Increases in blood folate indices are similar in women of childbearing age supplemented with [6S]-5-methyltetrahydrofolate and folic acid

Bernard J. Venn, Timothy J. Green, Rudolf Moser, Joanne E. Mckenzie, C. Murray Skeaff, Jim Mann

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The natural diastereoisomer [6S]-5-methyltetrahydrofolate ([6S]-5-MTHF) may be a safer fortificant than folic acid for neural tube defect (NTD) prevention because it is unlikely to mask vitamin B-12 deficiency. An inverse relationship between NTD risk and blood folate concentrations has been reported. In this randomized, placebo-controlled, double-blind trial, we compared the effects of [6S]-5-MTHF and folic acid supplementation for 24 wk on plasma folate and red cell folate (RCF) in women of childbearing age (18-49 y). Women (n = 104) were randomly assigned to receive a supplement containing [6S]-5-MTHF (113 μg/d), folic acid (100 μg/d) or placebo. The mean estimated linear increase in plasma folate concentration was 0.3 [95% confidence interval (Cl): 0.1, 0.5], and 0.4 (0.2, 0.6) nmol/(L·wk) in the [6S]-5-MTHF and folic acid groups, respectively. The mean estimated linear increase in RCF was 7.4 (95% Cl: 4.5, 10.3), and 8.3 (4.4, 12.3) nmol/(L·wk) in the [6S]-5-MTHF and folic acid groups, respectively. There were no differences in the slopes between the [6S]-5-MTHF group and the folic acid group in either plasma folate (P = 0.48) or RCF (P = 0.70). At 24 wk, estimated mean increases in plasma folate concentrations were 6.9 (95% Cl: 1.7, 12.2) and 9.2 (3.3, 15.1) nmol/L, and in RCF, 251 (143, 360) and 275 (148, 402) nmol/L, in the [6S]-5-MTHF and folic acid groups, respectively, relative to the placebo group. These data suggest that low dose [6S]-5-MTHF and folic acid supplementation increase blood folate indices to a similar extent. A steady state in the blood indices had not been reached by 24 wk.

Original languageEnglish
Pages (from-to)3353-3355
Number of pages3
JournalJournal of Nutrition
Issue number11
Publication statusPublished - 1 Nov 2002


  • Folic acid supplementation
  • Plasma folate
  • Red blood cell folate
  • Women
  • [6S]-5-methyltetrahydrofolate supplementation

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

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