A new report claims that having a drink every day increases women’s risk of breast cancer. The report, conducted by the World Cancer Research Fund and the American Institute for Cancer Research, revealed how much of a risk daily drinking poses for premenopausal and postmenopausal women.
Drinking an average of 10 grammes of alcohol a day is associated with a 5 or 9 percent increased breast cancer risk.
Drinking a glass of wine or a small beer daily increases breast cancer risk by 5 percent
The report noted that 10 grammes of alcohol, which are equivalent to a small glass of wine, 1 ounce of hard liquor or an 8-ounce beer, increased breast cancer risk by 5 percent in premenopausal women and by 9 percent in postmenopausal women.
“I was most surprised by the alcohol result, that risk increases at just one drink a day, on average,” said. Dr. Anne McTiernan, lead author of the report and cancer prevention researcher at the Fred Hutchinson Cancer Research Center in Seattle, according to CNN. “The increase with one drink a day was small… but the risk goes up from there.”
McTiernan noted that’s why the AICR recommends no more than one alcohol drink a day for women, to reduce the risk of cancer. Breast cancer is the top cancer in women in the world, according to the World Health Organization.
In the United Kingdom and the United States, around 12 percent of women will develop breast cancer at some point in their lives, according to the National Cancer Institute and the organisation Cancer Research UK.
In the new report, researchers looked at 119 observational studies focused on breast cancer from around the world, analysing data from 12 million women total and around 260,000 cases of breast cancer.
Breast cancer can affect men too, although it is rare, as it accounts for less than 1 percent of cancer incidence, and those cases were not included in the report.
According to McTiernan, the premenopausal analysis included ten large cohort studies in which 4,000 women developed breast cancer, and the postmenopausal analysis included 22 large cohort studies in which 35,000 developed cancer.
Obesity can increase -or decrease- breast cancer risks
According to the report, over 1.7 million new breast cancer cases were recorded globally in 2012, accounting for 25 percent of all new cases of cancer in women. Breast cancer is the fifth most common cause of death from cancer in women.
Breast cancer risks for women doubles each decade until the menopause, after which the increase slows down. However, it is more common for women to develop the cancer after the menopause, and researchers noted that the highest incidence is in North America and the lowest incidence is in Eastern Asia and Middle Africa. For example, in 2012 the rate of new cases of breast cancer in North America was more than double that in Africa.
The report also found other causes linking breast cancer to pre or postmenopausal women in the world. The researchers found that undertaking a vigorous physical activity, being overweight or obese between the ages of 18 and 30 years, being overweight or obese in adulthood before the menopause or breastfeeding, all contributed to a decreased risk of breast cancer for pre and postmenopausal women.
On the other hand, the risks increase for premenopausal women if they develop factors leading to greater linear growth -marked by adult attained height- or factors that lead to greater birthweight, or its consequences. Risks also increase in postmenopausal women if they gain too much weight during adulthood, or if they are overweight or obese throughout their entire adulthood.
Limiting alcohol and healthy diets can prevent breast cancer in women
The researchers also found limited evidence suggesting that diets high in calcium and foods containing carotenoids, like sweet potatoes, carrots or dark green leafy vegetables, might be tied to a decreased risk of pre and postmenopausal breast cancer.
“Eating a diet that’s high in fruit and vegetables that keeps your weight in a good range, exercising regularly, limiting alcohol, those are all things that we know are good for general health,” said Dr. Jennifer Ligibel, a breast oncologist and professor at Harvard Medical School, who was not involved in the report, according to CNN. ” This report really strengthens that those may also be an important part of limiting your risk of breast cancer.”
According to McTiernan, there are things that women can do to reduce their risk for breast cancer, and she noted it’s never too late to start. McTiernan recommends women to maintain weight at a normal level, to exercise at least 150 minutes per week at a moderate intensity (like walking), limiting alcohol to one drink per day, on average, and eating a plant-based diet, high in vegetables and fruits and low in refined carbohydrates and sugars.