Effects of Exhaustion and Calcium Supplementation on Adrenocorticotropic Hormone and Cortisol Levels in Athletes
Vedat Cinar, et al.
Biol Trace Elem Res (2009) 127:1-5.
The present study was performed to investigate the effects of strenuous exercise and calcium supplementation on cortisol and adrenocorticotropic hormone levels in athletes at rest and exhaustion. Thirty male athletes, ages 17-21 years, were enrolled in the 4-week study. They were divided into three groups as follows: group 1 (n= 10): training without supplementation; group 2 (n=10): training and calcium supplemented, and group 3 (n=10): calcium supplemented without training. Venous blood samples were obtained for determination of the hormones. One-month supplementation with calcium does not influence the cortisol and adrenocorticotropic hormone in athletes, but strenuous exercise results in a significant increase in their levels with or without supplementation (p<0.05).
Plasma Leptin, Plasma Zinc, and Plasma Copper Are Associated in Elite Female and Male Judo Athletes
Lopes GC, et al.
Biol Trace Elem Res (2009) 127:109-115.
The purpose of this study was to compare plasma leptin, plasma zinc, and plasma copper levels and their relationship in trained female and male judo athletes (n= 10 women; n=8 men). Blood samples were obtained 24 h after training to measure plasma zinc, copper, and leptin levels. Subjects presented similar values to age (22±2 years old), body mass index (24±1 kg/m2), plasma zinc (l7.2±2 µmol/L), copper (12.5±2 µmol/L), and leptin (5.6± 1.3 µg/L). However, height, total body mass, lean mass, fat mass, and sum of ten skinfold thickness were higher in male than female. Plasma leptin was associated with sum of ten skinfolds in male (r=0.91; p<0.001) and female athletes (r=0.84; p<0.003). Plasma zinc was associated with leptin in males (r=0.82; p<0.05) while copper was associated with plasma leptin in females (r=0.66; p<0.05). Our results suggest that young judo athletes lost sex-related differences in leptin levels. Plasma zinc, plasma copper, and energy homeostasis may be involved in regulation of plasma leptin.
Low-dose Weekly Supplementation of Iron and/or Zinc Does Not Affect Growth Among Bangladeshi Infants
Walker CLF, et al.
Eur J Clin Nutr, (2009) 63:87-92.
To determine the effect of low-dose weekly supplementation with iron, zinc or both on growth of infants from 6 to 12 months of age. A total of 645 breastfed infants age 6 months who were not severely anemic (Hb?90gl-1) or severely malnourished (weight-for-age ? 60% median) were randomized to receive 20 mg iron and 1 mg riboflavin; 20 mg zinc and 1 mg riboflavin; 20 mg iron, 20 mg zinc and 1 mg riboflavin; or riboflavin alone (control) weekly for 6 months. Baseline characteristics were similar among the four supplementation groups. Weight, length and mid-upper arm circumference were assessed at baseline, 8, 10 and 12 months of age. There was no interaction of iron and zinc when given in a combined supplement on either weight or length (P> 0.05). There were no effects of either iron or zinc on the rate of length or weight gain for all infants or when stratified by baseline Hb concentration. Weekly supplementation of 20 mg Fe, 20 mg Zn, or both does not benefit growth among infants 6-12 months of age in rural Bangladesh, a region with high rates of anemia and zinc deficiency.
Low Serum Selenium is Associated with Anemia Among Older Adults in the United States
Semba RD, et al.
Eur J Clin Nutr, 2009 Jan; 63(1):65-70.
We hypothesized that low serum selenium was associated with anemia in humans. A total of 2092 adults aged 65 and older, in the third National Nutrition Examination Survey, Phase 2 (1991-1994) (NHANES III). Examination of the relationship between serum selenium and hematological indices in NHANES III. Anemia, defined by World Health Organization criteria, was present in 12.9%. Mean serum selenium among non-anemic and anemic adults was 1.60 and 1.51 µmoll-1(p= 0.0003). The prevalence of anemia among adults in the lowest to highest quartiles of serum selenium was 18.3, 9.5, 9.7 and 6.9%, respectively (P= 0.0005). The proportion of adults in the lowest quartile of selenium among those who were non-anemic or who had anemia due to nutritional causes, chronic inflammation, renal disease or unexplained anemia was 9.9, 27.5, 17.5, 24.0 and 15.4%, respectively. An increase in loge selenium was associated with a reduced risk of anemia (odds ratio per one standard deviation increase 0.75, 95% confidence interval 0.58-0.97, P = 0.03), adjusting for age, race, education, body mass index and chronic diseases. Low serum selenium is independently associated with anemia among older men and women in the United States.
Severe Iron Deficiency Decreases Both Bone Formation and Bone Resorption in Rats
Katsumara S, et al.
J Nutr; 2009; 139: 238-243
The purpose of this study was to clarify the manner in which dietary iron deficiency decreased bone mineral density (BMD) in rats. Eighteen 3-wk-old male Wistar rats were divided into 3 groups of 6 rats each. The rats in 2 of the 3 groups had free access to a control diet (C group) or an iron-deficient diet (ID group) for 4 weeks. The rats in the third group (PF group) were pair-fed the control diet to the mean intake of the ID group. Compared with the C and PF groups, hematocrit and hemoglobin concentrations were significantly reduced and bone mineral content and BMD of the femur were significantly lower in the ID group. Bone histomorphometric parameters showed that the bone formation rate and osteoclast surface in the lumbar vertebra were significantly reduced in the ID group compared with the C and PF groups. Furthermore, dietary iron deficiency decreased serum 1,25-dihydroxycholecalciferol, insulin-like growth factor-l, and osteocalcin concentrations and urinary excretion of deoxypyridinoline. These results suggest that severe iron deficiency decreases not only bone formation but also bone resorption.
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