Regulation of Postprandial Nitric Oxide Bioavailability and Vascular Function By Dairy Fat

Overview

Cardiovascular disease (CVD) is the leading cause of death in the United States. Short-term increases in blood sugar, or postprandial hyperglycemia (PPH), affect blood vessel function and increase the risk of CVD. Greater intakes of dairy foods have been associated with a lower risk of CVD, but whether these effects occur directly or indirectly by displacing foods in the diet that might increase CVD risk is unclear. Further controversial is the extent to which dietary fat derived from dairy foods regulate the risk of CVD. The health benefits of dairy on CVD risk are at least partly attributed to its ability to limit PPH and resulting PPH-mediated responses leading to vascular dysfunction. This provides rationale to investigate full-fat containing dairy as a dietary strategy to reduce PPH and risk for heart disease. The objective of this project is to define the extent to which full-fat dairy milk compared to non-fat dairy milk protects against PPH-induced vascular dysfunction by reducing oxidative stress responses that limit nitric oxide bioavailability to the vascular endothelium in adults with prediabetes.

This study consists of three, 3-hour postprandial trials in response to consuming the following dietary treatments: 1. oral glucose challenge, 2. oral glucose challenge in combination with non-fat milk, and 3. oral glucose challenge in combination with whole milk. For three days preceding each trial, participants will be provided all meals to standardize physiologic responses to test meals. On each trial day, vascular function will be assessed and blood samples collected prior to and at 30 minute intervals for 3 hours following test meal ingestion.