The Effects of Apple Consumption on Cardiovascular Health in Prediabetics and Type 2 Diabetics

The hypothesis of this study is that the daily consumption of 75 g dried apple powder for twelve weeks will improve arterial stiffness and blood pressure by improving endothelial-mediated vasodilation and vascular sympathetic activity and favorably altering biochemical markers associated with cardiovascular risk and glycemic control compared to a macronutrient-matched control powder. 50 men and women between the ages of 45 and 65 with prediabetes or type 2 diabetes who are overweight or obese will be included in the study. After a two-week run-in phase, eligible men and women will be randomly assigned to one of two treatment groups: 1) 75 g dried apple powder; or 2) 75 g placebo powder daily for twelve weeks. After an initial telephone screening, all participants will be requested to report to the study site for their first visit. On the first visit (screening), participants will be provided with verbal and written explanation of the project. They will then be asked to sign an informed consent form, followed by measuring fasting glucose levels and a medical history questionnaire to confirm prediabetes or type 2 diabetes. Baseline assessments will be performed for medical history, medication use, dietary intake, and physical activity. Qualified participants will be scheduled for their second visit two weeks later (actual baseline data collection) and randomly assigned to their treatment group. On the second (baseline) visit between the hours of 6:00-11:00 A.M., blood pressure and vascular function will be measured followed by blood draw and urine collection. Anthropometrics will be measured. Participants will be provided with their assigned treatment and will receive standard instructions on how to fill out daily diaries for their treatment, and for food and physical activity records. Blood pressure, vascular function, blood draw, urine collection, and anthropometric, body composition, diet, and physical activity assessments will be repeated at 6- (third visit), and 12-week (final visit) intervals. All cardiovascular measurements will be performed between 6:00 to 11:00 A.M., in a quiet temperature-controlled room in the supine position after an overnight fast and 12 hours after the abstinence of caffeine and/or 24 hours after the last bout of moderate to heavy physical activity.