iron Community and International Nutrition anemia pregnancy vitamin A Mexico NHANES III birth aize blood lipids body composition cardiovascular disease risk contraceptive use diet assessment dietary intakes dietary supplements docosahexaenoic acid ferritin fertility growth growth retardation human capital 2002-04 study in Guatemalan iron deficiency iron stores lipid metabolism meta-analyses micronutrient supplementation micronutrients minerals and phytochemicals multimicronutrient multivitamin-mineral multivitamins nutritional neurosciences pregnancy and lactation premenopausal women preschool children vitamins weight gain women