Bioavailability for Humans of Deuterium-Labeled Monoglutamyl and Polyglutamyl Folates Is Affected by Selected Foods

摘要: Dietary folate exists mainly as polyglutamyl forms that require deconjugation by Zn-dependent pteroylpolyglutamate hydrolase prior to intestinal absorption. Because is an essential step in the absorption of dietary folates, factors influencing deconflugation process may affect bioavailability. This study was conducted evaluate vivo bioavailability [ 2 H 4 )folic acid (d -PteGlu 1 ) and ]-pteroylhexaglutamate 6 administered solution water or citrate buffer added selected foods using a single-dose, dual-label protocol. In each six trials, healthy men (n = 7) were given single oral dose d (677 nmol form) blended into orange juice, tomatoes, lima beans, 52 mmol/L (pH 4.1), control. Urine collected for 48 h isotopic labeling urinary folates used criteria relative PteGlu . Urinary excretion -folates derived from respective doses did not differ control any treatment within statistical power this High reflected ratios /d ∼ 1.0 control, tomato, bean whereas ratio when subjects consumed juice ∼33% less than (P < 0.05). These findings suggest would be partially incomplete. However, compensated high total concentration orangejuice. The relation these endogenous requires further investigation.