One small drink a day increases breast cancer risk, study shows

Drinking even one small alcoholic beverage a day can increase a person's breast cancer risk, according to a new report. Consuming 10 grams of alcohol a day or about the size of a small glass of wine or beer, can increase breast cancer risk by 5% in premenopausal
women and 9% in postmenopausal women, according to the report by the American Institute for Cancer Research (AICR) and the World Cancer Research Fund.

Alcohol is a known carcinogen, said Alice Bender, head of nutrition programs at AICR. It can damage DNA, allowing cancer cells to develop, and increases circulating estrogen, which can increase risk for certain cancers.

The outcome that just a small amount of alcohol increases breast cancer risk was "surprising," said the study's lead author Anne McTiernan.

"Some other individual studies had suggested that risk only started with 2 drinks per day or more," she said. "But this meta-analysis, where we combined results from many large cohort studies, was definitive."

McTiernan told CBS the study isn’t meant to discourage women from drinking at all, but to remind them to stick to the government’s dietary guidelines and consume no more than one drink a day on average. 

“We're not saying anything other than small amounts do increase the risk for breast cancer,” she said.

But there's good news. Researchers also discovered a more vigorous exercise routine is proven to lower your risk of breast cancer by 17% in premenopausal women and 10% in post-menopausal women.

The study found vigorous activity further lowers breast cancer risk compared to moderate exercise. Physically active people are more likely to maintain a healthy weight throughout their lifetime, Bender explained, and obesity increases the risk for many cancers.

She said certain types of body fats release hormones and compounds that can increase the risk for cancer.

Using the "talk test" is a good way to differentiate between moderate and vigorous exericse, Bender explained. During moderate exercise, you can carry on a conversation. In vigorous exercise, breathing becomes more labored making a conversation difficult.

Bender and McTiernan cautioned that cutting back on the booze or boosting your exercise regimen aren't sure-fire ways to avoid breast cancer.

"It's not a guarantee," said McTiernan. "I think of it like a seatbelt. It's not a surety that you'll be saved from injury in a car crash, but using a seat belt reduces your risk."

In the United States, breast cancer is the most common cancer in women, according to the Centers for Disease and Control.  Researchers are still trying to pinpoint how alcohol influences breast cancer risk, and some research suggests it increases the hormone estrogen. 

But despite the small risk of breast cancer, studies have also found that small amounts of alcohol each day can reduce the risk of heart disease. 

Source: usatoday.com