NCT02186353

Processing Responses of Grains (PRO-Grains) Study

Effect of Intact vs. Highly Processed Whole Grains on Insulin Sensitivity and Other Cardiometabolic Risk Factors in Hyperinsulinemic Adults

• Status: Withdrawn
• Phase: N/A
• Study type: Interventional
• Enrollment: 0 (actual)
• Sponsor: Boston Children's Hospital · Academic / Other
• Sex: All
• Age: 18 Years – 35 Years
• Healthy volunteers: Accepted

Summary

The primary objective of this pilot study will be to examine the effects of consuming whole grains, differing in the degree of processing, on insulin sensitivity and other cardiometabolic risk factors. The overall aim will be to assess feasibility of the test diets and to generate preliminary data.

Detailed description

In this pilot study, the investigators will access feasibility and generate preliminary data to systematically address a major question in nutrition: Does food processing, specifically with regard to whole grains (WGs), have an independent effect on outcomes related to diabetes and cardiovascular disease? Whole grains are defined as intact, ground, cracked, or flaked caryopsis (kernel or seed), where the principal components (bran, endosperm, germ) are present in the same proportion as the intact caryopsis. In contrast, refined grains (RGs) are milled to remove the bran and germ, leaving only the endosperm and resulting in lower fiber, iron, and many B vitamins. Several previous studies have shown that consumption of WGs vs. RGs improves insulin sensitivity and decreases risk for chronic disease. However, the effects of consuming WGs may differ depending on degree of processing. While whole grain products contain the three components of the kernel, we hypothesize that consuming the food containing the least processed (and least pulverized) kernels may have beneficial effects on metabolism that decrease disease risk through plausible physiological mechanisms. The investigators propose a partial feeding study using a randomized 3-period crossover design to compare the effects of 1) intact or minimally processed whole grains, 2) highly processed whole grains, and 3) refined grains, each fed for 4 weeks. The primary outcome will be change in peripheral insulin sensitivity. Secondary outcomes include hepatic insulin sensitivity, components of the metabolic syndrome and other cardiometabolic risk factors, arterial stiffness, gut microbiome and fecal short chain fatty acids, and ratings of hunger, satiation, palatability, and acceptability (gastrointestinal symptoms).

Conditions

• Insulin Resistance
• Cardiovascular Disease
• Diabetes

Interventions

Type	Name	Description
BEHAVIORAL	Partial feeding study	Provision of all grain foods where only the processing of kernels used to produce the grain foods will differ among test diets. Each participant will be assigned to complete the three 4-week test diets in random sequence.

Timeline

• Start date: 2014-09-01
• Primary completion: 2015-09-01
• Completion: 2015-09-01
• First posted: 2014-07-10
• Last updated: 2017-04-11

Locations

1 site across 1 country: United States