It has been a well-known fact that consuming nuts, especially walnuts rich in Omega 3 fatty acids, can benefit heart health. A new study has determined how eating walnuts changes the gut microbe to help promote heart health.

In a study presented at the annual meeting of the American Society for Biochemistry and Molecular Biology, researchers from Texas Tech University and Juniata College in Huntingdon, Pennsylvania, revealed how eating walnuts may benefit the heart.

"Research has shown that walnuts may have heart-healthy benefits like lowering cholesterol levels and blood pressure.This motivated us to look at how walnuts benefited the gut microbiome and whether those effects led to the potential beneficial effects. Our findings represent a new mechanism through which walnuts may lower cardiovascular disease risk," Mansi Chandra, who presented the study, said.

For the study, 35 participants with a high risk of cardiovascular disease were selected. The researchers used three types of diet on the participants: one that has whole walnuts, one without walnuts but with the omega-3 fatty acid alpha-linolenic acid (ALA) and polyunsaturated fatty acid, and the third one without walnuts but with oleic acid for the same amount of ALA found in walnuts.

The participants followed each diet for six weeks, with a break in between. The researchers collected fecal samples shortly before they completed a diet and evaluated them using metatranscriptomics, the study of gene expressions of gut microbes, to understand the changes with each diet.

At the end of the study, participants on the walnut diet had higher levels of Gordonibacter bacteria and amino acid L-homoarginine in their guts.

"This bacterium converts the plant polyphenols ellagitannins and ellagic acid into metabolites that allow them to be absorbed by the body. Participants consuming the walnut diet also showed higher levels of expression for several genes that are involved in important metabolic and biosynthetic pathways, including ones that increase the body’s production of the amino acid L-homoarginine," the study reveals.

More study is required to confirm these observations as it was conducted among a small group of people who were at risk for heart disease. Further research will help to understand how it works for larger groups of healthy people.

Meanwhile, the study shows how dietary interventions based on walnuts reduce the risk for cardiovascular disease."Since a lot of people are allergic to nuts, these findings also suggest that other food supplements that boost the endogenous production of homoarginine may also be helpful," Chandra said.

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