Folic Acid, B12 Combo Reduces Risk of Vascular Disease

Folic Acid, B12 Combo Reduces Risk of Vascular Disease

DUBLIN, Ireland--Joe McPartlin, Ph.D., and colleagues fromSt. James's Hospital discovered that folic acid in combination with vitamin B12lowers plasma total homocysteine (a risk factor for vascular disease) moreeffectively than folic acid alone. McPartlin and his colleagues published astudy in the Jan. 19 issue of The Lancet (359: 227-28, 2002) (www.thelancet.com)as basis for their suggestion that the proposed grain fortification program forthe United Kingdom be amended to include vitamin B12 in addition to folic acid.

The researchers investigated the correlation between homocysteine levels andfolate and vitamin B12 status before and after folic acid supplementation. The30 male and 23 female participants were instructed to avoid supplements andfoods fortified with folic acid and B vitamins before and during the 36-weekstudy. For 26 weeks, the men were given folic acid at increasing doses, from 100mcg/d to 400 mcg/d, while the women received 500 mcg/d of folic acid. Thesupplementation period was followed by a 10-week washout period.

In both groups, homocysteine levels were found to be directly related toserum folate concentrations, with more positive levels occurring with folic acidsupplementation. However, as the dose of folic acid increased, homocysteinelevels became more dependent on B12 for proper metabolism. Researchers suggestedthat while homocysteine concentration depends on folate status, supplementingwith folic acid shifts the body's dependence to vitamin B12 for regulatinghomocysteine levels; however, this dependence reverts when folic acidsupplementation ceases.

Owing to this finding, researchers concluded that if the mandatory folic acidgrain fortification were initiated, this would cause the UK population to becomedependent on vitamin B12 for maintaining normal homocysteine metabolism. Anotherside effect of folic acid supplementation is the masking of vitamin B12deficiency. Researchers recommended that greater cardio-protective benefitswould be had if the mandatory grain fortification program were to include folicacid and vitamin B12.

Phil Harvey, Ph.D., director of science and quality for the NationalNutritional Foods Association, noted that the United States' grain fortificationprogram has been dramatically successful in reducing the numbers of neural tubedefects in the country. However, he concurred with the study's authors thatadding vitamin B12 would only enhance the health benefits. "Folate is veryimportant directly, but it works hand-in-hand with vitamin B12, as well as withvitamin B6 and other nutrients. ... Adding B12 would be a goodcombination."