Resistant Starch Wheat for Improved Metabolic Health

Study Overview
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Brief Summary
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The objective of this study is to determine the effect of wheat enriched in resistant starch (RS) on the generation of fermentation products by the lower gut microbes, the fecal microbiota profile, intestinal metabolites, and the glycemic response to a test meal compared to regular wheat.

Detailed Description
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Resistant starch (RS) is a type of dietary fiber that provides fermentable carbohydrate (FC) in the lower bowel yielding positive effects on postprandial glycemia and weight management as well as digestive tract health. RS is defined as the portion of starch resistant to digestion by amylases, allowing it to reach the distal intestine where it can be fermented by the resident intestinal microbiota. A limited number of human studies using RS from high amylose corn have demonstrated that RS increases synthesis of gut peptides that improve glucose homeostasis and insulin secretion. Based on these studies, the FDA has recently approved the following health claims for resistant starch derived from corn (RS2): lowering of blood glucose, blood cholesterol, and blood pressure; increased mineral absorption; improved laxation; and reduced energy intake. The purpose in the proposed proof of concept study here is to show that RS provided in the form of wheat flour products has similar beneficial effects. The investigators aim to further explore the effect of RS on the gut microbiota. The intestinal microbiome is comprised of over one trillion bacterial cells comprised of approximately one thousand species that perform diverse functions ranging from energy harvest, angiogenesis, immunomodulation, and regulation of mood and behavior. Some of the major products of bacterial metabolism include acetate, propionate, and butyrate, the major short chain fatty acids (SCFA). These bioactive fermentation products have been associated with improved glucose homeostasis, attributed, in part, by their interactions with receptors on intestinal cells to augment secretion of glucagon-like peptide-1 (GLP-1), an incretin hormone known to stimulate insulin secretion. This study is a randomized, cross-over design consisting of two 1-week dietary intervention periods as well as a 2-week washout period in between. Subjects will be randomly assigned to receive either RS wheat first or regular wheat first, then will be crossed over to the opposite treatment following a 2-week washout period. Wheat products made from RS wheat and regular wheat will be provided and the volunteers will be instructed to incorporate the products into their usual diet for 7 days. This study will probe the associations between the gut microbiota profiles, fermentation of RS wheat, microbial-mediated alterations in bile acids, and glycemia. The investigators will measure these effects in healthy, middle-aged humans using an interdisciplinary approach that integrates nutrition, microbiology, intestinal physiology, and analytical chemistry.

Official Title
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Resistant Starch Wheat for Improved Metabolic Health: A Proof of Concept Study in Human Subjects

Conditions
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Gut Microbiota, Metabolism, Metabolic Health

Intervention / Treatment
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* Dietary Supplement: Resistant Starch Wheat


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy adults. Healthy means that the candidate reports that s/he feels well and can perform normal activities. Exclusion Criteria: BMI <18.5 and >39.9 kg/m2 Presence of of untreated or uncontrolled metabolic diseases Presence of gastrointestinal disorders that could interfere with the study outcome (i.e. Crohn's disease, Irritable bowel syndrome, Colitis) Use of oral antibiotics within the past 3 months Presence of cancer or other serious chronic disease by self report Current use of prescribed or over the counter weight loss medications Pregnant Lactating Current use of tobacco Dietary restrictions that would interfere with consuming the intervention foods

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Randomized, cross-over design consisting of two 1-week dietary intervention periods as well as a 2-week washout period in between
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Group 1<br>Order of treatments: A. Resistant Starch Wheat B. Regular Wheat | Dietary Supplement: Resistant Starch Wheat<br>* The investigators will be testing high amylose wheat varieties developed by Arcadia Biosciences that have high levels of RS in the endosperm, the source of refined flour. Compared to regular wheat varieties with RS levels of less than 1%, Arcadia's wheat varieties contain between 16% and 34% RS.<br>|
| Experimental: Group 2<br>Order of treatments: A. Regular Wheat B. Resistant Starch Wheat | Dietary Supplement: Resistant Starch Wheat<br>* The investigators will be testing high amylose wheat varieties developed by Arcadia Biosciences that have high levels of RS in the endosperm, the source of refined flour. Compared to regular wheat varieties with RS levels of less than 1%, Arcadia's wheat varieties contain between 16% and 34% RS.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in Gut Microbiota Composition | Gut microbiota community composition will be determined by 16S ribosomal ribonucleic acid (rRNA) gene sequencing from stool samples | Days 1, 7, 22, and 29 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in Glucose Metabolism | Fasting and postprandial measures of blood glucose, insulin, GLP-1 | 0, 1, 2, and 3 hours postprandial | 
| Changes in Gut Microbiota Metabolism | Fasting and postprandial measures of hydrogen and methane in breath | 0, 0.5, 1, 1.5, 2, 2.5, 3 hours postprandial | 
| Changes in Gut Microbiota Metabolism | Fasting and postprandial measures of SCFA and bile acids in plasma | 0, 1, 2, and 3 hours postprandial | 
| Evaluation of Consumer Acceptance | Participant-reported liking and taste | Days 8 and 30 | 
| Dietary Intake | 24-hour dietary recalls | Days 3, 5, 8, 25, 27, and 30 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Gut Microbiota, Glycemic Response, Resistant Starch, Fiber