Consuming as little as one drink a day or less may raise a woman's risk of developing breast cancer, according to a new study published this week.
European researchers analyzed data from more than 100 studies that looked at the relationship between alcohol consumption and breast cancer and found that having up to one drink per day raised women's risk for the disease by 4 percent. Three or more drinks per day increased risk by 40 to 50 percent.
"Women should not exceed one drink [per] day, and women at elevated risk for breast cancer should avoid alcohol or consume alcohol occasionally only," concluded the authors, led by Helmut K. Seitz of the University of Heidelberg in Heidelberg, Germany.
Previous research has also found a link between light alcohol consumption and elevated breast cancer risk. A study published in November found that as few as three to six drinks per week raised risk by 15 percent.
Some experts said the findings support current recommendations for women to drink in moderation in order to minimize their risk of breast cancer as well as other health conditions. They added that while it's important to avoid excessive drinking, women should also consider alcohol as one of numerous factors that can play a role in the development of cancer and other illnesses.
"The American Cancer Society guidelines say that for women who don't drink, there is no reason to start drinking, and not just to prevent breast cancer. It can even prevent heart disease," said Susan Gapstur, vice president of epidemiology research at the American Cancer Society. "For women who do drink, they should limit their consumption to no more than one drink per day. This study underscores that these guidelines are reasonable."
Dr. Stefan Gluck, a professor at the University of Miami Sylvester Cancer Center, argued that although excessive drinking should absolutely be avoided, there is nothing wrong with having one drink a day. The 4 percent increased risk among women who had one drink a day is a very small increase, he said, and other factors play a bigger role.
"There are many other things that are more important," he said. "If you look at the American Association for Cancer Research report from last year, 30 percent of all cancer deaths were attributable to smoking and another 30 percent were attributable to obesity."
That same report found alcohol played a role in about 3 percent of cancer deaths.
Gapstur added that even though the study found light drinking elevated risk only moderately, breast cancer is a very common cancer, meaning 4 percent can add up to a lot of women.
Other studies have found that moderate alcohol intake can protect against heart disease.
"A large number of observational studies have consistently demonstrated a reduction in coronary heart disease with moderate alcohol consumption. Prohibiting alcohol consumption would deny a potentially sizable health benefit to people who would otherwise choose to drink," the American Heart Association says on its website.
The American Heart Association recommends that women have no more than one drink per day.
While she stressed that a drink a day should be the maximum, Gapstur added that women should get an overall picture of their individual risk for different illnesses to get a better sense of what lifestyle changes to make to improve overall health.
"The message continues to be know your health, maintain your health, see your doctor regularly and understand your risk for cancer and heart disease," she said.