The short-term bioavailabilities of [6S]-5-methyltetrahydrofolate and folic acid are equivalent in men.
The natural folate derivative, 5-methyltetrahydrofolate ([6S]-5-MTHF), could be an option for supplementation and fortification but its bioavailability remains unclear. This study compared the bioavailability of [6S]-5-MTHF with that of folic acid (FA) by measuring plasma folate responses after a single ingestion of equivalent doses of the two folate forms. In a double-blind, crossover study, 13 men (presaturated with FA) received in random order each of the following treatments administered orally at 1-wk intervals: 1) placebo capsule; 2) 500 micro g FA capsule; and 3) 500 micro g [6S]-5-MTHF capsule. Plasma total folate concentrations were measured before and up to 10 h after each treatment (n = 10 samples per treatment). Plasma folate concentrations increased significantly (compared with baseline) from 0.5 to 5 h after both folate treatments. The maximum plasma folate response did not differ between the two treatments (mean +/- SEM, 33.4 +/- 3.9 vs. 31.8 +/- 3.9 nmol/L, P = 0.7, for FA and [6S]-5-MTHF, respectively) and typically occurred in individuals between 0.5 and 3 h postprandially. The area under the plasma folate response curve was significantly greater after both folate treatments compared with placebo, and the response did not differ between the treatments. These results indicate that the short-term bioavailabilities of [6S]-5-MTHF and FA are equivalent. Supplementation with the natural folate derivative could have all the beneficial effects associated with FA, but without the potential disadvantage of masking the anemia of vitamin B-12 deficiency.
Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, Northern Ireland BT52 1SA. K.Pentieva@ulster.ac.uk
Kristina
K
Pentieva
Helene
H
McNulty
Rebecca
R
Reichert
Mary
M
Ward
J J
JJ
Strain
Derek J
DJ
McKillop
Joseph M
JM
McPartlin
Edel
E
Connolly
Anne
A
Molloy
Klaus
K
Krämer
John M
JM
Scott
D000328:Adult; D001682:Biological Availability; D018592:Cross-Over Studies; D004032:Diet; D004311:Double-Blind Method; D002149:Energy Intake; D005492:Folic Acid / Q000097:blood*; D005838:Genotype; D006710:Homocysteine / Q000097:blood; D006801:Humans; D007700:Kinetics; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics; D013763:Tetrahydrofolates / Q000097:blood*; D013997:Time Factors; D014805:Vitamin B 12 / Q000097:blood
D013763:Tetrahydrofolates; D006710:Homocysteine; C013123:5,10-methylenetetrahydrofolic acid; D005492:Folic Acid; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D014805:Vitamin B 12