Comparison of the effect of low-dose supplementation with L-5-methyltetrahydrofolate or folic acid on plasma homocysteine: a randomized placebo-controlled study.
BACKGROUND
Food fortification with folic acid has been introduced in several countries for the prevention of neural tube defects. Fortification has lowered total homocysteine (tHcy) concentrations in the US population, a consequence that may have health benefits. However, folic acid fortification could mask vitamin B-12 deficiency. Synthetic L-5-methyltetrahydrofolate (L-MTHF) may be more appropriate than folic acid as a fortificant because it is unlikely to mask the hematologic indicators of vitamin B-12 deficiency.


OBJECTIVE
The objective of the study was to compare the effectiveness of 100 micro g folic acid/d with that of equimolar L-MTHF in lowering tHcy in healthy volunteers.


METHODS
The study was designed as a 24-wk, randomized, placebo-controlled intervention. Free-living healthy volunteers (n = 167) were randomly assigned to receive a daily supplement containing folic acid (100 microg), L-MTHF (113 microg), or placebo. Blood collected at baseline and at 8, 16, and 24 wk was analyzed for tHcy, plasma folate, and red blood cell folate (RCF) concentrations.


RESULTS
At 24 wk, after adjustment for baseline values, mean (95% CI) tHcy was 14.6% (9.3, 19.5%) and 9.3% (3.7, 14.6%) lower, mean plasma folate was 34% (14, 56%) and 52% (30, 78%) higher, and mean RCF was 23% (12, 35%) and 31% (19, 44%) higher in the L-MTHF and folic acid groups, respectively, than in the placebo group. L-MTHF was more effective than was folic acid in lowering tHcy (P < 0.05). At 24 wk, the increases in plasma folate and RCF concentrations did not differ significantly between the 2 supplemented groups.


CONCLUSIONS
Low-dose L-MTHF is at least as effective as is folic acid in reducing tHcy concentrations in healthy persons.
Venn
Bernard J
BJ
Department of Human Nutrition, University of Otago, Dunedin, New Zealand.
Green
Timothy J
TJ
Moser
Rudolf
R
Mann
Jim I
JI
D000328:Adult; D019587:Dietary Supplements; D004311:Double-Blind Method; D004912:Erythrocytes / Q000737:chemistry; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000097:blood; D005527:Food, Fortified; D006710:Homocysteine / Q000097:blood* / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009436:Neural Tube Defects / Q000517:prevention & control; D010919:Placebos; D013763:Tetrahydrofolates / Q000008:administration & dosage*; D016896:Treatment Outcome; D014806:Vitamin B 12 Deficiency / Q000175:diagnosis
D010919:Placebos; D013763:Tetrahydrofolates; D006710:Homocysteine; D005492:Folic Acid; C005984:5-methyltetrahydrofolate