WEDNESDAY, July 18, 2001 (HealthDayNews) -- Watch your alcohol intake, take your vitamins and worry less about breast cancer.
A study of nearly 100,000 woman found that women who drink once in a while and meet their daily requirement of the B vitamin folic acid reduce their alcohol-related risk of breast cancer to levels of women who don't drink at all.
"My belief is that folate [folic acid] is contributing as an excellent component to DNA repair, hence it seems to be undoing the damage caused by alcohol," says study author Thomas Sellers, a cancer epidemiologist at the Mayo Clinic in Rochester, Minn., where the data analysis took place.
Doctors have long known that the risk of post-menopausal breast cancer increases with alcohol consumption because "alcohol is metabolized to acetaldehyde, a known carcinogen," says Sellers.
However, when intake of folic acid is adequate -- the recommended 400 micrograms a day will do -- and the intake of alcohol amounts to about one drink a week, the body's ability to repair damage caused by acetaldehyde is enhanced, Sellers says.
Dr. Paolo Toniolo, professor of epidemiology at New York University Medical Center and a cancer researcher, says, "There is growing evidence that there is an interaction between alcohol intake and folic acid, and for those who drink in moderation -- less than 4 grams of alcohol a day, like the women in the study -- folic acid may reverse some negative actions, in this case at the level of breast cancer."
But the catch word is "moderate."
"For those who drink too much, the benefits of folic acid are lost," even if you increase your folic acid intake substantially, says Toniolo.
"The relationship between folic acid and alcohol is exponential. So, if alcohol consumption goes above the level of moderate intake, it is almost impossible to consume enough folic acid to counter the damage," Toniolo says.
The study was based on data from the Iowa Women's Health Study, which began in 1986 with a 16-page questionnaire mailed to some 100,000 women, ages 55 to 69. The questions addressed a variety of dietary and lifestyle issues, including alcohol consumption and vitamin intake.
After a 12 year follow-up, 1,586 of the women had developed breast cancer.
The Mayo Clinic researchers analyzed the data looking for links between B vitamins, alcohol intake and cancer rates.
"We converted alcohol intake into grams per day," Sellers says, and then grouped the women into categories: never drinkers, drinkers of less than 4 grams of alcohol a day and drinkers of more than 4 grams a day. (One ounce equals 28 grams, and a 12-ounce can of beer or a 4-ounce glass of wine usually includes one ounce of alchol.)
These groups were further divided according to B vitamin intake and then folic acid intake. A statistical analysis compared the women in all groups.
Sellers says the results proved what doctors have suspected: Adequate folic acid intake can reduce the alcohol-related risks of breast cancer, but only in women who consume about one drink per week.
The study also showed that even moderate drinkers have some breast cancer risks when folic acid intake is low.
"At low folic-acid intake, both high and low levels of alcohol consumption were associated with increased risk, and those with higher [alcohol] intakes had higher risks," says Sellers.
The findings appear in the July issue of the journal Epidemiology.
What To Do
The best way to ensure a high level of folic acid is to eat a diet rich in fruits, vegetables and whole grains, experts say. Folic acid supplements also can provide the protection you need.
"All you need is 400 micrograms of folic acid daily, and for those who are not eating a healthy diet, supplementation is the way to go," Toniolo says.
And while the studies have focused on post-menopausal women, Sellers says it's never too early -- or too late -- to reap the benefits of folic acid.
"We tell smokers that it's never too late to quit, and it seems prudent to offer the same kind of never-too-late recommendation regarding folic acid intake, regardless of age or menopausal status," Sellers says.
To learn more about foods that contain high levels of folic acid, visit the U.S. Food and Drug Administration.
To read more about the links between diet and breast cancer, visit the
Cornell University Program on Breast Cancer and Environmental Risk Factors.
