[6S]-5-Methyltetrahydrofolate is at least as effective as folic acid in preventing a decline in blood folate concentrations during lactation.
BACKGROUND
Studies in nonpregnant, nonlactating women suggest that folate supplementation in the form of 5-methyltetrahydrofolate ([6S]-5-methylTHF) is at least as effective as folic acid in increasing blood folate indexes. No data, however, are available on the effect of supplemental [6S]-5-methylTHF on blood folate concentrations during lactation.


OBJECTIVE
We assessed the relative effectiveness of [6S]-5-methylTHF, a placebo, and folic acid in maintaining blood folate indexes during lactation in a sample of healthy Canadian women consuming folic acid-fortified foods.


METHODS
This study was designed as a 16-wk, randomized, placebo-controlled intervention. Pregnant women (n = 72) advised to consume a folic acid-containing prenatal supplement (1000 microg/d) during pregnancy were enrolled at 36 wk gestation. After delivery, the women were randomly assigned to receive [6S]-5-methylTHF (416 microg/d, 906 nmol/d) or a placebo or were assigned to a folic acid (400 microg/d, 906 nmol/d) reference group.


RESULTS
At 16 wk of lactation, the mean red blood cell (RBC) folate concentration in women in the [6S]-5-methylTHF group (2178; 95% CI: 1854, 2559 nmol/L) was greater than that in the folic acid (1967; 1628, 2377 nmol/L; P < 0.05) and placebo (1390; 1198, 1613 nmol/L; P < 0.002) groups after adjustment for baseline concentrations (36 wk gestation). The distribution of folate forms in RBCs did not differ significantly between the [6S]-5-methylTHF and placebo groups. However, the folic acid group had greater amounts of 5-formylTHF (P < 0.03).


CONCLUSIONS
[6S]-5-MethylTHF appeared to be as effective as, and perhaps more effective than, folic acid in preserving RBC folate concentrations during lactation.
Houghton
Lisa A
LA
Department of Nutritional Sciences, University of Toronto, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada.
Sherwood
Kelly L
KL
Pawlosky
Robert
R
Ito
Shinya
S
O'Connor
Deborah L
DL
D000328:Adult; D001682:Biological Availability; D001774:Blood Chemical Analysis; D019587:Dietary Supplements; D004311:Double-Blind Method; D004912:Erythrocytes / Q000737:chemistry*; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage / Q000097:blood* / Q000378:metabolism; D005494:Folic Acid Deficiency / Q000517:prevention & control*; D006801:Humans; D007774:Lactation / Q000097:blood* / Q000378:metabolism; D010919:Placebos; D011247:Pregnancy; D013763:Tetrahydrofolates / Q000008:administration & dosage* / Q000097:blood / Q000378:metabolism; D016896:Treatment Outcome; D014803:Vitamin B Complex / Q000008:administration & dosage* / Q000097:blood / Q000378:metabolism
D010919:Placebos; D013763:Tetrahydrofolates; D014803:Vitamin B Complex; D005492:Folic Acid; C005984:5-methyltetrahydrofolate