs. T3, odds ratio (OR): 2.24; 95% confidence interval (CI): 1.06–4.77). Furthermore, as serum albumin increased, serum zinc concentration substantially increased (T1 vs. T3, OR: 0.01; 95% CI: 0.002–0.070). Therefore, the early detection of risk factors and the further management of depression and low serum albumin may assist physicians in preventing low serum concentrations.

The role of zinc deficiency as an important cause of morbidity and impaired linear growth has prompted the need to identify indicators of population zinc status. Three indicators have been recommended - prevalence of zinc intakes below the estimated average requirement (EAR), percentage with low serum zinc concentrations, and percentage of children aged < 5 years who are stunted. This review outlines steps to estimate the prevalence of inadequate intakes, and confirm their validity based on the EARs set by International Zinc Nutrition Collaborative Group. Next, the appropriateness of serum zinc as a biochemical marker for population zinc status is confirmed by a summary of: (a) the response of serum zinc concentrations to zinc intakes; (b) usefulness of serum zinc concentrations to predict functional responses to zinc interventions; (c) relationship between initial serum zinc and change in serum zinc in response to interventions. Height- or length-for-age was chosen as the best functional outcome after considering the responses of growth, infectious diseases (diarrhoea, pneumonia), and developmental outcomes in zinc supplementation trials and correlation studies. The potential of other zinc biomarkers such as zinc concentrations in hair, cells, zinc-metalloenzymes, and zinc-binding proteins, such as metallothionein, is also discussed. Molecular techniques employing reverse transcriptase (RT)-polymerase chain reaction to measure mRNA in metallothionein and ZIP1 transporter hold promise, as do kinetic markers such as exchangeable zinc pools (EZP) and plasma zinc turnover rates. More research is needed to establish the validity, specificity, sensitivity, and feasibility of these new biomarkers, especially in community-settings.

Association between urinary zinc excretion and lymphocyte dysfunction in patients with lung cancer

Zinc deficiency: A complication of Crohn's disease

The absorption of zinc from a standardized meal in alcoholics and in normal volunteers

Effect of zinc supplementation on serum zinc concentration and T cell proliferation in nursing home elderly: a randomized, double-blind, placebo-controlled trial

Red Meat and a Fortified Manufactured Toddler Milk Drink Increase Dietary Zinc Intakes without Affecting Zinc Status of New Zealand Toddlers1–4

Plant-based diets contain less saturated fat and cholesterol and more folate, fibre and phytochemicals than omnivorous diets, but 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 diets 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 day(-1), P < 0.001 and -0.93 ± 0.27 µmol L(-1), P = 0.001 respectively; mean ± standard error) in populations that followed habitual vegetarian diets compared with 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. Not all vegetarian categories impact zinc status to the same extent, but a lack of consistency in defining vegetarian diets for research purposes makes dietary assessment difficult. 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 with low zinc intakes or serum zinc concentrations at the lower end of the reference range.

Serum copper and zinc concentrations are lower in Iranian patients with angiographically defined coronary artery disease than in subjects with a normal angiogram

The associations among dietary zinc intakes and biomarkers of zinc status are unknown in apparently healthy children at high risk for zinc deficiency. To assess associations among zinc-related parameters in a sample of Guatemalan school-aged children. We assessed total dietary intakes and biomarkers of zinc status before and after receiving 6 months of zinc supplementation or placebo in 691 Guatemalan schoolchildren aged 6 to 11 years. Most of the children also received zinc-fortified milk from a government program that started shortly after the trial began. We assessed associations between zinc intakes and serum zinc, alkaline phosphatase (ALP), and albumin. At baseline, the prevalence of serum zinc < 65 microg/dL and dietary zinc intake below Estimated Average Requirements (EAR) (< 4 and < 7 mg/day for children < 9 and > or = 9 years, respectively) were 21.6% and 39.4%, respectively. Pearson correlations between serum zinc concentration and dietary zinc intake, serum ALP, and serum albumin were r = 0.07, 0.15, and 0.07, respectively. At the 6-month follow-up, low serum zinc and low total (diet plus fortified milk) zinc intakes were observed in 1.2% and 0.0% of children in the zinc-supplemented group and 4.0% and 34.1% in the placebo group, respectively. Pearson correlations between serum zinc concentration and total zinc intake, serum ALP, and serum albumin were 0.10, 0.06, and -0.11 in the zinc-supplemented group and -0.04, 0.05, and 0.01 in the placebo group, respectively. Zinc intake was inconsistently associated with markers of serum zinc concentration. Zinc fortification or supplementation attenuated the associations.

Behavioral and dermatologic changes and low serum zinc and copper concentrations in two premature infants after parenteral alimentation

Serum zinc and serum copper concentrations during early pregnancy in 84 consecutive primigravidae were correlated to other haematological factors and were also correlated to complications of labour and/or complications affecting the infant. In women with complications such as abnormal labour or atonic bleeding, serum zinc concentrations were significantly reduced (p less than 0.001) during early pregnancy. Women who gave birth to immature infants also showed significantly lower serum zinc in early pregnancy (p less than 0.01). Women delivered in the 37th week or earlier or in the 43rd week or later showed significantly lower serum zinc during early pregnancy (p less than 0.005) compared to women delivered in the 40th week. One infant showed a congenital heart defect (ventricular septum defect and preductal coarctation of aorta). Her mother showed the lowest serum zinc concentration recorded in the 13th week, but no other abnormal findings. Compared to women with abnormal labours and/or immature infants, mothers with normal deliveries and normal deliveries and normal infants showed significantly higher serum zinc values (p less than 0.001) and significantly lower serum copper concentrations (p less than 0.025) during early pregnancy. A notably high incidence of complications affecting mothers and infants has been recorded among women with low serum zinc. Similarities to effects of experimental zinc deficiency in animals are striking. If a low serum zinc reflects a state of deficiency, and this seems to be the case, zinc deficiency is probably common.

Serum Zinc Concentrations in the US Population Are Related to Sex, Age, and Time of Blood Draw but Not Dietary or Supplemental Zinc

Abnormal serum zinc and copper concentrations in pregnant women have been associated with a number of maternal and foetal complications during pregnancy and delivery. However, the results of previous studies are contradictory and few large scale studies have been reported. In this study we measured serum zinc and copper concentrations in maternal and umbilical cord blood from 500 Danish mothers at delivery, looking for an association between serum zinc and copper levels and various maternal and foetal complications. Preterm infants (n = 30) had significantly lower serum copper concentrations than reference infants (n = 346) (p = 0.01), whereas there was no difference in serum zinc concentrations. Mothers of preterm infants (n = 34) did not differ in serum zinc or copper concentrations from reference mothers (n = 220). Small for date infants (n = 37) and mothers of small for date infants (n = 47) had higher serum copper levels than reference infants and mothers (p = 0.02 and p = 0.04, respectively), whereas there was no difference in serum zinc concentrations. Serum zinc and copper concentrations in malformed infants (n = 14) and their mothers (n = 17) did not differ from concentrations in reference infants and mothers. Serum zinc and copper concentrations in mothers with various other complications during pregnancy and delivery did not differ from values in mothers with normal pregnancies and deliveries.

The effects of zinc supplementation on serum zinc and cholesterol concentrations in hemodialysis patients