The Institute of Medicine (IOM), WHO and the European Food Safety Authority (EFSA)have each issued a set of vitamin A recommendations with diverging values and provitamin A conversion factors, expressed either as retinol equivalents (RE) or retinol activity equivalents (RAE). We present here a case-study by comparing these recommendations for lactating women from rural Guatemala.
Dietary intake data were collected by 24h recall from 55 lactating women, and the proportion of provitamin A intake was calculated using the USDA food composition table. Vitamin A intake recommendations were subsequently compared among the three institutions.
The proportion of provitamin A intake in the diet of these lactating women from rural Guatemala was 45%. Assuming that 2/3 of provitamin A intake is in the form of all-trans ß- carotene and 1/3 as other provitamin A carotenoids, the recommended intake (in µg) of preformed retinol and pro-vitamin A carotenoids, respectively, would be 468 and 3060 by WHO (RE); 715 and 4680 by EFSA (RE); and 715 and 9360 µg by IOM (RAE).
Estimated compliance with vitamin A intake recommendations for lactating women varies greatly across these three international, authoritative institutions, especially when the proportion of provitamin A intake in the diet is large. This is due to a mismatch between the units of recommendation by WHO and EFSA (RE) and those of the IoM and USDA food composition table (RAE), frequently used adjacently to assess adequacy of vitamin A intake in developing countries. Harmonization of vitamin A intake recommendations with food composition values for international use is urgently required.