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Walnuts improve heart health by altering the gut microbiome 

A team of scientists led by Texas Tech University (TTU) has recently found that introducing walnuts in our diets could provide significant heart benefits by altering our gut microbiome in a way that increases the production of the amino acid L-homoarginine. The lack of this particular amino acid has been linked to higher risk of cardiovascular disease.

“Research has shown that walnuts may have heart-healthy benefits like lowering cholesterol levels and blood pressure,” said Mansi Chandra, an undergraduate researcher at Juniata College, who will present the study findings at Discover BMB, the annual meeting of the American Society for Biochemistry and Molecular Biology (March 25–28, Seattle). “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.”  

To investigate the gene expression of gut microbes, the experts used metatranscriptomics, a recently developed technology employed to quantify gene expression levels and monitor how these levels shift in response to various conditions, including dietary changes.

“To our knowledge, this is the first study to use metatranscriptomics analysis for studying the impact of walnut consumption on the gut microbiota gene expression. These exploratory analyses contribute to our understanding of walnut-related modulation of gut microbiome, which could be very impactful in learning how gut health impacts our heart health in general,” Chandra explained.

The analysis revealed higher levels of Gordonibacter bacteria –microorganisms that help converting the plant polyphenols ellagitannins and ellagic acid into metabolites which allow them to be absorbed by the body – in the guts of participants following a walnut diet. In addition, the researchers also found higher levels of expression for several genes involved in major metabolic and biosynthetic pathways, including those that increase the organism’s production of L-homoarginine. 

Although more research is necessary to better understand the biological mechanisms underlying these changes in the gut microbiome, this study could eventually help inform dietary interventions to improve heart health based on walnuts.  

“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 concluded.

By Andrei Ionescu, Staff Writer

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