Health Effects of Grain Foods in Adults

Overview

This study will assess the effects of eating whole grain foods versus refined grain foods with different amounts of added sugar. It is hypothesized that a diet including grain products will have beneficial effects on taste hedonics, appetite, food/energy intake, body weight, blood pressure, acute and chronic glycemia and acute and chronic lipemia compared to customary diets controlling for added sugars, saturated fats and sodium.

This 16-week, randomized, controlled, parallel-arm, clinical trial will assess the effects of consuming four different categories of grain foods on taste hedonics, appetite, food/energy intake, body weight, and blood pressure as well as acute and longer-term glycemia and lipemia. It will also examine the effects of foods varying in grain/carbohydrate composition on the microbiome and microbiota functionality. One hundred and twenty adults will be recruited and randomly assigned to one of four intervention groups. These groups will be defined by the diets they are prescribed. All will be prescribed diets containing approximately 50%; 35% and 15% energy from carbohydrate, fat and protein, respectively. Grain foods will comprise 50% of the carbohydrate component (i.e., 25% of total energy). The grain foods will be assigned to one of four categories based on whole grain content and concentrations of added sugars. The grain foods meeting these criteria will have the following composition: Group 1 - High Whole Grain, Low Sugar 6 servings of whole grain and \<13% energy from added sugars. Group 2 - Low Whole Grain, Low Sugar 3 servings of whole grain and \<13% energy from added sugars. Group 3 - High Whole Grain, High Sugar 6 servings of whole grain and \>13% energy from added sugars. Group 4 - Low Whole Grain, High Sugar 3 servings of whole grain and \>13% energy from added sugars. Detailed Study Design The study measures and timing are outlined in the following table: Screening Week 1 Baseline Week 2 Week 5 Week 8 Week 11 Week 14 Fasting Blood X X X XX MTT X X X Weight X X X X X X Body Composition X X CGM X X X Intake X Hedonics (palatability) X X X Appetite X X X Activity X X X Blood Pressure X X X X X X Microbiota X X X X X Compliance X X X X X MTT = Meal Tolerance Test; DXA= Dual-energy X-ray Absorptiometry; CGM=Continuous glucose monitoring