The bioavailability of (pro) vitamin A carotenoids and maximizing the contribution of homestead food production to combating vitamin A deficiency.

An estimated 100-140 million children worldwide suffer vitamin A deficiency disorders (VADD). Strategies for combating VADD are best used in combination because they serve particular target groups and none has full coverage. Homestead food production (HFP) can contribute to combating vitamin A deficiency directly, by increasing intake of vitamin A-rich foods, and indirectly through improving health and increasing income. By the late 1990s, conversion factors for estimating vitamin A obtained from plant foods were revised from 6:1 to 12:1 (microg beta-carotene:retinol activity equivalent) by the U.S. Institute of Medicine, and by West and colleagues to 21:1 for a mixed diet (12:1 for fruits and 26:1 for vegetables). Thus, plant foods contribute less to vitamin A intake than do other sources. HFP's contribution can be maximized by increasing the amount of vitamin A-rich food consumed, including animal source foods, choosing foods with higher vitamin A content, and improving bioavailability by adding fat, destroying the matrix of vegetables, and deworming. Since the early 1990s, HFP programs have also included nutrition education and were then generally successful in increasing vitamin A intake. However, impact on vitamin A status was not often accessed. Two examples of evaluating impact using a plausibility approach are described. It is concluded that HFP can make a valuable contribution to combating VADD, especially where dietary diversity is low and when animal husbandry and nutrition education are included. Impact can be further maximized by using program infrastructure to introduce micronutrient-rich cultivars and improved breeds, and by adding other interventions, such as deworming and micronutrient supplementation.