The studies with the 14 subjects were conducted using folic acid labeled with nonradioactive isotopes of carbon and hydrogen.
Of the seven trials, the first five were conducted to evaluate how well the isotope-labelled folic acid in either water (the control substance) or in the different experimentally fortified grain products was absorbed into the bloodstream. The investigators conducted the final two trials to study a liquid supplemental dose of folate consumed either with or without a light breakfast.
The research team analyzed serum and red blood cell folate concentrations of the 14 participants by microbiological assay. Also, the total folate concentration of urine was measured by high pressure liquid chromatography.
"On the basis of our findings, fortified cereal grain products appear to be highly effective as sources of bioavailable folic acid," said Dr. Gregory.
Following preparation and before serving the fortified cereal grain products, he added, the team found the retention of added folic acid in the white bread to be 70%, the wheat bread 67%, the rice 86%, and the pasta 46%.
In addition to their cereal grain findings, the researchers concluded that folic acid consumed as a vitamin supplement either without food or with a light breakfast is absorbed in a fashion similar to that noted for the cereal grains.
The folate research was sponsored by the U.S. Department of Agriculture--National Research Initiative Competitive Grants Program.
Commenting on the folic acid study for an editorial in the same issue of the monthly
peer-reviewed journal of the American Society for Clinical Nutrition, Tsunenobu Tamura, M.D.,
Professor of Nutrition, Department of Nutrition Sciences, University of Alabama at Birmingham,
said: "Considering the information available, it is reasonable to conclude that folic acid added to
cereal-grain products is bioavailable to a certain extent or is close to that of folic acid
supplemented alone. Th
Contact: Jesse F. Gregory, III, PhD
American Society for Clinical Nutrition/American Society for Nutritional Sciences