What are the main results of the review?
The review authors found 10 relevant studies (involving 4455 participants) from China, India, the Philippines, Bangladesh, Thailand, and Mexico. Three studies provided one study group with staple foods fortified with vitamin A alone, and another group with the same unfortified staple foods. Five studies compared staple foods fortified with vitamin A plus other vitamins and minerals versus the same unfortified staple food, and two studies compared staple foods fortified with vitamin A plus other vitamins and minerals versus no intervention.
No studies compared staple foods fortified with vitamin A versus no intervention.
Government agencies, private agencies, non‐governmental organisations, the private sector, and academic institutions funded the studies. The source of funding does not appear to have distorted the results.
The effect of fortification of staple foods with vitamin A alone on vitamin A stores and on subclinical vitamin A deficiency is uncertain. It is uncertain whether this intervention might reduce clinical vitamin A deficiency (night blindness).
The review authors are moderately confident that fortifying staple foods with vitamin A and other micronutrients may not improve vitamin A status. However, children and adolescents in low‐ and middle‐income populations who eat foods fortified with vitamin A and other micronutrients may have a lower risk of subclinical vitamin A deficiency compared to those receiving unfortified staple foods.
We do not know how vitamin A fortification affects other health indicators, such as the rate of disease in the population, mortality, adverse effects, food intake, birth defects (for pregnant women), or breast milk concentration for lactating women. The review authors considered six of the included studies to be of poor methodological quality.
The review authors searched for published studies up to July 2018.
Read the full review here