Stable Isotopes: The Method of Choice to Assess Vitamin A Interventions

The tragic consequences of vitamin A deficiency (blindness, illness, and premature death) have stimulated extensive efforts to prevent this deficiency. Perhaps most notable in scope and influence is the WHO's recommendation since 1998 that high-potency supplements should be given every 4–6 months to children 6 to 59 months old who live in the affected regions of the world. The WHO estimates that 1.25 million deaths in 40 countries have been averted by this programme. Many of these countries have also addressed the problem by fortifying commonly consumed foods, such as cooking oil or sugar. Agricultural programmes have developed both biofortified and genetically modified foods with increased vitamin A content.