New research suggests that consuming walnuts may promote healthy gut bacteria, which reduces the risk of developing cardiovascular disease.
Cardiovascular disease is the leading global cause of morbidity and mortality, with a poor diet being the primary risk factor for disease development. Consequentially, there is a dire need to identify and develop the ideal diet for reducing the risk of cardiovascular disease and promoting positive heart health.
New research, from researchers at Penn State University and Juniata College (both PA, USA), has demonstrated the potential health benefits of incorporating a daily portion of walnuts into a healthy diet. It was discovered that walnut consumption resulted in a change in gut microbiota, which in turn promoted positive heart health and reduced the risk of cardiovascular disease.
“Replacing your usual snack — especially if it’s an unhealthy snack — with walnuts is a small change you can make to improve your diet,” remarked study author Kristina Petersen (Penn State). “Substantial evidence shows that small improvements in diet greatly benefit health. Eating 2 – 3 oz 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.”
In a randomized, controlled trial, published recently in The Journal of Nutrition, 42 adults (aged 30-65) at risk of developing cardiovascular disease were recruited and initially placed on a 2-week standard Western diet. Following this, the participants were randomly assigned to one of three different study diets, which involved replacing saturated fats with either vegetable oils or walnuts.
All participants followed each diet for 6 weeks, with a break between each diet period, and fecal samples were collected 72 hours before the participants finished each diet, including the run-in diet, to assess gut microbiota at each stage.
“The walnut diet enriched a number of gut bacteria that have been associated with health benefits in the past,” Petersen explained. “One of those is Roseburia, which has been associated with protection of the gut lining. We also saw enrichment in Eubacteria eligens and Butyricicoccus.”
Additionally, some of these changes in gut bacteria were shown to significantly reduce some risk factors for cardiovascular disease. For example, high levels of Lachnospiraceae – observed after the walnut diet – were found to be associated with reductions in blood pressure, total cholesterol and non-HDL cholesterol.
The researchers found no significant correlation between gut bacteria changes and cardiovascular disease risk factors in either of the other two diets, confirming the researchers’ theory that walnuts can reduce cardiovascular disease risk.
“The findings add to what we know about the health benefits of walnuts, this time moving toward their effects on gut health,” commented Penny Kris-Etherton (Penn State), another author on this study. “The study gives us clues that nuts may change gut health, and now we’re interested in expanding that and looking into how it may affect blood sugar levels.”