Colorectal cancer, the second leading cause of cancer-related deaths in the United States, may be fueled by the food on our plates. Researchers at the University of South Florida and Tampa General Hospital Cancer Institute have uncovered a potential link between the Western diet—dominated by ultra-processed foods and unhealthy oils—and the chronic inflammation that drives tumour growth.

The researchers have already made major advancements in the understanding of colorectal cancer. The project's first study examines how processed foods are likely hindering the body's natural healing processes. Their findings will be published online in Gut.

"It is well known that patients with unhealthy diets have increased inflammation in their bodies," said Dr Timothy Yeatman, a renowned physician-scientist and professor of surgery in the USF Health Morsani College of Medicine and associate centre director for Translational Research and Innovation at the TGH Cancer Institute.

"We now see this inflammation in the colon tumours themselves, and cancer is like a chronic wound that won't heal—if your body is living off of daily ultra-processed foods, its ability to heal that wound decreases due to the inflammation and suppression of the immune system that ultimately allows cancer to grow."

According to Yeatman, the findings emphasize the urgent need to reevaluate the components of the Western diet, which typically consists of excessive consumption of added sugars, saturated fats, ultra-processed foods, chemicals and inflammatory seed oils. In previous studies, the USF Health Heart Institute found an imbalanced diet not only impacts colorectal cancer but also plays a role in other diseases, including Alzheimer's, diabetes and cardiovascular conditions.

"Our bodies are designed to actively resolve inflammation through bioactive lipid compounds derived from the healthy fats, like avocados, that we consume," said Ganesh Halade, associate professor in the USF Health Heart Institute and a member of the Cancer Biology Program at TGH Cancer Institute.

"Bioactive lipids are very small molecules derived from the foods that we eat and, if the molecules are coming from processed food products, they directly imbalance the immune system and drive chronic inflammation."

While the molecules are difficult to detect, Halade used a highly sensitive analytical technique to identify trace amounts of lipids in 162 tumour samples from patients at Tampa General Hospital. The tumors were frozen within 30 minutes of removal and transported to his lab via USF and TGH Cancer Institute's Biobank, in collaboration with USF Health Colorectal Surgery and the Gastrointestinal Oncology Program at TGH Cancer Institute.

Inside the tumours, the team observed an excess number of molecules that promote inflammation and a shortage of those that help resolve it and promote healing. These findings pave the way for a new, natural approach—resolution medicine—which focuses on restoring balance in the patient's diet to treat colorectal cancer more effectively.

"A human's immune system can be extremely powerful and drastically impact the tumour microenvironment, which is great if harnessed correctly for health and wellness," Yeatman said. "But not if it's suppressed by inflammatory lipids from processed foods."

Resolution medicine would focus on reversing inflammation using healthy, unprocessed foods rich with omega-3 fatty acids and derivatives of fish oil called "specialised pro-resolving mediators," to restore the body's healing mechanisms along with balanced sleep and exercise.

"This has the potential to revolutionize cancer treatment, moving beyond drugs to harness natural healing processes," Yeatman said. "It's a vital step toward addressing chronic inflammation and preventing diseases before they start."

Early trials using specialized derivatives of fish oil have shown promise in addressing inflammation at its root cause. The trials are underway at TGH Cancer Institute and the team will continue studying resolution medicine and its impact on patient treatment and disease prevention.

Examples of healthy, unprocessed foods: crab, salmon, halibut, spinach, Brussels sprouts, seaweed, algae and grass-fed, pasture-raised meats, etc.

Examples of ultra-processed foods: ice cream, sausages, chips, mass-produced bread, breakfast cereals, doughnuts, carbonated drinks, instant soups, some alcoholic drinks, etc.