Regular Walnut Intake Linked to Reduced Inflammation and Lower Colon Cancer Risk

Recent research conducted by the University of Connecticut School of Medicine has revealed promising health benefits associated with walnut consumption. The study, published in the April edition of Cancer Prevention Research, indicates that incorporating walnuts into one's diet may significantly alleviate systemic inflammation and potentially lower the risk of colon cancer.

Walnuts are rich in ellagitannins, a type of polyphenolic compound that the gut microbiome metabolizes into anti-inflammatory molecules known as urolithins. These compounds have been linked to powerful anti-inflammatory effects and may contribute to cancer inhibition. Researchers led by Dr. Daniel W. Rosenberg, who has dedicated over a decade to studying the health benefits of walnuts, emphasized the importance of these compounds in their findings.

The clinical trial involved 39 participants aged between 40 and 65, all at an increased risk for colon cancer. These individuals were recruited from the Division of Gastroenterology at UConn Health and were subjected to a stringent dietary regimen. Prior to the study, participants refrained from consuming any foods or beverages containing ellagitannins for a week to minimize their baseline urolithin levels. They then included ellagitannin-rich walnuts in their diet for three weeks, during which their health metrics were closely monitored.

At the conclusion of the trial, participants underwent high-definition colonoscopies, allowing researchers to gather critical data. Notably, elevated levels of urolithin A in the participants' urine were found to correlate with increased serum levels of peptide YY, a protein believed to inhibit colorectal cancer. Furthermore, reductions in various inflammatory markers in the blood were particularly pronounced among obese participants, who exhibited a greater capacity for urolithin formation.

Utilizing advanced spatial imaging techniques, researchers gained insights into the cellular interactions occurring within colon polyps removed during the colonoscopies. The findings revealed that higher levels of urolithin A were associated with decreased quantities of specific proteins typically present in polyps, marking a significant discovery regarding walnut consumption and colon health.

Additionally, the study identified a notable reduction in vimentin, a protein linked to advanced colon cancer forms, in the polyp tissues of participants who produced higher levels of urolithin A. These results build on previous research conducted by Dr. Masako Nakanishi, which demonstrated the beneficial effects of walnuts on colon health in cancer-prone mice, paving the way for this clinical trial.

Overall, the research supports the notion that dietary inclusion of walnut ellagitannins can enhance urolithin levels in individuals with appropriate gut microbiomes, while also significantly lowering inflammatory markers, especially in those who are obese. The findings underscore the potential of walnuts as a simple yet effective dietary approach to improving overall health and reducing cancer risk.