The Effect of Wild Blueberry Juice Consumption in Women at Risk for Type 2 Diabetes

Abstract

Wild blueberries have a high content of polyphenols, but there is limited data evaluating their health benefits in people at risk for type 2 diabetes. The objective of the study was to investigate whether 100% wild blueberry juice (WBJ) consumption causes biomarker changes in glucoregulatory control or in those that reflect protection against oxidative stress, inflammation or vascular status, all of which are associated with diabetes risk. A single‐blind randomized cross‐over design study was conducted in which women (n = 19, ages 39‐64 y) at risk for type 2 diabetes consumed 240 ml WBJ or 240 ml of a control beverage as part of their free‐living diet for 7 days. Outcome variables included biomarkers of glucose regulation, oxidative stress, and inflammation. Vascular status, assessed by EndoPat, and blood pressure were also evaluated. WBJ consumption produced no significant changes in biomarkers of glucose regulation and surrogate markers of insulin resistance (glucose, insulin, HOMA‐IR and QUICKI); oxidative stress (total 8‐isoprostanes and LDL‐oxidation); inflammation (IL‐6, IL‐10, CRP, TNF‐alpha, ICAM, VCAM, SAA); and vascular status. However, WBJ consumption showed a trend for lowering systolic blood pressure when compared to the control beverage: 120.8 ± 2.2 mmHg in the placebo group vs 116.0 ± 2.2 mmHg in the WBJ group (P = 0.088). Short term intake of WBJ consumption did not have harmful effects on biomarkers of glucose regulation, oxidative stress, inflammation and vascular status in women at risk for type 2 diabetes. In addition, WBJ may improve systolic blood pressure.