Monday, February 24, 2014
Does Beer Cause Cancer?
by Carol A. Westbrook
I have been taken to task by several of my readers for promoting beer drinking. "How can you, a cancer doctor, advocate drinking beer, " I was asked, "when it is KNOWN to cause cancer?" I realized that it was time to set the facts straight. Is moderate beer drinking good for your health, as I have always maintained, or does it cause cancer?
Recently there has been some discussion in the popular press about studies showing a possible link between alcohol and cancer. As a matter of fact, reports linking foods to cancer causation (or prevention) are relatively common. I generally ignore these press releases because they generate a lot of hype but are usually based on single studies that, on follow-up, turn out to have flaws or cannot be confirmed; the negative follow-up study rarely receives any publicity. Moreover, there are often other studies published at other times showing completely contradictory results; for example, that red wine both prevents and causes cancer.
Furthermore, there is a great deal of self-righteousness about certain foods, and this attitude can cloud objectivity and lead to bias in interpreting the results; often these feelings have strong political implications as well. Some politically charged dietary issues include: vegetarianism; genetically modified crops; artificial sweeteners; sugared soft drinks. Alcohol fits right into this category--remember, we are the country that adopted prohibition for 13 years. There is no doubt the United States has significant public health issues related to alcohol use, including alcohol-related auto accidents, underage drinking, and alcoholism, and the consequent problems of unemployment, cirrhosis of the liver, brain and neurologic problems, and fetal alcohol syndrome. Wouldn't it be great if the government could mandate a label on every beer can stating, "consumption of alcohol can cause cancer and should be avoided"? Wouldn't that be a wonderful "I told you so!" for the alcohol nay-sayers?
Before going further, I will acknowledge that are alcohol-related cancers. As a specialist I am well aware that cancers of the head and neck area, the larynx (voice box) and the esophagus are frequently seen in heavy drinkers, almost always in association with cigarette smoking. Liver cancer is seen primarily in people with cirrhosis--also a result of heavy drinking. In both instances, the more alcohol that is consumed, the greater the risk of developing one of these cancers--and I have rarely seen these cancers in non-smokers or non-drinkers. But assuming that my readers are not alcoholics, the question that they are really asking is whether or not they are going to get cancer from low to moderate beer drinking.
So what, then, are the facts? Does beer cause cancer? This is a much more difficult question to answer than most people realize, and can easily be the subject of years of study for a PhD dissertation (and probably has been). Researchers will be quick to admit how difficult it is to do scientifically rigorous studies on the health effects of individual dietary components. You can't just take a group of thirty year-olds, split them into two groups, give beer to one group and make the other abstain, watch them for 20 years and see who gets more cancer. So we have to rely on population studies, estimating alcohol consumption based on purchasing statistics, self-reporting of drinking (which is often unreliable), surveys, and death certificates for cancer. Incidentally, beer is not considered separately from other alcoholic beverages in any of these studies.
For example, an interesting study by Holahan and colleagues, published in 2010 in the journal Alcoholism: Clinical and Experimental Research, followed 1,824 middle-aged men and women (ages 55–65) over 20 years and found that moderate drinkers lived longer than did both heavy drinkers and teetotalers. In particular, their data suggested that non-drinkers had a 50% higher death rate than moderate drinkers (1 - 2 drinks per day). Others have criticized this conclusion because the no-alcohol group included people who didn't drink because they were already at a higher risk of death for other reasons such as serious medical conditions, previous cancers, or they were former alcoholics on the wagon. The authors claimed that they controlled for these variables but that is almost impossible to do, and that is one of the reasons that it is difficult to get accurate data from this kind of study. So it may be hard to conclude that moderate drinking significantly increases your lifespan, but it certainly doesn't shorten it.
What about cancer? The publication that started the most recent hype about cancer and alcohol appeared in the April 2013 issue ofThe American Journal of Public Health, and was written by David Nelson MD, MPH and his colleagues. They combined information from others' publications with epidemiologic surveys to determine the number of cancer deaths attributable to alcohol, as well as the types of cancer that were associated. They found that about 3% of all cancer deaths in the US were related to alcohol consumption, with most of it seen in the head and neck, larynx and esophagus. There was still a slight increased risk at low alcohol use (greater than 0 but less than 1 1/2 drinks per day), which led them to conclude, "regular alcohol use at low consumption levels is also associated with increased cancer risk." I looked at their study, and couldn't argue with their conclusion, but I don't think the risk is significant enough to recommend becoming a teetotaler.
Neither does the US National Cancer Institute (NCI). Heavy drinking aside, the NCI does not recommend that people discontinue low or moderate drinking since it would have only a minimal impact on their chance of developing cancer. Some caution is indicated for specific cancers: There is a 1.5 times increased risk of breast cancer in women who drink more than 3 drinks per day compared to non-drinkers; similarly, the risk of colon cancer is 1.5 times increased in people who more than 3.5 drinks per day. Incidentally, 3.5 drinks per day is still well above the level that is considered "low to moderate" drinking, which is usually defined as no more than 1 drink per day for a woman, 2 per day for a man. That being said, lowering your alcohol consumption deserves some consideration if you are anxious to change your odds for these two specific cancers. Nonetheless, the risks from alcohol are still low when compared to the impact of other lifestyle factors. Addressing these factors will have a much greater impact than giving up that beer or wine with your dinner: don't smoke, lose weight if you are over; exercise; eat a high-fiber diet; increase your vegetable and fruit consumption, while limiting red meat; avoid processed food; follow-up on your doctor's cancer screening recommendations for colonoscopy, pap smears, mammography and prostate screening.
Do the positive effects of drinking beer outweigh the negative effects? Moderate alcohol consumption has been reported to lower the risks of heart disease, stroke, hypertension and Type 2 diabetes; for men, it may lower the risk of kidney stones and of prostate cancer; may improve bone health; may prevent brain function decline. Alcohol consumption actually lowers the risk of kidney cancer and of lymphoma. Overall, in most studies, the positive effect was very small, but the beneficial effects of beer are only in moderate drinking, not for those who drink to excess. And of course, there are social and psychological benefits to sharing a beer with friends.
So, is beer drinking good for you? Or bad? Are you healthier if you drink, say, a beer or two per day, or are you worse off? My conclusion as a medical specialist is: it depends. On average, for the general population, drinking a little alcohol is better than abstaining completely. But on an individual basis, it depends on your current health conditions and your risk factors. Are you more likely to die of heart disease or of colon cancer? And if you want to cut down your risk of either condition you must be sure to avoid cigarettes, keep your weight down, exercise, eat a high-fiber diet that is low in red meat and processed foods, and increase your fruit and vegetable intake. The impact of alcohol consumption is likely to be small compared to these lifestyle changes.
What does the Beer Doctor do? As a cancer specialist, my lifestyle includes all of the above recommendations on exercise, weight and diet. I continue to enjoy my beer, but I keep my consumption within the low to moderate range, that is on average about 0.5 to 1 per day, and not every day. For me, the health benefits of drinking beer outweigh the negatives. To your health!
© 2014, Carol Westbrook. This article is from my forthcoming book, To Your Health! The opinions expressed here are my own, and do not reflect those of my employer, Geisinger Health Systems.
Posted by Carol A Westbrook at 12:35 AM | Permalink