Debbie Nicholson

Regular long-term wild blueberry diets help improve pathologies linked with metabolic syndrome

Wild blueberries are a rich source of polyphenols, which have been examined in numerous and ongoing studies on a wide multitude of health benefits including heart disease, anti-cancer and anti-aging.

Now, new research from the University of Maine, evaluates the effect of wild blueberry consumption on metabolic syndrome.

Metabolic syndrome is a cluster of metabolic risk factors that come together in a single individual. These factors include hypertension, insulin resistance and an increased risk for clotting.

Dr. Klimis-Zacas, PhD, MS, Professor of Clinical Nutrition, School of Food and Agriculture at the University of Maine and co-author of study explained "The metabolic syndrome (MetS) is a group of risk factors characterized by obesity, hypertension, inflammation, dyslipidemia, glucose intolerance and insulin resistance, and endothelial dysfunction.” "MetS affects an estimated 37% of adults in the US ." Many substances found in food have the potential to prevent MetS, thus reducing the need for medication and medical intervention.”

This study evaluates the effect of wild blueberry consumption on the biomechanical properties of the aorta in the obese Zucker rat (OZR), a model of the metabolic syndrome.

"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." said Dr. Klimis-Zacas.

According to researchers, no specific data available on the effects of WB (wild blueberries) on endothelial function as related to the metabolic syndrome. For the first time researchers evaluated the effect of f WB consumption on the biomechanical arterial properties of the aorta in the obese Zucker rat (OZR), which is a valid experimental model of MetS.

For the study 36 male Zucker rats and and 36 male lean Zucker rats were used in this study.

Animals from each group were randomly assigned to either a control or a WB-enriched diet for 8 weeks, from ages 8 to 16 weeks. Rats were caged individually and food consumption was recorded daily nd rat weight was measured weekly.

The results showed wild blueberry consumption (2 cups per day, human equivalent) for eight weeks was shown to regulate and improve the balance between relaxing and constricting factors in the vascular wall, improving blood flow and blood pressure regulation of obese Zucker rats with metabolic syndrome.

The researchers write “We speculate that the main biological effect of WB consumption on endothelial function of OZR is related to its antioxidant and anti-inflammatory action, resulting in down-regulation of iNOS expression.”

In closing Dr. Klimis-Zacas comments "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." Thus, this new study shows even greater potential such that "by normalizing oxidative, inflammatory response and endothelial function, regular long-term wild blueberry diets may also help improve pathologies associated with the MetS."

This study is published today in the journal Applied Physiology, Nutrition, and Metabolism.

The wild blueberries were provided as a composite by Wyman’s (Cherryfield, Maine, USA) and processed following standard procedures to obtain a freeze-dried powder (FutureCeuticals, Momence, Ill., USA).


Slideshow; Health Benefits of Wild Blueberries