In May 2019 researchers from Singapore published the results of their review of the medical scientific literature to assess the effects of fortifying staple foods (sugar, edible oils, edible fats, maize flour or corn meal, wheat flour, milk and dairy products, and condiments and seasonings) with vitamin A for reducing vitamin A deficiency and improving health-related outcomes. A total of ten studies lasting between three to nine months and involving 4,455 individuals from countries where vitamin A deficiency is a public health issue were included in the review. Results showed that fortifying staple foods with vitamin A alone may make little or no difference to retinol levels or the risk of vitamin A deficiency, although it was found that if the fortification was with vitamin A plus other micronutrients retinol levels may increase and the risk of vitamin A deficiency reduced. However, it should be noted that the certainty of the evidence was mainly affected by risk of bias which was assessed as high. Further research is required.
Hombali AS et al. Fortification of staple foods with vitamin A for vitamin A deficiency. Cochrane Database Syst Rev. 2019 May 10;5:CD010068