Eat walnuts, it’s good for your microbiota!

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Considered as “super foods,” walnuts may help us live longer and healthier lives. But how? Probably by changing the composition of the intestinal microbiota.


The consumption of walnuts, which are rich in omega-3s, fiber, and antioxidants, may reduce the risk of cardiovascular diseases and cancer. To test the hypothesis that they act by changing the composition of the intestinal microbiota, American researchers compared the composition of the intestinal flora in two groups of rats, one which was fed walnuts and the other which received calorie-comparable substitutes (same quantity of protein, fat, and fibers, but from other types of food). In addition to being much more diverse, the intestinal microbiota of the “walnut” group rats had, among other things, more Firmicutes and fewer Bacteroidetes than rats in the control group. This difference in microbial composition translated into changes in the functional abilities of the microbiota, promoting functions like the synthesis of bile acids and lipid transport. Furthermore, the microbial population of “good” bacteria was larger in the walnut-eating group, suggesting a role for these oily foods in prebiotics. Although the results need to be confirmed in humans, do we really need to wait until then to add more walnuts to our diets?


Byerley et al. Changes in the gut microbial communities following addition of walnuts to the diet. Journal of Nutritional Biochemistry 48 (2017) 94-102.