Blueberry-rich Diet May Prevent Metabolic Syndrome

A nutritionist at the University of Maine has found more evidence that wild blueberries, when eaten regularly in high volumes, may help improve or prevent pathologies associated with metabolic syndrome, including diabetes and heart disease.

Writing in the journal Applied Physiology, Nutrition, and Metabolism, nutritionist Dorothy Klimis-Zacas, reports that effects of wild blueberries on Zucker rats -- widely used as models of human metabolic syndrome -- lead to improved cardiovascular benefits.

Metabolic syndrome, sometimes referred to as MetS, is characterized by obesity, hypertension, inflammation, dyslipidemia, glucose intolerance and insulin resistance, and endothelial dysfunction, Klimis-Zacas said.

Nearly 40 percent of US adults are affected by MetS, Klimis-Zacas said, adding that many substances found in food, such as polyphenols, can prevent MetS and improve health overall.

"We have previously documented the cardiovascular benefits of a polyphenol-rich wild blueberry in a rat model with impaired vascular health and high blood pressure," said Klimis-Zacas. "Our new findings show that these benefits extend to the obese Zucker rat, a widely used model resembling human MetS."

"Endothelial dysfunction is a landmark characteristic of MetS, and the obese Zucker rat, an excellent model to study the MetS, is characterized by vascular dysfunction. The vascular wall of these animals shows an impaired response to vasorelaxation or vasoconstriction which affects blood flow and blood pressure regulation."

In the study, Klimis-Zacas gave the Zucker rats the human equivalent of 2 cups of wild blueberries per day for eight weeks. Obese Zucker rats with metabolic syndrome on the wild blueberry diet showed improved balance between the relaxing and constricting factors of the vascular wall, improved blood pressure and blood flow regulation.

The results suggest similar health improvements could be seen in obese humans with metabolic syndrome.

"Our recent findings reported elsewhere, documented that wild blueberries reduce chronic inflammation and improve the abnormal lipid profile and gene expression associated with the MetS," Klimis-Zacas said. "By normalizing oxidative, inflammatory response and endothelial function, regular long-term wild blueberry diets may also help improve pathologies associated with the MetS."