Abstract
Summary
Ingestion by healthy humans of small amounts of polyglutamate folates from yeast, equivalent to 300 μg of monoglutamate folate and containing 30 μg of “free folate,” resulted in an appreciable elevation of the serum folate corresponding to 300 μg of synthetic pteroylmonoglutamate (PGA). Ingestion of higher amounts of polyglutamate folate did not result in higher serum folate elevations than did 300 μg. It is concluded that small amounts of polyglutamate folate from yeast are fully utilized, presumably by deconjugation in the gut prior to absorption. The relative ineffectiveness of larger doses of polyglutamate folates from yeast may be due to limiting conjugase activity in the gut, unfavorable conditions for its activity (such as unsuitable pH) or to an inhibitor of the enzyme present in impure preparations.
The able technical assistance of Mrs. M. Jablonska, H. Barromi, and M. Ben-Basat is gratefully acknowledged. This investigation received financial support from the World Health Organization, Geneva, and from the Ministry of Health, Government of Israel, Jerusalem.
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