Drinking too much alcohol can raise the risk of many health problems—and new research shows it may be strongly linked to colorectal cancer, especially rectal cancer.
Scientists have now found that drinking heavily over a lifetime increases the chances of getting these types of cancers. On the bright side, quitting drinking may help lower that risk.
The study was published in the medical journal Cancer and looked at data from a large group of U.S. adults who were part of a long-term health study called the PLCO (Prostate, Lung, Colorectal, and Ovarian) Cancer Screening Trial. None of the 88,092 participants had cancer when the study started, and they were followed for about 20 years.
During that time, 1,679 people developed colorectal cancer. When the researchers looked at drinking habits, they found that people who drank heavily—defined as 14 or more alcoholic drinks per week throughout their adult life—had a 25% higher risk of developing colorectal cancer compared to people who drank less than one drink per week on average.
For rectal cancer specifically, the risk was even higher—almost double that of light drinkers.
The study also found that people who drank heavily for many years (consistently through adulthood) had a 91% higher risk of getting colorectal cancer than people who consistently drank very little.
Interestingly, the study found no increased cancer risk in people who used to drink alcohol but had since quit.
In fact, former drinkers were less likely to develop noncancerous colorectal tumors, called adenomas, than current drinkers—even those who drank very lightly. These adenomas can sometimes become cancerous later, so reducing their number may lower cancer risk.
Though the number of former drinkers in the study was small, the findings suggest that quitting alcohol might help bring cancer risk down to the level of those who rarely drink. This is an important discovery and could offer hope to people trying to improve their health by stopping drinking.
Scientists believe alcohol may increase cancer risk because of the harmful substances created when the body breaks down alcohol. Alcohol may also upset the balance of healthy bacteria in the gut, which can affect how the colon works and potentially lead to cancer. However, more research is needed to fully understand how alcohol causes these effects.
Dr. Erikka Loftfield, one of the study’s senior authors and a researcher at the National Cancer Institute, said that this is one of the first major studies to look at how drinking across a person’s life affects both early signs of colorectal cancer (like adenomas) and the disease itself.
She added that while the data on people who had quit drinking was limited, it was encouraging to see that their cancer risk seemed to return to normal.
In short, this study adds to the growing evidence that drinking less alcohol—or quitting altogether—may help reduce the risk of colorectal and rectal cancer. It also shows the importance of looking at drinking habits over a lifetime, not just at one point in time.
If you care about gut health, please read studies about how probiotics can protect gut health, and Mycoprotein in diet may reduce risk of bowel cancer and improve gut health.
For more health information, please see recent studies about how food additives could affect gut health, and the best foods for gut health.
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