Conclusion
This study challenges the assumption that 6 mg dietary bcarotene provides 1 RE. The mean apparent effectiveness of fruit in improving vitamin A status was 50% (95% CI: 21%, 100%) whereas that of dark-green, leafy vegetables and carrots was 23% (8%, 46%) of that assumed previously. This has important implications for the choice of strategies for controlling vitamin A deficiency. The role of vitamin A capsules should not be underestimated and dietary diversification should, wherever possible, specifically aim at increasing the intake of vitamin A from fruit, animal food, and fortified food and at maximizing the bioavailability of carotenoids from dark-green, leafy vegetables.The large range of apparent effectiveness found for fruit (21–100%) and dark green, leafy vegetables (8–46%) in increasing serum retinol concentrations prompts research on ways of quantifying and improving the bioavailability and bioconversion of dietary carotenoids, focusing on the effect of factors such asintestinal parasite infestation, the food matrix, absorption
inhibitors, and bioconversion inhibitors.