Fat Diet Promotes Deadly Colon Cancer
By Stephanie Ronco and James J. Kenney, PhD FACN
Source: foodandhealth.com
Research shows that levels of the oral and gut bacterium Fusobacterium nucleatum (F. nucleatum) increase when people shift from a low-fat, high-fiber diet to a Western-style diet high in fat and low in plant fiber. Elevated F. nucleatum has been linked to shorter life expectancy, with higher rates of cardiovascular and cancer-related deaths. In large prospective studies of health professionals, colorectal cancers containing F. nucleatum were significantly more aggressive and more likely to be fatal than tumors without the bacterium. Among 137,217 participants followed over time, researchers identified 1,019 colorectal cancer cases—125 F. nucleatum–positive and 894 negative. Prudent diets rich in fiber and low in fat were associated with reduced risk of the F. nucleatum–positive cancers, but not the less aggressive negative tumors.
Western dietary patterns high in red and processed meats also promote inflammation, which may contribute to these outcomes. Researchers use the Empirical Dietary Inflammatory Pattern (EDIP) score—based on intake of 18 food groups—to estimate a diet’s inflammatory potential. Higher EDIP scores reflect more pro-inflammatory diets and are associated with elevated markers such as interleukin-6 (IL-6), C-reactive protein (CRP), and tumor necrosis factor receptor levels, all linked to cardiovascular disease and aggressive cancers. Long-term follow-up of more than 124,000 individuals over 28 years found 951 colorectal cancer cases with F. nucleatum in tumor tissue, reinforcing the link between inflammatory diets, altered gut microbiota, and more dangerous cancers.
Research from Columbia University, led by Yiping Han, has clarified how F. nucleatum promotes tumor growth. The bacterium produces a molecule called FadA adhesin that activates cancer-related signaling pathways in colon cells. Importantly, it stimulates growth in cancerous cells but not healthy ones. Dr. Han’s team discovered that cancer cells express a protein called Annexin A1, which enables F. nucleatum to bind and proliferate. The bacterium also increases Annexin A1 production, creating a positive feedback loop that accelerates tumor progression. Analysis of 466 colon cancer patients showed that higher Annexin A1 expression predicted worse outcomes, regardless of stage, age, or sex.
Bottom Line:
While this research may eventually lead to new treatments to prevent deaths from aggressive colon cancers, it also reinforces what we already know about prevention. Adopting a diet rich in whole fruits, vegetables, whole grains, and beans—and low in refined grains, saturated-fat–rich red and processed meats, and sugar-sweetened beverages—can help reduce colon cancer risk. Choosing coffee and tea with little or no added sugar is preferable. Limiting high-fat, calorie-dense foods and staying physically active also help prevent excess weight gain. This is important because higher body fat levels, particularly central adiposity, are associated with increased risk of colon cancer, postmenopausal breast cancer, and more aggressive prostate cancer.
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