Effect of blueberries on the metabolic syndrome

A PubMed search of “blueberry” and “antioxidant” revealed 140 studies  — all based on the results of animal or laboratory studies.

This study is important because researchers at Oklahoma State University, in Stillwater, applied what we know from the lab to humans with the metabolic syndrome.

Metabolic syndrome is a group of risk factors that occur together and increase the risk for heart disease, stroke, and type 2 diabetes.

First, the details.

• 48 adults with metabolic syndrome were randomly assigned to a treatment group for 8 weeks.
  • Group 1 consumed a freeze-dried blueberry beverage (50 grams freeze-dried blueberries, approximately 350 grams fresh blueberries daily).
  • Group 2 consumed an equivalent amount of fluids (960 mL water).
• Anthropometric (size and proportions of the body) and blood pressure measurements, dietary intake, and fasting blood samples were obtained at screening and weeks 4 and 8.

And, the results.

• Declines in systolic and diastolic blood pressures were significantly greater in the blueberry-supplemented group (-6% and -4%, respectively) than in controls (-1.5% and -1.2%).
• The blood glucose concentration and lipid profiles were not affected.
• Oxidized LDL (bad) cholesterol blo0od levels decreased significantly.
  • Oxidized LDL reacts with tissues and produces damage.
• Decreases in blood levels of malondialdehyde and hydroxynonenal (both are markers for oxidative stress) concentrations were greater in the blueberry group (-28 and -17%, respectively) than in the control group (-9 and -9%).

The bottom line?

The authors concluded, “Blueberries may improve selected features of metabolic syndrome and related cardiovascular risk factors at dietary achievable doses.”

8/6/10 14:08 JR