Snacking on walnuts could stave off cardiovascular disease, according to new research published in Medical News Today.
A handful a day boosts bacteria in the gut – with knock-on benefits for the heart, say scientists.
Study lead author Mansi Chandra, an undergraduate at Juniata College in Pennsylvania, said: “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.”
Walnuts are rich in healthy plants chemicals such as polyunsaturated fats and omega fatty acids which combat bad cholesterol.
Regular consumption has been linked to warding off a host of illnesses.
The U.S. team shed fresh light on the phenomenon – tracking walnuts’ heart-healthy powers to changes in the balance of trillions of microbes in our intestines.
They used a state-of-the-art technique called metatranscriptomics to analyze gene expression. It can monitor how levels shift in response to various diets.
Chandra said: “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.”
The analysis used fecal samples from a previous trial involving 35 participants at high risk of cardiovascular disease.
They were put on a two-week standard Western diet and then randomly assigned to one of three others for six weeks – with a break between each.
The first incorporated whole walnuts while the others did not – replacing them with the same amount of omega-3 and fatty acids.
More Gordonibacter bacteria was identified in the gut of those on the walnut diet. It increases the absorption of healthy plant polyphenols and antioxidants.
Walnuts also improved the expression of genes involved in important metabolic and biosynthetic pathways.
They included ones that increase production of an amino acid called L-homoarginine. Individuals with low levels have been found to be more prone to heart disease.
Cardiovascular disease is the world’s number one killer – claiming around 18 million lives a year. It offers hope for walnut-based dietary interventions.
Chandra added: “Since a lot of people are allergic to nuts these findings also suggest other food supplements that boost the endogenous production of homoarginine may also be helpful.”
The researchers now plan to identify the final products of the genes that showed higher levels of expression to better understand the biological mechanisms at work.
The study could help identify other foods or supplements with similar nutritional goodness.
The findings were presented at a meeting of the American Society for Biochemistry and Molecular Biology in Seattle.
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