American Journal of Clinical Nutrition, Vol 22, 733-739, Copyright © 1969 by The American Society for Clinical Nutrition, Inc.

Hematologic Response to Physiologic Doses of Folic Acid in Tropical Sprue

¹ From the Department of Medicine, University of Puerto Rico School of Medicine, San Juan, Puerto Rico 00905

The minimum daily requirement for folic acid has been estimated to be 50 µg. The minimum daily dose to which tropical sprue patients respond has been quoted as 25 µg. We report our recent experience with 22 patients with tropical sprue given doses ranging from 25 to 220 µg daily. A hematologic response was observed in only three patients who were given 100 µg of crystalline folic acid with a thrice-boiled diet that had a low folate content and a lesser binding capacity. The remaining 19 patients failed to respond. The latter included 15 patients who received 100 µg of folic acid for 10 days. It is our belief that besides variable degrees of absorption, variations in serum and tissue stores of folic acid and vitamin B₁₂ make it difficult to establish minimal requirements of folic acid for a hematologic response to occur in patients with tropical sprue. However, we have not observed in any single patient with tropical sprue a response to doses of crystalline folic acid of less than 100 µg/day.