The news media have been filled with reactions to the U.S. Surgeon General’s recent pronouncement that alcohol was a major cancer risk, and that alcoholic beverages should carry a cancer warning label like that on cigarette packages. (Ireland currently requires such warning labels.)
The World Health Organizations estimates that about 4% of cancers worldwide are alcohol-related.
The long-touted heart protective effects of alcohol have been questioned.
What should you believe?
First, some definitions. A “standard” drink is defined as 5 ounces of wine, 12 of beer and 1.5 ounces of liquor.
Women metabolize alcohol differently than men, and so have higher blood levels than men from the same amount consumed.
Almost all studies of the effects of alcohol on health are flawed.
First, they depend on self-reported consumption. Since many, if not most, people know that heavy drinking is not good, there is a strong tendency to under-report what you drink.
Second, they are observational: groups are followed and their health outcomes studied. We know that this type of study is prone to bias. People who drink alcohol may have many other habits that non-drinkers do not share, such as smoking.
Alcohol consumption has been linked to higher incidences of head and neck cancer, liver cancer, colorectal cancer, esophageal cancer and breast cancer.
Even the most toxic of substances only cause harm at threshold doses, and for most toxins, the more, the worse. Consistent with this, the National Academy of Medicine estimated that 2 drinks/week would shorten your life by less than a week, 7 drinks/week would shorten your life by 2.5 months while 5 drinks/day would shorten it by over two years.
A recent study from Spain shed fascinating light on wine and the heart. Rather than ask subjects how much they drank, they took urine samples and measured metabolites of wine to objectively estimate how much they drank. They found that light-to-moderate drinkers (from ½ to 1 glass/day) had 50% fewer cardiac events over 6 years of follow-up. This protective effect disappeared in those who drank more than 1 glass/day.
My take-aways:
If you do not drink, there is no reason to start. There are no net health benefits to drinking.
If you drink heavily (more than 2 drinks/day for men, 1/day for women), please cut down. You are harming yourself.
If you enjoy a glass of wine a few times a week, relax. The slight increased cancer risk is probably balanced by less heart disease.
The Greeks had it right: all things in moderation.
Edward Hoffer MD is Associate Professor of Medicine, part-time, at Harvard.
What Does The Doctor Say?
By Dr. Edward Hoffer