Fortification has several potential risks

EDITOR—Wharton and Booth recommend caution and carrying out a field trial before a policy of fortifying flour with folic acid is implemented, but both they and the Department of Health's report understate the potential risks of the policy to the nervous system.1

In people with vitamin B-12 deficiency, giving folic acid does much more than mask any anaemia. The response of pernicious anaemia to folic acid is usually suboptimal and temporary and often followed by relapse. The vitamin precipitates not only neurological complications, sometimes after some initial temporary improvement, but also anaemia, although not necessarily to the same degree or in the same time scale. 2 3

Can these problems with usually pharmacological doses of folic acid (1-50 mg daily) be avoided with minimum food fortification? The only evidence I know of is a review of 38 patients with vitamin B-12 deficiency treated with 1 mg folic acid, 30% of whom showed a significant haematological …