An article published online on July 21, 2010 in the Journal of Nutrition describes the outcome of a trial of obese men and women with metabolic syndrome which found a protective effect for blueberries against several cardiovascular disease risk factors. Metabolic syndrome is a group of factors that include reduced high-density lipoprotein (HDL) cholesterol, high triglyceride levels, hypertension, impaired glucose tolerance, abdominal obesity, and greater oxidative stress and inflammation. Having several of these risk factors increases the risk of developing cardiovascular disease and diabetes. Researchers at Oklahoma State University randomized 4 men and 44 women to receive a beverage containing 50 grams freeze-dried blueberries (equivalent to 2.3 cups fresh blueberries) or an equivalent amount of water daily for 8 weeks. Weight, blood pressure, dietary assessments and blood sample analyses for various factors were conducted at the beginning of the study and at 4 and 8 weeks. At the treatment period's conclusion, those who received blueberries had greater decreases in systolic and diastolic blood pressure compared to the controls. This group also experienced significantly greater reductions in plasma oxidized low-density lipoprotein, serum malondialdehyde and serum hydroxynonenal concentrations, indicating reduced oxidative stress. The authors remark that blueberries have been shown to possess several cardioprotective mechanisms, including antioxidative, antiinflammatory, antihypertensive, antidiabetic, antiobesity and antihyperlipidemic effects. "Our study findings suggest a cardioprotective role of dietary achievable doses of blueberries in men and women with metabolic syndrome, which includes a significant decrease in systolic and diastolic blood pressures and plasma ox-LDL and lipid peroxidation," they write. "Our clinical data are supported by previously reported mechanistic studies and limited human intervention studies using single or mixed berries or anthocyanin extracts. However, our findings specifically show the cardioprotective effects of blueberries in improving features of metabolic syndrome." "These results warrant further investigation and provide some evidence for including blueberries as part of healthy dietary practices," they conclude. |
