Whey Protein Effects on Gycemic Control and Vascular Function

Effects of Pre-meal Whey Protein Ingestion on Daily Glycemic Control and Oxidative Stress Mediated Postprandial Inflammation and Vascular Dysfunction Evoked by Consumption of a High-glycemic Meal

Risk for heart and blood vessel diseases is increased when blood sugar rises. Blood vessel dysfunction is common to such diseases. Elevated blood sugar after eating promotes blood vessel dysfunction. Dietary factors other than carbohydrates influence rises and falls in blood sugar. Dietary protein is associated with improved blood sugar control. Whey protein effectively blunts the rise in blood sugar after consuming a carbohydrate rich drink/meal in normal weight and obese adults. This study will investigate the efficacy of drinking a whey protein beverage prior to eating for improved daily blood sugar control in normal weight and obese adults in the "real world." Also, the study will test this dietary approach to reduce blood vessel dysfunction associated with eating a meal that causes blood sugar to rise. 24 normal weight and 24 obese men and premenopausal women (18-50y) will participate. Subjects will wear a sensor to monitor daily blood sugar changes in response to their typically consumed diets for 2 days. Subjects will report to the UCLA CTRC the morning after the monitoring period for measurement of blood vessel function after eating a breakfast cereal meal. Blood samples will be obtained before and after the meal to measure relevant health markers. Subjects will repeat the 2-day diet and breakfast cereal meal challenge after a week or more, and will consume either a chocolate flavored 1) whey protein or 2) gelatin protein (control) shake prior to each meal. Neither subjects nor researchers will know which protein ("double blind"). Subjects will receive the alternate protein intervention after another week or more ("crossover"). We think drinking the protein shake prior to meals will reduce daily blood sugar rises and falls after eating and blunt the blood vessel dysfunction that results from eating the breakfast cereal.

Inclusion Criteria:

• Age 18-50 years
• BMI between 18.5 and 25 or ≥ 30
• Willingness to provide written informed consent

Exclusion Criteria:

• Pregnant or breastfeeding currently or in prior 6 months
• Menopause in women
• Regular consumption of > 1 serving per day of milk/yogurt
• Known heart arrhythmia
• Use of tobacco products
• Any disease/pathological condition known to influence outcomes
• Use of medications/dietary supplements known to influence outcomes
• Recent or planned changes in diet/exercise