title: Effects of folic acid and combinations of folic acid and vitamin B-12 on plasma homocysteine concentrations in healthy, young women.
abstract: BACKGROUND
  Elevated plasma homocysteine concentrations are considered to be a risk factor for vascular disease and fetal malformations such as neural tube defects. Recent studies have shown that plasma homocysteine can be lowered by folic acid in amounts corresponding to 1-2 times the recommended dietary allowance. Preliminary evidence indicates that vitamin B-12 may be beneficial when included in supplements or in a food-fortification regimen together with folic acid.
  
  
  OBJECTIVE
  We aimed to compare the homocysteine-lowering potential of a folic acid supplement with that of 2 supplements containing different doses of vitamin B-12 in addition to folic acid.
  
  
  METHODS
  Female volunteers of childbearing age (n = 150) received a placebo for 4 wk followed by a 4-wk treatment with either 400 microg folic acid, 400 microg folic acid + 6 microg vitamin B-12, or 400 microg folic acid + 400 microg vitamin B-12.
  
  
  RESULTS
  Significant reductions (P < 0.001) in plasma homocysteine were observed in all groups receiving vitamin treatment. The effect observed with the combination of folic acid + 400 microg vitamin B-12 (total homocysteine, -18%) was significantly larger than that with a supplement containing folic acid alone (total homocysteine, -11%) (P < 0.05). Folic acid in combination with a low vitamin B-12 dose (6 microg) affected homocysteine as well (-15%).
  
  
  CONCLUSIONS
  These results suggest that the addition of vitamin B-12 to folic acid supplements or enriched foods maximizes the reduction of homocysteine and may thus increase the benefits of the proposed measures in the prevention of vascular disease and neural tube defects.
authors.affiliation: Institute of Nutritional Science, Department of Pathophysiology of Human Nutrition, University of Bonn, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Brönstrup
authors.forename: M
authors.initials: M
authors.lastname: Hages
authors.forename: R
authors.initials: R
authors.lastname: Prinz-Langenohl
authors.forename: K
authors.initials: K
authors.lastname: Pietrzik
mesh_terms: D000328:Adult; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D006710:Homocysteine / Q000097:blood* / Q000187:drug effects; D006801:Humans; D014805:Vitamin B 12 / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D004338:Drug Combinations; D006710:Homocysteine; D005492:Folic Acid; D014805:Vitamin B 12