Alcohol Consumption Increases Cancer Risk

In the United States, drinking alcohol is common.

It’s a central beverage at events across our entire social spectrum. From informal backyard cookouts where people drink cold beer, to Friday Happy Hours where people drink all manner of cocktails to wind down after the work week, to swanky clubs where people drink expensive whiskey and imported aperitifs, to wineries in Napa Valley where people take vacations just to spend a weekend sipping wine, alcohol is everywhere.

That’s not a casual observation: it’s backed by hard facts, reported every year by the National Institutes of Health and the National Institute on Alcohol Abuse and Alcoholism (NIAAA).

Here’s the latest data on drinking in the U.S:

· 85% of people in the U.S. have consumed alcohol during their lives

· 69.5% drank alcohol in the past year

· 54.9% drank in the last month

· 25.8% engaged in binge drinking — 4 drinks in 2 hours for women, 5 drinks in 2 hours for men — in the last month

· 6.3% engaged in heavy drinking — more than 14 drinks a week or binge drinking on five or more days — in the past month.

When we read statistics like these, we tend to gloss over figures like we see in the first three bullet points. Of course most people in the U.S. have consumed alcohol in their lives — everyone knows that. The same goes for past year and past month drinking. Everyone knows that most people — whether they’re drinkers or not — have an occasional alcoholic beverage. Some only drink once-a-year on the holidays, and some only have the occasional glass of wine with dinner, or a beer while watching football on Saturday or Sunday.

It’s safe to say that most people have a passing awareness of the big-picture health risks of drinking alcohol.

The Connection Between Alcohol and Cancer

What most people who drink don’t know, however, is that drinking alcohol increases risk of cancer. That’s true for the heavy drinkers identified in the last two bullet points above — people who are at increased risk of alcohol use disorder and need treatment for alcohol addiction — as well as the people identified in the first three bullet points, who consume a modest, moderate amount of alcohol, who are not at high risk of developing a drinking problem, and will probably never experience alcohol addiction.

For decades, scientists have known about the relationship between alcohol consumption and cancer. The American Cancer Society (ACS) links the following forms of cancer to drinking:

· Mouth

· Throat

· Voice Box

· Esophagus

· Colon

· Rectum

· Breast

The Center for Disease Control (CDC) describes how alcohol causes cancer: the culprit is a chemical called acetaldehyde. When we consume alcohol, one by-product is acetaldehyde. This chemical can damage your DNA and prevent any subsequent natural repair. Damaged, unrepaired DNA contains faulty instructions that can cause cells to grow out of control, thereby creating a cancer tumor.

Scientists have known this since the early 2000s, but what they lack is specifics. The interplay of genetics, environmental factors, and behavior is complex. Direct experimental evidence on the connection between specific genes, alcohol, and cancer has been elusive.

A long-term study performed by a team of scientists from Oxford University, Peking University, and the Chinese Academy of Medical Sciences includes an important discovery that changes that: they found a direct link between two alleles (genetic sequences that code for specific traits) and several forms of cancer.

During the study, scientists gathered genetic information from 60,000 men and 90,000 women, then administered questionnaires that tracked their alcohol consumption habits over 11 years. A study of this size and scope is rare. That’s why it caught my eye: with that many participants, it’s possible to make population-level conclusions about genes, alcohol, and cancer.

I’ll discuss those conclusions now.

Low Tolerance for Alcohol, High Risk of Cancer

An aspect of this study that got my attention is that the alleles researchers examined are known as low-alcohol tolerability genes. In most people, the presence of these alleles correlates with significantly lower alcohol consumption compared to people in whom these alleles are not present. Consumption of alcohol by people who carry these alleles leads to two complications:

1. A flushing effect called alcohol flushing syndrome, wherein the face, body, and neck become warm, and pink/red immediately after consuming alcohol. Additional symptoms of alcohol intolerance related to the flushing effect are nausea, headaches, and diarrhea.

2. An accumulation of acetaldehyde in the bloodstream. As you read above, acetaldehyde can lead to damaged DNA, out of control cell growth, and the development of cancerous tumors.

Here’s where the researchers made their novel discovery: men with the low-tolerance alleles who drank anyway were far more likely to develop cancer than men with the allele who did not drink and men and women without the allele who did drink.

Here are the key results from the study:

· Men with the low-tolerance allele drank less frequently and consumed less total alcohol than those without it.

· Men with the low-tolerance allele showed 13–25% lower risk of alcohol-related cancers overall.

· Men who drank regularly despite having the low-tolerance allele had significantly higher risks of head and neck cancer and esophageal cancer.

· Women who drank regularly despite having the low-tolerance allele showed no increased risk of any type of cancer

For me, as a medical professional who’s worked with the consequences of excess alcohol use and alcohol addiction for almost my entire professional career — that’s a very important data set.

I’ll explain why.

First, it establishes that drinking less decreases risk of cancer: the first two bullet points make that case unequivocally. The relationship between a specific gene and alcohol-related behavior — as seen in the first bullet point — had never been identified so clearly in a study before. Next, the men with the allele — who drank less across their lifespan — had a significantly reduced overall risk of getting cancer. This relationship was also news. Finally, the study showed that — after eliminating all other factors that may have contributed to the development of cancer — men who drank despite having the low-tolerance got cancer at a much higher rate than men who didn’t have the allele.

The bombshell here is the last sentence, which is very strong evidence supporting that the presence of excess acetaldehyde — a byproduct of consuming alcohol — increases risk of specific types of cancer.

Public Awareness About Alcohol and Cancer

I happened to find this research right after seeing this article teaser in one of my online news feeds:

“A recent study by the University of Virginia Cancer Center suggests that less than half of Americans understand that drinking alcohol increases your risk for cancer.”

Let me cut to the chase.

Did you know alcohol increases cancer risk?

The way you know, for instance, that smoking cigarettes causes lung cancer?

If not, I understand why. It’s the way we talk about it. Scientists, by habit, speak carefully about the results of their research, because they have to prove everything they say — and prove it beyond the shadow of a doubt. But that’s okay: that’s what the scientific method is for. It ensures that other scientists can check the results of any experiment.

But I digress.

With cigarettes, the messaging is 100 percent clear and unmistakable: smoking causes cancer. With alcohol, on the other hand, none of the messaging is like that. Instead, we say things like “alcohol consumption is associated with increased risk of developing seven types of cancer.”

Most of us check out of that sentence around the phrase associated with increased risk. Nobody checks out of this sentence, though:

Warning: Cigarette Smoking Is Dangerous to Health and May Cause Death from Cancer and Other Diseases.

That’s why people know smoking is bad for their health: the data is in, the results are unimpeachable, and the rest is history. We have warnings like that one on packages of cigarettes. Now — finally — the evidence on the connection between alcohol and cancer has reached the point where scientists like Dr. Pek Kei from Oxford University, a lead author of the China study, can say:

“These findings indicate that alcohol directly causes several types of cancer, and that these risks may be increased further in people with inherited low alcohol tolerability who cannot properly metabolize alcohol.”

Alcohol products have warnings labels about the risk of driving after consuming alcohol and warnings about using alcohol during pregnancy.

Should alcohol products also carry warnings about cancer risk?

Public Support for Cancer Messaging on Alcohol Products

Concerned physicians think so.

In fact, in 2020, an influential group including the American Institute for Cancer Research, the American Society of Clinical Oncology, the American Public Health Association, Breast Cancer Prevention Partners, Consumer Federation of America, Center for Science in the Public Interest, and the U.S. Alcohol Policy Alliance petitioned the U.S. Department of Treasury’s Alcohol and Tobacco Tax and Trade Bureau to include the following warning on alcohol products:

GOVERNMENT WARNING: According to the Surgeon General, consumption of alcoholic beverages can cause cancer, including breast and colon cancers.

They made that recommendation before the research from China appeared.

I am with them 100 percent regarding this recommendation and the China data supports this in a huge way.