According to a report from the World Cancer Research Fund, half a glass of wine or a small beer a day can increase the risk of breast cancer – further bringing about the link between alcohol consumption in women and an increased risk of the deadly ailment.Sipping an average of 10 grams of alcohol a day – equivalent to a small glass of wine, an 8-ounce beer or 1 ounce of hard liquor – is associated with a 5% increased breast cancer risk in premenopausal women and 9% increase in postmenopausal women, said Dr. Anne McTiernan, a lead author of the new report and a cancer prevention researcher at the Fred Hutchinson Cancer Research Center in Seattle.
“I was most surprised by the alcohol result, that risk increases at just one drink a day, on average,” McTiernan said, adding that “the increase with one drink a day was small … but the risk goes up from there. So that’s why AICR recommends no more than one alcohol drink a day for women to reduce risk for cancer.”
Breast cancer is by far the most common cancer in women in the UK with one in eight women developing the disease during their lifetime.
However, the scientists disclosed that they can’t explain why the cancer occurs in some people and not in others.
They said there are numerous causes and lots of factors to take into account, including lifestyle, hormone levels and other medical conditions.
In the new report, researchers analyzed 119 observational studies on breast cancer risk from around the world. Those studies included 12 million women total and more than 260,000 cases of breast cancer.
Although breast cancer can occur in men, it is rare — accounting for less than 1% of cancer incidence — and such cases were not included in the report.
When analyzing associations specifically between breast cancer risk and alcohol use, “the premenopausal analysis included 10 large cohort studies in which over 4,000 women developed breast cancer,” McTiernan said. “The postmenopausal analysis included 22 large cohort studies in which over 35,000 women developed breast cancer.”
Speaking also on the development, Chin-Yo Lin, a researcher at the University of Houston’s Center for Nuclear Receptors and Cell Signaling, said there are a number of possible explanations for the link between alcohol consumption and breast cancer risk.
For instance, “in exposed tissues, alcohol is converted into acetaldehyde, a chemical that can cause mutations in DNA, which can potentially lead to cancer,” said Lin who was not involved in the new report.
“Alcohol consumption is also associated with elevated levels of the female sex hormone estrogen. Excessive cumulative exposure to estrogen is a major risk factor in breast cancer,” he said. “A number of studies have shown that alcohol can enhance the actions of estrogen in breast cancer cells.”
When it comes to exercise, the report found that doing more vigorous exercise, like cycling or running, cut the risk of post-menopausal breast cancer by 10% compared to the least active women.
Breastfeeding was also found to lower the risk of the disease before and after the menopause.
And there was limited evidence that eating more leafy vegetables, such as cabbage, spinach and kale, decreased the risk of a less common kind of breast cancer.
