Folic Acid and Vitamin B-12 May Help Prevent Heart Disease
Dec. 11, 2000 -- High levels of the amino acid homocysteine
have been shown to cause harm by increasing clot formation in the blood vessels
in the heart. Recent evidence suggests that vitamins B-12 and folic acid may
help prevent heart disease by lowering the body's levels of homocysteine. But
until clinical trials are completed in about four years, the jury is still out
about not only the damaging effects of the amino acid but also the vitamins'
potential benefit in preventing heart disease.
High levels of the harmful amino acid homocysteine may account
for up to 10% of deaths from heart disease in men and 6% in women. But
"may" is the operative word, and until the verdict is in, the authors
of a study published in this week's Archives of Internal Medicine say
using folic acid and vitamin B-12 to treat middle-aged people with high levels
of homocysteine "may be a prudent option."
The researchers, from the University of Michigan in Ann Arbor,
calculated whether it makes more sense to give multivitamins to everyone, or
just to people with elevated homocysteine levels. They looked at patients
taking 400 mcg of folic acid and 500 mcg of vitamin B-12 daily, and found that
it would be most cost-effective if the supplements go to those whose blood
tests show elevated levels of homocysteine.
Of course, those who are not necessarily "at-risk" can
also benefit from the vitamins. Study author Brahmajee Nallamothu, MD, tells
WebMD consumers should try to get enough folic acid and vitamin B-12 through
their diets. Nallamothu is a fellow in the division of cardiovascular diseases
at the University of Michigan Health System.
Clinical nutrition consultant Linda Rodriguez says the best
food sources of folic acid are citrus fruits, tomatoes, vegetables, whole grain
and fortified grain products, beans and lentils. Major sources of B-12 include
meat, poultry, fish and dairy products. Rodriguez also recommends vitamin B-6,
B-12 and folic acid supplements because of their probable effect on
homocysteine levels and cardiac disease. Rodriguez is in private practice in
But Robert H. Eckel, MD, tells WebMD, "we don't know enough
yet" to recommend these vitamin supplements to prevent heart disease. He
notes that in some people elevated homocysteine levels may be a sign of other
significant health problem such as kidney disease.
"We think a healthy diet, including fruits, vegetables,
whole grains, and fish, is really where people should be. In the opinion of the
American Heart Association, vitamin supplements should not be encouraged until
they are proven beneficial," he says. Eckel is the chair of the American
Heart Association committee on nutrition and a professor of medicine and
physiology at the University of Colorado Health Sciences Center in Denver.
Like Eckel, Charles Hennekens, MD, a visiting professor of
medicine, epidemiology, and public health at the University of Miami (Fla.)
School of Medicine, emphasizes that we are sure lifestyle changes can be
effective in reducing heart disease risk, but the use of vitamin supplements is
still under consideration. "We know people with higher homocysteine levels
tend to have higher risk of heart disease. We also know if you give people
folic acid it reduces homocysteine levels. Observational studies suggest that
people who are taking folic acid have lower levels of heart disease but we
don't have the evidence. Studies are needed to definitely show whether folic
acid supplements do in fact lower heart disease risk."
Meanwhile, he also strongly recommends eating a diet rich in
fruits, vegetables, and whole grains.