Micronutrients and women of reproductive potential: required dietary intake and consequences of dietary deficiency or excess. Part II--vitamin D, vitamin A, iron, zinc, iodine, essential fatty acids

Abstract

Part II of this review considers additional micronutrients. Vitamin D is a fat soluble vitamin found in foods of animal origins (fatty fish, liver oil) or fortified products (milk, cheese). Vitamin D deficiency is common in African-American women living in northern latitudes. Vitamin D supplementation may be needed to reach desired 25-(OH)D3 concentrations of >50 nmol/L. In foods of animal origin, preformed Vitamin A is present; in plants (fruits and vegetables) vitamin A precursors (β-carotenoids) are present. Vitamin A supplementation is usually not warranted, and in developing countries should not exceed 3000 μg (10,000 IU)/day. Iron in the form of haem-iron is found in meat, fish and poultry; non-haem (inorganic) iron is found in vegetables, fruits and grains. Iron supplementation may be necessary in the third trimester, earlier in pregnancy or in non-pregnant states if serum ferritin is <20 μg/L or haemoglobin <10.9 g/dL. Zinc is available in red meat, seafood including oysters and unpolished grains; supplementation is not necessary. To assure adequate iodine, food is fortified worldwide with iodated salt. If urinary iodine levels are low, supplementation is needed. Essential fatty acids requirements can be met by one to two portions of fish per week.