Folate clinical trials

Assessing Colonic Folate Absorption & Metabolism

Folate, a B-vitamin, is necessary in metabolic processes such as amino acid and nucleotide synthesis. Since folate cannot be synthesized by mammals, it must be consumed as foods and dietary supplements or generated by bacteria present in the colon. There are many known adverse health outcomes associated with folate deficiency in humans such as neural tube defects in newborns and colorectal cancer in adults. It has also been proposed that supra-physiological folate status can also be detrimental since it can lead to changes in immune function and the masking of vitamin B12 deficiency. It is generally believed that dietary sources of folate are primarily absorbed in the small intestine, however recent evidence suggests the colon may play a more significant role in the absorption of folate than previously understood. The aim of this study is to assess how folic acid supplementation influences colonic folate absorption and metabolism in humans. This will be accomplished by assessing the expression of two major folate transporters responsible for folate absorption in the colon. Participants will be randomized to receive multivitamins with either 0 or 400 µg folic acid during a 16-week randomized clinical trial in which blood and colonic tissue biopsies will be collected and analyzed. The total folate concentrations and expression of folate transporters in colonocytes will be measured to confirm levels and evaluate the impact of supplemental folic acid. The expression of two folate hydrolases responsible for converting naturally occurring folate to its bioavailable form will also be evaluated. This work will lead to a deeper understanding of colonic folate absorption and metabolism, resulting in more appropriate dietary and supplemental folate recommendations.