More evidence is needed before general supplementation

doi:10.1136/bmj.39619.480694.3A

BMJ 2008;336:1451 (28 June), doi:10.1136/bmj.39619.480694.3A

Letters

Vitamin D deficiency

More evidence is needed before general supplementation

The first 150 words of the full text of this article appear below.

Holick is right to highlight the high prevalence of vitaminD insufficiency in many groups of people living at higher latitudes.¹However, the evidence base to support general supplementation,including aggressive fortification, does not currently exist.

An impressive array of observational data suggests that lowvitamin D concentrations are associated with a wide varietyof diseases, including diabetes, cardiovascular disease, andcancer. This does not necessarily mean that intervention withvitamin D supplementation will improve health outcomes—witnessthe problems of hormone replacement therapy despite encouragingobservational data, not to mention the lack of effect and possibleharms surrounding vitamins A, E, and β carotene supplementation.²

Although traditional vitamin D toxicity may be unlikely evenwith relatively large doses of vitamin D, we cannot be surethat long term vitamin D supplementation does not in fact causesome harms—and the case for benefits is far from proved.The recent women’s health . . . [Full text of this article]

Miles D Witham, clinician scientist, ageing and health

¹ University of Dundee, Ninewells Hospital, Dundee DD1 9SY