The effect of zinc supplementation on body composition and hormone levels related to adiposity among children: a systematic review.

OBJECTIVE: To provide a comprehensive synthesis of the effects of Zn supplementation on childhood body composition and adiposity-related hormone levels. DESIGN: Five electronic databases were searched for randomized controlled trials of Zn supplementation studies published before 28 February 2015. No statistical pooling of results was carried out due to diversity in study designs. SETTING: Community- or hospital-based, from fourteen developing and developed countries. SUBJECTS: Children and adolescents aged 0 to 10 years. RESULTS: Seven of the fourteen studies reported an overall or subgroup effect of Zn supplementation on at least one parameter of body composition, when determined by anthropometric measurements (increased mid upper-arm circumference, triceps skinfold, subscapular skinfold and mid upper-arm muscle area, and decreased BMI). Three out of the fourteen studies reported increased mean value of total body water estimated by bio-impedance analysis and increased fat-free mass estimated by dual energy X-ray absorptiometry and by total body water. Zn supplementation was associated with increased fat-free mass among stunted children. One study found supplementation decreased leptin and insulin concentrations. CONCLUSIONS: Due to the use of anthropometry when determining body composition, a majority of the studies could not accurately address whether alterations in the fat and/or fat-free mass components of the body were responsible for the observed changes in body composition. The effect of Zn supplementation on body composition is not consistent but may modify fat-free mass among children with pre-existing growth failure.

Low serum vitamin B-12 and folate concentrations and low thiamin and riboflavin intakes are inversely associated with greater adiposity in Mexican American children.

BACKGROUND: Micronutrient status may be a contributing factor to the development of childhood obesity in many industrializing countries passing the nutritional transition. The few studies investigating associations between serum concentrations of vitamin B and intake of B vitamins with adiposity, however, have reported inconsistent findings. OBJECTIVE: The aim of the study was to examine associations between serum vitamin B-12 and folate concentrations and intakes of B vitamins with body fat by using data on 1131 Mexican American children 8-15 y of age included in NHANES 2001-2004. METHODS: Children's body mass index (BMI), trunk fat mass (TrFM), and total body fat mass (TBFM) were used as body adiposity (BA) measures. Serum concentrations of folate and vitamin B-12 were measured in blood samples collected from children. Intake of B vitamins was collected according to 24-h dietary recall. Associations of BA with serum concentrations of vitamin B-12 and folate and intake of B vitamins were determined by using linear and multinomial regression models. RESULTS: Serum concentrations of vitamin B-12 and folate were inversely associated with BMI (ß: -2.68, P < 0.01; ß = -1.33, P < 0.01), TrFM (ß:-3.32, P < 0.01; ß: -0.14, P < 0.05), and TBFM (ß:-1.93, P < 0.01; ß: -3.19; P < 0.01). Higher serum concentrations of vitamin B-12 were associated with a reduced risk of obesity (OR: 0.48; 95% CI: 0.31, 0.77; P < 0.001). Thiamin and riboflavin intakes were inversely associated with BMI (ß:-1.35, P < 0.05; ß: -1.11, P < 0.05) and TrFM (ß:-1.26, P < 0.05; ß: -1.37, P < 0.05). CONCLUSION: Similar inverse associations between BA and status of both vitamin B-12 and folate and intake of thiamin and riboflavin suggest that these micronutrients may play a role in adipogenesis and risk of childhood obesity.

Low serum concentrations of carotenoids and vitamin E are associated with high adiposity in Mexican-American children.

Mexican-American children have a high prevalence of overweight/obesity. Micronutrient deficiencies may be contributing to the development of greater adiposity in these children. This study investigated the relations between adiposity and serum concentrations of carotenoids, retinol, and vitamin E among Mexican-American children 8-15 y of age included in the 2001-2004 U.S. NHANES. Associations of the outcomes of children's body mass index (BMI), truncal fat mass (TrFM), and total body fat mass (TBFM) with serum concentrations of α-carotene, cis-ß-carotene, trans-ß-carotene, retinol, and α-tocopherol were determined by using linear, quantile, and multinomial regression models. BMI was inversely associated with serum concentrations of α-carotene (ß = -0.88, P < 0.05), trans-ß-carotene (ß = -2.21, P < 0.01), cis-ß-carotene (ß = -2.10, P < 0.01), and α-tocopherol adjusted for total cholesterol ratio (ß = -3.66, P < 0.01), respectively. Similar inverse associations were found with TrFM and TBFM. Higher cis-ß-carotene and α-tocopherol serum concentrations were associated with reduced probability of overweight (OR: 0.57; 95% CI: 0.37, 0.89; P < 0.05; and OR: 0.56; 95% CI: 0.37, 0.86; P < 0.05; respectively) and obesity (OR: 0.39; 95% CI: 0.26, 0.58; P < 0.01; and OR: 0.38; 95% CI: 0.24, 0.60; P < 0.01; respectively). Higher retinol serum concentrations were associated with increased probability of overweight and obesity (OR: 2.01; 95% CI: 1.26, 3.22; P < 0.01; and OR: 2.90; 95% CI: 1.65, 5.09; P < 0.01; respectively). Significant inverse associations were found between serum concentrations of carotenoids and vitamin E and adiposity among Mexican-American children, but serum retinol concentrations were positively associated with adiposity. Future research is needed to understand the causes and consequences of micronutrient status on adiposity and comorbidities.