Giving mothers and children in developing countries twice the WHO recommended doses of vitamin A, as suggested by an international vitamin group, does not have a beneficial effect.
The findings are reported in an Article published in this week’s edition of The Lancet.
Providing vitamin A supplementation in countries where there is a deficiency of the vitamin has been proven to decrease mortality. As a result, most developing countries have adopted a standard WHO (World Health Organisation) dosing schedule for vitamin supplementation. However, in 2002, the International Vitamin A Consultative Group (IVACG) Annecy Accord recommended a new high-dose regimen for mothers and infants.
Professor Andrew Prentice, International Nutrition Group, London School of Hygiene and Tropical Medicine, UK, and colleagues studied 220 women-infants pairs in an area of moderate vitamin A deficiency in Gambia. One group received the WHO recommended dose, while the other received the IVACG recommended dose. Blood plasma levels of vitamin A, incidence of Helicobacter pylori infection, nasopharyngeal pneumococcal carriage, and infant guy epithelial integrity were all tested, and no significant differences were found between the two groups.
The authors conclude: “Our results do not lend support to the proposal to increase the existing WHO standard dosing schedule for vitamin A in areas of moderate vitamin A deficiency. Caution is urged for future studies because trials have shown possible adverse effects of higher doses of vitamin A, and potential negative interactions with the expanded programme on immunisation (EPI) vaccines.”
Both the Article and an accompanying Comment refer to previous studies in which vitamin A doses lower, rather than higher, than the WHO recommendation were trialled. The results suggested better or at least equal protection against mortality in young infants could be achieved with these lower doses.
The comment, by Professor Bernard Brabin, Child and Reproductive Health Group, Liverpool, UK and also Emma Kinderziekenhuis (Emma Children’s Hospital), Academic Medical Centre, University of Amsterdam, Netherlands, says: “Further investigation of doses lower than the standard WHO dose and studies in areas with high vitamin A deficiency should be encouraged.”
It concludes: “Additionally, future trials should emphasise the importance of exclusive breastfeeding, because early feeding with formula milk might reduce potential benefits from early supplementation with vitamin A in infants.”