Inflammation May Raise Colon Cancer Risk, New Study Says

While inflammation is a necessary bodily response to an acute injury, it can wreak havoc on your body and brain when it becomes systemic and chronic. Chronic inflammation has been accused of being the culprit behind many chronic diseases, from heart disease, diabetes and chronic lung conditions to cancer, autoimmune diseases and arthritis. It’s been implicated in cognitive decline and constipation—and it even ages you faster. 

There are several potential causes of chronic inflammation, including excessive alcohol consumption, environmental factors, poor diet quality, stress and an inadequate amount of quality sleep. Inflammation can also mess with the gut’s microbiome, disturbing the delicate balance between beneficial and unhealthy bacteria. 

While we know there’s a connection between inflammation and cancer, as well as inflammation and gut health, what might this look like regarding colon cancer? After all, colorectal cancer is the fourth most common cancer in America, and the fourth leading cause of cancer-related deaths in the U.S.

Researchers at the University of South Florida and Tampa General Hospital Cancer Institute wanted to know, too, so they took a microscopic view of colon cancer tumors. Here’s what their study, published on December 10, 2024, in Gut, found.

How Was This Study Conducted?

Using microscopes, researchers examined 40 tumors from patients with colon cancer and compared them to 40 normal tissue samples that were used as controls. They were looking to see if there were any signs of inflammation within the tumors themselves compared to non-cancerous tissue from the colon.

Specifically, they were conducting a lipid analysis. Lipids include various types of fatty acids, like many natural oils, waxes and steroids. They can be helpful, as in the case of healthy fats like olive oil and omega-3s, or harmful, as in the case of an overabundance of omega-6 fatty acids that come from seed oils in ultra-processed foods. These harmful lipids tend to be inflammatory. 

Ideally, we have a balance of inflammatory lipids, which go to work when we are injured, and anti-inflammatory lipids, which kick in to help resolve the inflammation and aid in the healing process. Researchers found that there was a significant imbalance in these types of lipids in the colon cancer tumors. 

What Did the Study Find?

“We found that colorectal cancer tumor samples have a significant elevation of pro-inflammatory lipid mediators and few if any pro-resolving lipid mediators,” explains Timothy Yeatman, M.D., Ph.D., associate director of translational research at the Tampa General Hospital Cancer Institute and one of the lead study authors. “That means the [colorectal cancer tumors] are chronically inflamed and that the microenvironment surrounding the tumor cells is likely immunosuppressed, allowing them to grow and progress.”

Yeatman reflects on a quote from the German physician, Rudolf Virchow, from over a century ago who proposed that cancer is like a chronically inflamed, poorly healing wound.   

“The inflammation likely stems from an over-abundance of omega-6 versus omega-3 lipids in our diets as a result of modern approaches to food production,” says Yeatman. “We call these ultra-processed foods that are rich in seed oils like soybean oil. And while these omega-6 fatty acids are considered essential fatty acids, a large overabundance of them in the diet may lead to a chronic inflammatory state. The end result is that colorectal cancer is like a wound that won’t heal.”

How Does This Apply to Real Life? 

We previously reported on a study that suggested that omega-6-rich seed oils don’t cause inflammation to the extent that some on the internet would have you believe they do—and may even reduce inflammation. 

And yet, this study suggests that they do. So, what gives?

Emily Lachtrupp, MS, RD, explains that “when it comes to omega-6 fatty acids, it’s important to consider the source. The issue isn’t necessarily with omega-6 fatty acids, it’s that most of us are getting high amounts of them from ultra-processed foods, which often are lower in nutrients and may increase inflammation. Almonds and pumpkin seeds, for example, are a nutrient-rich source of omega-6 fatty acids that can be included in a healthy routine. Plus, the balance matters. Most of us are getting too many omega-6s and not enough omega-3 fatty acids. Cutting back on processed foods and prioritizing foods rich in omega-3s, like salmon and tuna can help.”

Yeatman also offers a challenge and recommends eating as clean as you can. “These ‘other things’ are often preservatives, colors, flavor additives, etc. We do not yet fully understand their impact on the microbiome of the gut, which may directly regulate lipids and immunity in the gut.”

Plus, there are anti-inflammatory foods that you can add to your plate just about every day, whether it’s having salmon for dinner, some avocado at breakfast or a handful of nuts for a quick snack. Opting for more foods that offer lots of healthy omega-3 fats or pack a big punch of antioxidants can help you eat colorful, balanced meals throughout the week, which is always a win for your health.

The Bottom Line

A new study in Gut found that colon cancer tumors have an imbalance of inflammatory and anti-inflammatory lipids, which suggests that chronic inflammation could raise the risk of colorectal cancer.

To tamp down chronic inflammation, try to eat a variety of foods to get the nutrients you need to support a healthy gut, which can help keep inflammation under control and reduce disease risk. This includes eating plenty of omega-3s to balance out the more commonly eaten omega-6s, and focusing on whole foods while limiting ultra-processed foods. Other health habits also play a role in gut health, including physical activity, stress management, sleep and oral hygiene, so consider the big picture when it comes to your health.