The supply of bioavailable iron and zinc may be affected by phytate in Beninese children

Mitchikpe, C.E.S.; Dossa, R.A.M.; Ategbo, E.A.D.; van Raaij, J.M.A.; Hulshof, P.J.M.; Kok, F.J.


Food composition data are important for estimating energy and nutrient intakes. The objectives of this study were, first, to evaluate the proximate and inorganic composition of foods eaten in northern Benin and second, to estimate the potentially inhibiting effect of phytate on iron and zinc bioavailability. Chemical analyses were performed in 23 samples of most frequently consumed foodstuffs collected from retailers in local markets. Proximate composition was analysed by routine methods. Inorganic constituents and phytate were analysed using ICP-AES and HPLC. Protein contents were in agreement with those in FAO food composition database. Fat and fibre were in general higher whereas carbohydrate and energy were lower. Differences were mainly due to analytical or calculation methods. The most important sources of iron and zinc in children's diets were maize, sorghum and millet. In these cereals, iron and zinc ranged from 2.6 to 8.4 and 2.2 to 3.4 mg/100 g, respectively. Phytate ranged from 104 to 503 mg/100 g. Phytate/iron and phytate/zinc molar ratios ranged from 1 to 11 and 3 to 22, respectively. They suggest poor iron and zinc bioavailability. Reducing phytate and polyphenol contents in order to improve iron and zinc bioavailability from the most frequently consumed cereal food needs to be studied.