A study published in the Journal of Nutrition found changes in the gut bacteria that occur when people eat walnuts might be improving heart health, once again confirming that the gut rules the mind and the body.
What is the gut-heart connection?
With the onslaught of information surrounding the gut microbiome, researchers wanted to better understand the walnut's fat and lipid properties and their impact on gut health.
"We wanted to see if changes in gut health with walnut consumption were related to improvements in risk factors for heart disease," said one study author Penny Kris-Etherton, Ph.D.
And that's exactly what they found.
The study included 42 participants, between 30 and 65 years old, who were overweight or obese. Participants were assigned to three different diets, which they followed for six weeks. One diet included whole walnuts and the other two excluded them but maintained the same level of nutritional value from different sources. Each diet used walnuts or vegetable oil to replace saturated fats.
After analyzing stool samples at the end of six weeks, Kristina Petersen, Ph.D., said, "the walnut diet enriched a number of gut bacteria that have been associated with health benefits in the past."
As one specific strain of bacteria (Eubacterium eligens) increased, blood pressure levels decreased. Another strain (Lachnospiraceae) reduced blood pressure and cholesterol. The other two diets had no effect on heart disease risk factors.
How many walnuts should you be eating to see benefits?
Even minor changes in your diet can lead to long-term improvements. Replacing your typical snack—especially if it's unhealthy—with walnuts should do the trick.
"Eating two to three ounces of walnuts a day as part of a healthy diet could be a good way to improve gut health and reduce the risk of heart disease," Petersen said. (That's around a half of a cup of walnuts.)
Lowering blood pressure and cholesterol by eating walnuts can decrease the likelihood to develop cardiovascular diseases, like heart attacks or strokes.
"The findings add to what we know about the health benefits of walnuts, this time moving toward their effects on gut health," Kris-Etherton said. The researchers are now interested in finding out how walnuts might affect blood sugar.
In case you need more reasons to add them to your diet, walnuts can also relieve inflammation and protect against breast cancer.
Abby Moore is an editorial operations manager at mindbodygreen. She earned a B.A. in Journalism from The University of Texas at Austin and has previously written for Tribeza magazine. She has covered topics ranging from regenerative agriculture to celebrity entrepreneurship. Moore worked on the copywriting and marketing team at Siete Family Foods before moving to New York.