Blueberry Consumption Improves Glycemic Control, Triglycerides and Liver Enzymes in US Veterans with Type 2 Diabetes (P06-124-19)

OBJECTIVES: The study investigated the effects of blueberry consumption on biomarkers of glycemic control in US veterans with type 2 diabetes. METHODS: In a double-blind, placebo-controlled parallel study, fifty-five men (mean baseline characteristics: 67 years; weight, 103 kg; body mass index, 34 kg/m(2)) with type 2 diabetes were randomly assigned to 1 of 2 treatment groups for 8 weeks. The treatment groups were either 22 g of a freeze-dried whole blueberry powder (equivalent to 1 cup of fresh blueberries; containing 845 mg phenolics and 470 mg anthocyanins) or 22 g of a blueberry placebo treatment (matched in energy and carbohydrate content to the blueberry treatment). The study participants were asked to consume 11 g of freeze-dried (equivalent to ½ cup of fresh blueberries) blueberry powder or placebo, reconstituted with 240 ml water, with their morning and evening meals along with their typical diet. Fasting blood samples were collected at the beginning and at the end of the study. RESULTS: Fructosamine (275.5 ± 4.1 µmol/L vs. 292.4 ± 7.9 µmol/L, respectively; P = 0.04) and hemoglobin A1C (7.1 ± 0.1% vs. 7.5 ± 0.2%, respectively; P = 0.03) were significantly lower for study participants consuming blueberries for 8 weeks compared with the placebo. In addition, triglycerides (160.6 ± 13.1 mg/dl vs. 183.9 ± 10.7 mg/dl, respectively; P = 0.03), aspartate transaminase (AST) (23.2 ± 1.4 units/L vs. 30.5 ± 2.7 units/L, respectively; P = 0.02) and alanine transaminase (ALT) (35.6 ± 1.5 units/L vs. 48.3 ± 2.9 units/L, respectively; P = 0.0003), were significantly lower for those consuming blueberries compared with the placebo. Glucose, insulin, total cholesterol, LDL cholesterol, HDL cholesterol and body weight were not significantly different after 8 weeks of consumption of blueberries compared with the placebo. CONCLUSIONS: Consumption of 22 g of freeze-dried blueberries daily for 8 weeks results in better glycemic control, such as lowering of fructosamine and hemoglobin A1C. These results along with lower triglyceride concentrations show improvement in the liver enzymes, AST and ALT, which may beneficially affect the cardiometabolic health status of men with type 2 diabetes. FUNDING SOURCES: The U.S. Highbush Blueberry Council; the study is the result of work supported with resources and the use of facilities at the Stratton VA Medical Center, Albany, NY, USA.