Long-term excessive alcohol consumption is clearly deadly – alcoholic liver disease accounts for nearly 5,000 deaths in the UK every year. However, drinking red wine in controlled amounts has proven to be beneficial for the heart; it showed a 14% to 25% reduction in heart disease in moderate drinkers compared with those who had never consumed alcohol. One of the challenges here is the definition of moderate. The effect of alcohol as a beneficiary was noticed in those regularly drinking between 2.5g and 14.9g of alcohol (one small glass of wine contains approximately 12g). The lead researcher at the time, William Ghali, told the BBC; “Our extensive review shows that drinking one or one to two drinks would be favourable”.
A new study, published in the latest issue of the Journal of the American Medical Association, shows that women who routinely have even small amounts of alcohol (which was previously declared “safe” or even beneficial), as few as three drinks a week (only a glass more than Ghali’s “favourable” amount), have an elevated risk of breast cancer.
The research looked at the habits of more than 100,000 women over 28 years. It conclusively linked alcohol consumption of any kind — whether it be beer, wine or spirits — to an increased risk of breast cancer. The study suggested that consuming between 3 and 6 small glasses of wine a week (5-10 grams of alcohol a day) was linked to a 15% increase in the risk of suffering from breast cancer. Roughly 7,700 women enrolled developed breast cancer over the period of this study. Additionally, the effects were cumulative; with each 10 gram increase of alcohol consumption per day, the risk climbed up a further 10%.
While such an increase may sound alarming, experts caution that it translates into only a small risk for the average woman. For example, a typical 50 year-old woman has a five-year breast cancer risk of about 3%. Hence a 15% increase would increase that risk only to 3.45%. In an accompanying editorial Dr. Steven Narod of the Women’s College Research Institute in Toronto pointed out that based on the findings, women who consumed two or more drinks a day would see their 10-year risk of breast cancer climb to 4.1% from 2.8%. And for women who had one drink a day, it would rise to 3.5% from 2.8%.
Further statistics show that, for women who do not consume alcohol, 281 breast cancers per 100,000 women per year were found. That increased to 333 cancers for people drinking between 3 and 6 glasses of wine per week. There was a much greater surge, to 413, for those consuming more than 19 glasses.
One of the researchers, Dr Wendy Chen said; “Although the exact mechanism for the association between alcohol consumption and breast cancer is not known, one probable explanation would involve alcohol’s effects on circulating oestrogen levels”. A large number of cancers, in both men and women, are identified as being hormonally responsive and in a great many of these cases the prime culprit is oestrogen. Oestrogen is not a single hormone, but a family of hormones with variable chemical strengths. One, Oestradiol, is particularly aggressive, it can settle on cellular membranes of healthy cells and wreak havoc inside the cell; increasing sodium levels, reducing potassium, oxygen and energy levels, and can also cause genetic change. Moreover, it can cause stem cells to remain in their rapidly dividing “elementary” state (which are found in some brain tumours).
Alcohol has also proven to interfere with oestrogen levels in teenagers who suffer from polycystic ovary syndrome (or polycystic ovarian disease). On cutting down their alcohol intake, teenagers suffering from PCOD have often eliminated the disease. In fact, one of the prime reasons it is so rampant in teenagers is because of their alcohol intake. A healthy lifestyle is not a guarantee against cancer, but it definitely stacks the odds in ones’ favour.
Doctor Susan Love, a clinical professor at the David Geffen School of Medicine at the University of California, Los Angeles, said the question for many women remained; is cutting back on alcohol, to decrease the risk of breast cancer, worth losing out on the reduction in heart disease that comes with moderate drinking? The rise in cancer risk from 3 to 6 drinks a week was modest. For some women, this may outweigh the heart-healthy benefits of drinking. But of course, women should consider family history of heart disease and cancer as well as their use of hormone therapies (such as oestrogen).
“If you do drink, you have to weigh the risks and benefits,” said Doctor Love. “But obviously if you don’t drink and you’re worried about breast cancer, don’t start.”