Effect of wild blueberry (Vaccinium angustifolium) juice consumption on cardiovascular and inflammatory markers in male participants

Wild blueberries (Vaccinium angustifolium) are rich in antioxidants and may offer a novel approach to treat heart disease due to anti-inflammatory and anti-diabetic properties. Thus, this study examined the effect of human consumption of wild blueberry juice on markers of cardiovascular disease, metabolic syndrome, oxidative stress, and inflammation. Fourteen middle-aged men with cardiovascular risk factors consumed wild blueberry juice for 3 weeks in a single-blind, randomized, placebo-controlled, crossover trial with a 2-week washout period. Exclusion criteria included use of lipid-altering medications or history of inflammatory disease. Compliance was monitored using 3-day food records. Fasting blood samples were taken at the beginning and end of each treatment period, and serum analyzed. In general, results showed trends toward a reduction in metabolic risk factors, although not always reaching statistical significance. There was a decrease in serum glucose [change from baseline: 0.25 ± 0.13 to -0.11 ± 0.08 mmol/L] (p = 0.037) and a trend towards decreased insulin concentrations (p = 0.088) in the treatment group. Insulin resistance (p = 0.066), estimated using the homeostasis model assessment, decreased in the treatment group whereas it increased in the placebo group. Blueberry tended to lower levels of inflammatory cytokines (IL-6, CRP, TNFα) and there were trends toward an increase in plasma adiponectin (p = 0.095), a hormone that inhibits inflammatory processes and enhances insulin sensitivity. These results suggest that dietary blueberry may exhibit cardio-protective and anti-diabetic properties in men. However, additional research with a greater sample size and longer treatment time is needed to further define efficacy and dose.