Have you ever noticed that every month seems to bring a trendy new diet? And yet obesity rates continue to rise and with it a growing number of health problems. That’s why I wrote my new book How Not to Diet. Check it out at your local public library. Welcome to the Nutrition Facts Podcast. I’m your host Dr. Michael Greger.
According to the Journal of the American Medical Association the leading killer of Americans in the year 2000 was tobacco, followed by diet and inactivity. The third-leading killer? Alcohol. About half of alcohol-related deaths were due to sudden causes like motor vehicle accidents; the other half were slower, and the leading chronic cause was alcoholic liver disease.
So today we’re going to look at alcohol and your health. In our first story, we ask if even light drinking can cause cancer, why don’t doctors warn their patients about it?
We’ve known about the possible association between the consumption of alcohol and excessive mortality from cancer for more than a hundred years. Though the evidence is accumulating that alcohol drinking is also associated with pancreatic cancer, prostate cancer, and melanoma, we’re pretty certain that alcohol increases risk of mouth cancer, throat cancer, esophageal cancer, colorectal cancer, liver cancer, voice-box cancer, and breast cancer. Current estimates suggest that alcohol causes about 5.8% of all cancer deaths in these organs worldwide.
Here’s how that breaks down for men and women. In men, alcohol causes mostly head and neck cancers, and gastrointestinal cancers, whereas it’s mostly breast cancer in women. Alcohol appears to cause more than 100,000 cases of breast cancer every year. Yeah, but is that just among heavy drinkers? No. “All levels of evidence show a risk relationship between alcohol consumption and the risk of breast cancer, even at low levels of consumption.”
Now, eating a healthy diet may help modulate that risk. Yeah, alcohol increases the risk of breast cancer, but “a fiber-rich diet may have the opposite effect.” So, eating more whole plant foods may be able to “ease the adverse effects” of alcohol. “Alcohol has been shown to increase sex hormone levels,” like estrogen, which may increase breast cancer risk. But, you see the opposite happen eating fiber-rich foods. “Fiber appears to bind estrogen in the colon” and help flush it out of the body. But, even so, there does not appear to be any level of alcohol consumption that is completely safe from a cancer standpoint.
So, that’s why you see commentaries like this in the medical literature: the “consumption of an addictive carcinogen, cannot be considered a healthy lifestyle choice!” “Thus, the final message on alcohol should be clear: It is toxic, carcinogenic, birth defect-causing, and potentially addictive. By arguing otherwise, scientists can give the alcohol lobby and advertisers the opportunity to manipulate the scientific evidence to place profits” over public health.
They do this through denying the evidence, distorting the evidence, and trying to distract the public’s attention. “The alcohol industry, Big Booze, appears to be engaged in the same kind of extensive misrepresentation of the evidence” for which Big Tobacco is best known.
Yet, they are able to maintain this illusion of righteousness. Alcohol, tobacco, and junk food companies “increasingly seek to present themselves as objective providers of health information about their products.” But, “health information should come from health authorities, not the 21st century’s most successful drug peddlers.”
“Alcohol industries profit hugely from this disconnect though and sometimes even appropriate the cause of cancer prevention in order to promote their carcinogenic product.” Case in point: Mike’s Hard Pink Lemonade. “Join The Fight & Drink Pink” carcinogens, associating “the creation of their pink-ribboned alcohol with the death of one of their employees from breast cancer,” ironically, “contributing to risk in the name of prevention.” Who, after all, can forget Kentucky Fried Chicken’s “Buckets for the Cure” campaign?
Cancer risk is one of the things the alcohol industry won’t tell you. But, why doesn’t your doctor tell you? There’s relatively little public awareness of the link, and the medical community has largely remained silent. The medical profession may be getting more hip to corporate conflicts of interest in general, but “why are we ignoring the alcohol industry?”
In other words: “Why is alcohol cancer’s best-kept secret?” Maybe it’s because the doctors are drinkers themselves. And so, they want to remain in denial over the whole thing.
Not only do most doctors drink; a significant proportion admit to drinking while on call and report encountering fellow physicians on call while apparently impaired. Even though most doctors felt they have an obligation to tell their patients should such a situation arise, guess how many actually do? “Only 12% reported that they” inform their patients when they’ve been drinking.
“The industry has identified the alcohol-causes-cancer message as a considerable threat.” They have a “vested interest in maintaining the status quo of relative ignorance, uncertainty and denial among the general population and their trusted health advisers. “In the face of this, it is time that health professionals set aside any leanings that might stem from their own drinking and convey unreservedly to their patients and the communities they serve that alcohol-causes-cancer.”
In our next story, we ask if alcohol causes cancer and there is no “French paradox,” what about the famous J-shaped curve, where yes, excessive drinking is bad, but light drinkers appear to actually have lower mortality than abstainers?
“Why do we not see the corporate interests of the alcohol industry as clearly as we see those of the tobacco industry?” Well, the alcohol industry has “waged a sophisticated and successful campaign over the last few decades undermining perceptions of the extent of alcohol-related harms to health by framing the argument as a balance of benefits and harms.” Yes, alcohol may be an “intoxicating carcinogen,” increasing cancer risk, but what about reducing heart disease risk? “Policymakers hesitate to introduce effective alcohol policies, or even to support the addition of warning labels, for fear they might undermine or contradict any possible health benefits of alcohol use.”
After all, alcohol consumption clearly raises HDL, the supposed “good” cholesterol, But, sadly, as I already explored, HDL is no longer considered protective, based in part on so-called Mendelian randomization studies, where having a high HDL your whole life doesn’t appear to help, whereas a lifelong reduction of bad cholesterol, LDL, just thanks to luck-of-the-draw genetics, does indeed decrease heart disease risk.
So, the boost in HDL from alcohol may not matter. And, if you look at subclinical markers of atherosclerosis, like the thickening of the wall of your carotid arteries in your neck, those that abstain from alcohol completely seem to be at the lowest risk. And, the same with coronary calcium scores, where, in general, the lower the alcohol consumption, the lower the risk. And, alcohol bumps our blood pressure up a bit as well, which would be expected to raise, not lower, our cardiac risk. So, where did we get this idea that alcohol was good for us? From the famous J curve.
Check it out. If you follow large populations of people over time, in general, the more people drink, the higher their risk of dying prematurely. But the lowest risk, those who tend to live the longest were not those who drink zero, the abstainers, but those who drink moderately, like one drink a day.
That’s why you get some folks recommending that “physicians should counsel lifelong nondrinkers” to take up the habit. Sure, there are statin drugs, but “alcoholic beverages don’t require a prescription, are far cheaper, and certainly more enjoyable.”
Is moderate drinking really protective? Or, is there just something about people who abstain completely from alcohol that puts them in a higher risk category? The reason we suspect something fishy is going on is that abstainers seem to be at higher risk of a whole swath of diseases including, ironically, liver cirrhosis. Compared to lifelong abstainers, those who have never touched the stuff, men and women drinking a little appear to have less liver cirrhosis. Wait, what? How could a little drinking be linked to lower rates of liver cirrhosis? Well, let’s think about it. What makes more sense, that drinking lead to less liver cirrhosis, or liver cirrhosis lead to less drinking? In other words, reverse causation: the so-called “sick quitter effect.”
If you look at studies of smokers, sometimes you see higher mortality rates among those who quit smoking, compared to those that continue smoking. Why? Because the reason they quit smoking is because they got sick. So, of course, sick people die more often than less sick people. That’s why when you classify someone as a non-smoker in a study, you have to make sure they’re a “lifelong nonsmoker” and not just a non-smoker since last Tuesday. Yet, unbelievably, that’s not what they do in most alcohol studies, where instead they misclassify former drinkers as if they were lifelong abstainers. And, look, “individuals with poorer health are more likely to cut down or stop drinking completely,” thereby making current drinkers “‘look good’ in comparison” to those who drink zero, because some of the “abstainers” are just abstaining because they got sick and stopped.
Okay. So, what if you went back to all those studies and corrected the misclassifications, separate out the former drinkers from the lifelong abstainers? We didn’t know until now.
They, indeed, found “drinker misclassification errors” all too common, plaguing three quarters of the studies, and when they controlled for that, the J-shaped curve disappeared. The death versus alcohol relationship became more consistent with a straight line, “linear dose response,” meaning more alcohol, more death: no protection at low levels of consumption.
So: “No apparent benefit of light to moderate drinking” after all, when you use better comparison groups. “Although these results are not what the majority of drinking adults may desire to believe,” the public deserves to hear and to read in more complete and balanced detail the ever-growing evidence that drinking alcohol is very unlikely to improve their health.”
Finally today, we ask what would happen if you effectively randomized people at birth to drink more or less alcohol their whole lives? Would they get more or less heart disease?
Once you remove from studies on alcohol and mortality the systematic error of misclassifying former drinkers as if they were lifelong abstainers, moderate alcohol consumption, like a glass of wine a day, does not appear to be protective after all. “The immediate implication from this new research is that clinicians need to be highly sceptical about the hypothesized health benefits of alcohol consumption and should not advise their patients to drink to improve their life expectancy. This is especially important given increasing awareness of cancer risks from even moderate alcohol use.” Given the cancer risk, if there’s just harms and no benefits, then the ideal alcohol intake on a routine day-to-day basis should really be zero, potentially making it a red-light beverage.
The problem was that many of these population studies classified those that quit drinking in response to ill-health as nondrinkers. This is the problem of reverse causation: instead of abstaining leading to poor health, poor health may have lead to abstaining. It’s like when studies show those who sit around and watch TV have worse health; is more TV leading to illness? Or, is illness leading to more TV? That’s one of the reasons why, if you look at the “hierarchy of evidence,” where higher on the pyramid means stronger evidence, interventional trials, like randomized, controlled trials tend to offer better evidence than observational studies of populations, which can suffer from both reverse causation and confounding factors. For example, light drinkers as a group may be more likely to drink their glass of wine with a salad than a cheeseburger, and that’s why the wine appeared protective. But, sometimes it’s hard to do randomized, controlled trials, like you can’t randomize people to smoke a pack a day for a few decades. So, sometimes you have to base your decisions on observational studies. But now, we have a new tool: “Mendelian randomization.”
“In cases where randomized, controlled trials are not feasible or practical,” this new tool “can provide reliable evidence on the cause-and-effect relationship between exposures and risks of disease.”
It’s like the HDL story. Alcohol does raise your HDL “good” cholesterol levels. But, unfortunately, it seems good cholesterol isn’t any good at lowering heart disease risk after all, based in part on Mendelian randomization studies, where people who were randomly assigned higher HDL levels genetically from birth don’t appear to be protected. Is there any way to study people who were randomly assigned since conception to not drink as much? Remarkably, yes.
Alcohol is detoxified in the liver to carbon dioxide and water by two enzymes. But, in the process, a toxic intermediate metabolite is produced, called acetaldehyde, which can cause unpleasant nausea and flushing sensations. So, if people are born with a slow variant of this enzyme, or a superfast variant of this enzyme, acetaldehyde can build up, making alcohol drinking for these people a relatively unpleasant experience throughout their lives. So, they are just born less likely to drink as much. So, do they have an increased risk of heart disease, like the original observational studies would suggest? No, they have a reduced risk of heart disease. “This suggests that reduction of alcohol consumption, even for light to moderate drinkers, is beneficial for cardiovascular health.”
So, this just “sheds further doubt on the protective association between ‘moderate’ alcohol consumption and heart disease,” which was already plagued with the confounding and bias. “Now the scientific pillars on which it is based appear increasingly shaky,” leading some to suggest “the leaning tower of presumed health benefits from ‘moderate’ alcohol use has finally collapsed.” “Given the harms attributed to alcohol use, it is not surprising that reports suggesting benefits attracted enthusiasm among consumers, the media, and of course the alcohol industry. But these apparent benefits are now evaporating.”
“What conclusions should we draw from this emerging evidence? Firstly, in health as elsewhere, if something looks too good to be true like “butter is back”, it should be treated with great caution. Secondly, health professionals should discourage drinking. Thirdly, health advice should come from health authorities, not from the alcohol industry which should remove all misleading references to purported health benefits,” which are increasingly looking more like “a triumph of spin-doctoring” than good science, “as contrived as the alleged split among scientists over climate change,” advanced by the petroleum industry.
“As an intoxicating, addictive, toxic, carcinogenic drug, alcohol is not a great choice as a therapeutic agent,” even if it does help. There are better ways to prevent heart attacks; namely, diet and exercise (and drugs when necessary). “In contrast to that of alcohol, effectiveness of lifestyle interventions has been demonstrated and these interventions have no abuse potential.” There’s a reason there’s no Appleholics Anonymous.
We would love it if you could share with us your stories about reinventing your health through evidence-based nutrition. Go to NutritionFacts.org/testimonials. We may share it on our social media to help inspire others.
To see any graphs, charts, graphics, images or studies mentioned here, please go to the Nutrition Facts Podcast landing page. There you’ll find all the detailed information you need plus links to all of the sources we cite for each of these topics.
For recipes, check out my How Not to Diet Cookbook. It’s beautifully designed, with more than 100 recipes for delicious and nutritious meals. And all proceeds I receive from the sales of my books goes to charity.
NutritionFacts.org is a nonprofit, science-based public service, where you can sign up for free daily updates on the latest in nutrition research via bite-sized videos and articles.
Everything on the website is free. There’s no ads, no corporate sponsorship. It’s strictly non-commercial. I’m not selling anything. I just put it up as a public service, as a labor of love, as a tribute to my grandmother whose own life was saved with evidence-based nutrition. Thanks for listening to Nutrition Facts. I’m your host, Dr. Michael Greger.