Colon Cancer May Have More to Do with Gut Health Than We Realize, New Study Says
- 48 minutes ago
- 3 min read
Key Points
Women with removed colon polyps had gut microbes resembling those linked to colorectal cancer.
Diets high in fiber and low in red meat and sugar supported healthier gut microbes in the study.
Staying active and eating colorful produce may help reduce inflammation and support gut health.
Colorectal cancer is one of the most commonly diagnosed cancers and a leading cause of cancer death. The good news is that most cases start as small, slow-growing clumps of cells called adenomas or polyps. This is why colonoscopies are so valuable—finding and removing a polyp can help stop cancer before it ever begins. But here’s the puzzle that’s long stumped researchers: Even after a polyp is removed, that person remains at higher-than-average risk for colorectal cancer down the line, and no one has fully understood why.
A growing body of research keeps pointing to the same suspect: the trillions of bacteria and other microbes living in your gut. A new study published in Cell Host & Microbe took a close look at women who’d had a polyp removed years earlier and found that their gut microbes still looked different from those of women who’d never had one—and, notably, partially resembled the microbial patterns found in people with colorectal cancer. Here’s what they discovered.
How Was This Study Conducted?
This was an observational study that drew on the Nurses’ Health Study II, a large, long-running research project following female nurses in the U.S. Researchers identified 354 women who’d had an adenoma removed and paired each one with a polyp-free woman of similar age and background, for a total of 708 participants. Stool samples were collected, on average, about 12 years after the polyp had been removed.
From those samples, the team sequenced the gut microbes of all 708 women and analyzed the metabolites (the chemical byproducts microbes and the body produce) in a subset of 184 matched pairs. They then compared these microbial profiles against data from 14 separate colorectal cancer studies, representing roughly 2,100 people, to see how closely the two groups lined up.
What Did the Study Find?
The primary finding is that the gut microbiomes of women who’d had a polyp removed were measurably different from those of the polyp-free group, and those differences partially overlapped with the microbial signatures of colorectal cancer.
Digging deeper, the researchers pinpointed 31 specific microbes that consistently shifted in the same direction in both the polyp group and the cancer datasets. Some were more abundant while others were noticeably depleted. The metabolite analysis told a similar story. Compounds tied to inflammation were elevated in the polyp group, while levels of a protective carotenoid—an antioxidant you get from colorful fruits and vegetables—were reduced.
These microbial patterns were strongly associated with diet and lifestyle. The microbes shared with the cancer group tended to be more abundant in women who ate more red meat and sugar-sweetened beverages, had a higher BMI and were less physically active. The opposite pattern showed up in women who ate more fruit, vegetables and whole grains and moved more.
There are a few limitations to keep in mind. Because the study included only female participants, the findings may not apply to males. Diet and lifestyle information was self-reported, which always leaves room for error. And stool was collected only once, years after each polyp was removed, so researchers couldn’t track how any individual’s microbiome changed over time.
How Does This Apply to Real Life?
The practical upshot is encouraging: The same habits associated with a healthier gut microbiome in this study overlap with advice thats long been linked to lower colorectal cancer risk.
If you want to support a healthier gut, consider these steps:
Prioritize fiber. Fill your plate with whole grains, vegetables, fruits, beans and nuts, which can help feed the beneficial microbes that were depleted in this study.
Go easy on red and processed meat and sugar-sweetened drinks. Both were associated with the less-favorable microbial pattern.
Move regularly. Physical activity tracked with a healthier microbiome among participants.
Eat the rainbow. Colorful produce supplies antioxidants like beta-cryptoxanthin, which was reduced in the polyp group.
Stay on top of screenings. If you’ve had a polyp removed, keep up with the follow-up colonoscopies your doctor recommends.
Our Expert Take
A new study in Cell Host & Microbe found that women who’d had a precancerous colon polyp removed still carried a distinct gut microbiome more than a decade later, one that resembled the microbial patterns seen in colorectal cancer. The microbes involved were closely tied to diet and lifestyle, reinforcing how much your daily habits may shape your gut—and potentially your long-term colon health. While researchers can’t yet say the microbiome directly drives that elevated risk, the findings add to a strong case for eating more fiber-rich, plant-forward foods, staying active and keeping up with recommended screenings.
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