BONN, GERMANY. There is increasing evidence that high blood levels of the amino acid homocysteine increases the risk of vascular disease, coronary heart disease, neural tube defects, and Alzheimer's disease. Folic acid supplementation is known to lower homocysteine levels and laws have recently been passed in the United States mandating folic acid fortification of bread and cereal. Now researchers at the University of Bonn report that folic acid's homocysteine lowering capacity can be markedly increased by also supplementing with vitamin B-12 (cobalamin). Their study involved 150 young, healthy women (average age of 24 years) who after a four-week washout period were randomized into three groups. Group 1 received a daily supplement of 400 micrograms of folic acid, group 2 received 400 micrograms/day of folic acid and 6 micrograms/day of vitamin-B12, and group 3 received 400 micrograms/day of folic acid and 400 micrograms/day of vitamin B-12. After four weeks the average concentration of plasma homocysteine had dropped by 11 per cent in group 1, 15 per cent in group 2, and 18 per cent in group 3. The researchers noted that study participants with high initial homocysteine concentrations benefitted more from supplementation than did women with lower initial homocysteine levels. It was also noted that vitamin B-12 levels increased significantly over the four- week period in the women whose supplements included vitamin B-12. This provides further proof that oral vitamin B-12 is indeed adequately absorbed. The researchers conclude that the benefits of folate supplementation can be markedly enhanced by the addition of vitamin B-12. They point out that vitamin B-12 deficiency is widespread especially among the elderly. The addition of vitamin B-12 to folic acid supplements also prevents the possibility that supplementation with just folic acid could mask pernicious anemia resulting from a vitamin B-12 deficiency which in turn may lead to irreversible nerve damage.
Bronstrup, Anja, et al. Effects of folic acid and combinations of folic acid and vitamin B-12 on plasma homocysteine concentrations in healthy, young women. American Journal of Clinical Nutrition, Vol. 68, November 1998, pp. 1104- 10