The Labile Folate of Milk

Abstract

Milk contains an appreciable amount of free folic acid activity. Applying destructive oxidation procedures, it appears that the free folic acid activity is made up by a labile and a stable fraction, plus a fraction of intermediate lability. Powdered milk has less free folic acid activity than farm or pasteurized milk. The free folic acid activity of powdered and pasteurized milk is more susceptible to the damaging effects of heating. The present study suggests that the megaloblastic anemia induced in monkeys by May and collaborators twenty years ago, and which was ascribed to ascorbic acid deficiency, was in fact due to the associated folic acid deficiency produced by feeding the monkeys boiled powdered milk. The results also suggest that perhaps milk should be enriched with ascorbic acid before processing, if its folic acid activity is to be protected. Or, when the processed milk is intended for infant use, an adequate intake of folic acid should be assured by adding pteroyl-glutamic acid (PGA) to the milk, either before or after processing.