Regular consumption of walnuts may alter gut bacteria to improve colon health and prevent colon cancer
Known to be one of the richest sources of antioxidants and essential nutrients, walnuts have been associated with a number of health benefits including reduced risk of heart diseases, improved brain function and cancer prevention.
Evidence for the anti-cancer properties of this brain nut have been mounting in the recent past with several groups reporting reduction of growth in prostate, colon and rectal cancers in mice.
A recent study by Daniel W. Rosenberg of UConn Health and Dr. George Weinstock of The Jackson Laboratory for Genomic Medicine has shown for the first time that besides suppressing colon tumors, walnuts may also act as a probiotic, build a healthy gut, and offer protection against cancer.
When suppression of colon tumor development was observed in walnut-fed mice, this group analyzed the bacterial communities living in their digestive tracts and found that the microbial communities had changed to a potentially cancer-preventive one. Though the mechanism is not clear, the scientists speculate that these gut bacteria could probably digest the chemical components of walnuts into anti-inflammatory molecules.
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A noteworthy observation from this study was that the effect was more pronounced in males. It was seen that males on walnut-free diets tended to have less-diverse gut bacteria than females and adding walnuts to the diets of male mice changed their bacterial community to resemble those of female mice in either case.
Interestingly, population studies carried out in different parts of the world have indicated a higher and early risk in men than women [USA, Austria, and Germany]. Further diet-based human studies would reveal correlation with these findings, if any.
This year, another report by the California Walnut Commission (CWC) published in the journal Food Science and Biotechnology revealed the suppressive effect of lipid extracts (fatty acids and tocopherols) from walnuts on the self-renewal capacity of cancer stem cells that lead to colon cancer.
Taken together, walnuts might not merely be the sum of their chemical parts but may impact significantly when consumed as a whole since its components pack together a powerful anti-cancer punch against colon cancer, the third most common cancer in the world.
An ounce of walnuts a day could keep colon cancer at bay.