Cereal grains with little vitamin A content are often staple foods for populations at greatest risk of VAD. Biofortification of staple crops has emerged as a potential long-term, sustainable approach to increase provitamin A content in high-staple food diets and a complement or alternative to supplementation in efforts to alleviate VAD (8). Maize (Zea mays) is a biofortifi- cation target due to its high consumption, particularly in Africa (9,10). Most provitamin ?-enhanced maize contains mainly /3-carotene, but some varieties have increased /3-cryptoxanthin content (11,12). Provitamin A carotenoids must be cleaved in the intestine by /3-carotene monooxygenase, allowing for regula- tion of carotenoid bioconversion to retinol (13). Thus, bioforti- fication poses no risk of toxicity, due to increasing provitamin A carotenoids instead of preformed retinyl esters used in fortifica- tion programs (8). Maize biofortified with provitamin A im- proved the retinol status of depleted gerbils (9) and efficient bioconversion factors were obtained in 2 small human trials (14,15). However, to date, no studies to our knowledge have observed the impact of feeding a biofortified food during gestation and lactation on offspring retinol status.