Short-term serum and red blood cell folate responses to folate intake by women

Abstract

To determine short term responses in serum folate (SF) and red blood cell folate (RBCF) concentrations, a low folate (170 nmol total folate) and high folate (low folate diet plus 910 nmol pteroylglutamic acid [PGA]) diet were each provided for one week periods to 12 female volunteers 22 to 41 years of age. Six of the subjects were users of oral contraceptive agents (OCA) and the other six were not (non-OCA). During a preliminary week, subjects consumed a self-selected diet and kept detailed dietary records. SF was measured on days 3, 5 and 7 of each week while RBCF and hematocrit were measured on day 7 of each week. Mean SF was lower (P<.01) with the low than the high folate diet (18 vs 27 nmol/L) by day 7 of each period. Mean RBCF was not markedly altered by folate intake (520 vs 540 nmol/L for the low and high folate diets, respectively). Percentage change in individual SF but not RBCF was significant (P<.01) between treatments. RBCF was lower (P<.05) during the preliminary week and SF was lower (P<.02) during both treatment periods for OCA than non-OCA. SF responses to very short term changes in folate intake, indicate that values should be interpreted with an awareness of the extent to which very recent folate intake represents usual intake.