Zinc and phytate intake of rural Gambian infants: contributions from breastmilk and weaning foods

Zinc and phytate intakes of 183 rural Gambian infants were obtained from weighed records of breastmilk and food intake and measured contents in foods. Total zinc intake of 2.7 mg/d in the first month of age declined to 1.5 mg/d at 3 months, then increased to 4.3 mg/d by 17 months. Breastmilk was an important source of zinc, but the predominant cereal and groundnut-based foods had high [phytate]/[Zn] molar ratios ranging from 13 to 28, indicating potential impaired zinc bioavailability. The [phytate]/[Zn] molar ratio for the diet as a whole was low in early infancy, but increased to 13 in the second year. In contrast, this ratio was less than 6 for the diet of 48 Cambridge breastfed infants up to 18 months. A further disadvantage to the Gambian infants was indicated by their lower intake of protein of animal origin. However, calcium intake was estimated in both communities to be below the level which could give rise to zinc chelation in association with phytate. Compared to 'basal' and 'normative' requirements, total zinc intake of the Gambian infants showed the greatest shortfall between 3 and 12 months, making this the age band for maximum probable benefit from focused intervention programmes.