Reference Values for Serum Zinc Concentration and Prevalence of Zinc Deficiency in Adult Iranian Subjects.
ABSTRACT Zinc, as an essential trace element for health, plays various biological roles in human body functions. Serum zinc reference values are essential for assessing zinc-associated abnormalities and the prevalence of zinc deficiency. This study aims at determining age- and sex-specific reference values for serum zinc concentrations in adult Iranian subjects. Serum zinc concentration was measured by flame atomic absorption spectrometry in 4,698 adult subjects, aged 20-94 years, randomly selected from the population of the Tehran, Lipid, and Glucose Study. After application of exclusion criteria, reference values for serum zinc were determined in 2,632 apparently healthy subjects according to guidelines of the International Federation of Clinical Chemistry (nonparametric method). Dietary zinc was assessed in 2,906 individuals, of which 1,685 were healthy subjects, using a validated semiquantitative food frequency questionnaire. Reference values for serum zinc concentrations ranged between 9.6 and 31.6, 8.9 and 29.9, and 9.3 and 30.8 μmol/L in men, women, and the total population, respectively. Prevalence of serum zinc deficiency was 3.0 and 2.4 % in men and women, respectively (p = 0.267); in men, but not in women, the prevalence increased significantly with age (p for trend <0.001). Of the total participants, 10.3 % (6.5 men and 3.8 % women, p < 0.01) had lower zinc intake compared to dietary reference intakes. The zinc density of the population was 6.3 mg/1,000 kcal. In conclusion, this study presents reference values for serum zinc concentration in adult Iranian subjects for both sexes and different age groups. Prevalence of serum zinc deficiency and dietary zinc inadequacy seems to be lower in Iranians, compared to some other populations.
Full-textDOI: · Available from: Firoozeh Hosseini-Esfahani, Feb 16, 2014
- 10/2014; 22(5):455-459. DOI:10.1007/s10389-014-0628-5
- [Show abstract] [Hide abstract]
ABSTRACT: Zinc (Zn) and selenium (Se) are essential trace elements involved in thyroid hormone metabolism. This study was conducted to investigate the effects of Zn and Se supplementation on thyroid function of overweight or obese female hypothyroid patients in a double-blind, randomized controlled trial. Sixty-eight female hypothyroid patients were randomly allocated to one of the 4 supplementation groups receiving Zn + Se (ZS; 30 mg Zn as zinc-gluconate and 200 μg Se as high-selenium yeast), Zn + placebo (ZP), Se + placebo (SP), or placebo + placebo (PP) for 12 weeks. Serum Zn, Se, free and total triiodothyronine (FT3 and FT4), free and total thyroxine (FT4 and TT4), thyroid-stimulating hormone (TSH), and anthropometric parameters were measured. Dietary intake was recorded using 24-hour food recall. Physical activity questionnaire was completed. No significant alterations were found in serum Zn or Se concentrations. Mean serum FT3 increased significantly in the ZS and ZP groups (p < 0.05) but this effect was significant in the ZP group compared to those in SP or PP groups (p < 0.05). Mean serum FT4 increased and TSH decreased significantly (p < 0.05) in the ZS group. TT3 and TT4 decreased significantly in the SP group (p < 0.05). Mean FT3:FT4 ratio was augmented significantly in the ZP group (p < 0.05). No significant treatment effects were found for TT3, FT4, TT4, or TSH between groups. This study showed some evidence of an effect of Zn alone or in combination with Se on thyroid function of overweight or obese female hypothyroid patients.Journal of the American College of Nutrition 03/2015; DOI:10.1080/07315724.2014.926161 · 1.68 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: OBJECTIVES: This study was designed to determine the effects of zinc supplementation on oxidative stress in hemodialysis (HD) patients through evaluating total antioxidant capacity (TAC), whole blood glutathione peroxidase (GSH) level, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) level. DESIGN AND SETTING: Double-blinded randomized controlled trialfrom October 2006 to December 2007 at Tabriz Imam Khomeini Hospital. SUBJECTS: Sixty-five HD patients were randomly enrolled into 2 groups. INTERVENTION: Patients received placebo in group A and zinc (100 mg/day) in group B for 2 months. After a washout period for 2 months, the groups were crossed over and the study was continued for an additional 2 months. MAIN OUTCOME MEASURES: Serum zinc concentration was measured using atomic absorption spectrophotometry. TAC, GSH level, and SOD activity were determined by commercial enzyme-linked immunosorbent assay kits. MDA level was measured using a thiobarbituric acid method. RESULTS: The levels of serum zinc, TAC, GSH (P < .001 for all), and SOD activity (P < .001 for group A and P = .003 for group B) significantly increased after zinc supplementation whereas the serum level of MDA decreased after the same period (P = .003 for group A and P < .001 for group B). CONCLUSIONS: Zinc supplementation for 2 months improved the serum levels of zinc, antioxidant status, and lipid peroxidation in HD patients.Journal of Renal Nutrition 11/2012; 23(3). DOI:10.1053/j.jrn.2012.08.012 · 2.55 Impact Factor