“These blood pressure–lowering effects are achievable with simple changes to the daily diet,” Dr. Cassidy said.
“Incorporating flavonoid-rich foods into the diet can have clinically relevant reductions in systolic blood pressure and pulse pressure, and a healthy gut microbiome is important to break down flavonoids to a more cardioprotective form,” she said.
“Our findings indicate future trials should look at participants according to metabolic profile in order to more accurately study the roles of metabolism and the gut microbiome in regulating the effects of flavonoids on blood pressure,” said Dr. Cassidy.
“A better understanding of the highly individual variability of flavonoid metabolism could very well explain why some people have greater cardiovascular protection benefits from flavonoid-rich foods than others.”
‘Interesting’ data
“The data are interesting,” David Jenkins, MD, PhD, DSc, professor of medicine and nutrition at the University of Toronto, said in an interview.
“Berries and red wine appear to be associated with lower systolic blood pressures. Lower blood pressures have been found in general in people who consume more plant-based diets, especially those high in fruits and vegetables,” noted Dr. Jenkins, who was not involved with this study.
“Berries and grapes high in polyphenols may have many health benefits as antioxidants, and in a recent study have been shown to reduce cardiovascular mortality. The change in chronic microflora is also of interest as this will change with increased fruit and vegetable consumption,” he said.
Perhaps one word of caveat, Dr. Jenkins added: “Alcohol has been found to increase blood pressure and the risk of stroke. Presumably the beneficial effects as seen here were when wine is consumed in moderation.”
Supports recommendations
The study by Cassidy and colleagues supports the dietary recommendations from the American Heart Association (AHA) for heart health, Penny M. Kris-Etherton, PhD, RDN, professor of nutritional sciences, Penn State University, University Park, Pa., and chair, AHA Council on Lifestyle and Cardiometabolic Health, said in an interview.
“The AHA recommends a healthy dietary pattern that emphasizes a variety of plant foods including fruits, vegetables, whole grains, legumes, nuts, and seeds and is low in sodium, saturated fat, and added sugars. Lean protein foods, including plant protein foods, are recommended, and red meat should be limited. If alcohol is consumed it should be done in moderation,” Dr. Kris-Etherton said.
“Based on these AHA dietary recommendations, a wide variety of plant foods will promote consumption of many flavonoids that have demonstrated CVD benefits, such as lowering systolic blood pressure as reported by the authors, as well as promoting healthy endothelial function and having antithrombotic, anti-inflammatory and antioxidant effects,” she said in email.
“This recommended dietary pattern will have other cardiovascular health benefits, such as decreasing LDL cholesterol, due to its very healthy nutrient profile. The exciting new finding reported by Cassidy et al. is that the effects of dietary flavonoids on lowering systolic blood pressure are modulated by the gut microbiome,” Dr. Kris-Etherton said.
“Further research needs to be done to confirm these findings and to identify how different foods affect specific gut bacteria that benefit cardiovascular health.”
The research was funded by grants from the German Research Foundation and the German Federal Ministry of Education and Research. Dr. Cassidy and Dr. Jenkins have disclosed no relevant financial relationships. Dr. Kris-Etherton is a spokesperson for the AHA.
A version of this article first appeared on Medscape.com.