Effect of Short-chain Fatty Acids on Aerobic Endurance

Study Overview
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Brief Summary
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Randomized, double-blind, placebo-controlled crossover study designed to determine the effects of increasing colonic short-chain fatty acid (SCFA) content on aerobic endurance in healthy adults, and to identify underpinning mechanisms. In random order, healthy physically active adults will consume provided diets low in fiber and supplemented with SCFA-enriched high amylose maize starch (a poorly digested resistant starch considered a fermentable fiber) or low amylose maize starch (a rapidly digestible starch) for 1-week separated by a ≥2-week washout. At the end of each intervention period, participants will complete an endurance exercise bout followed by a time trial. Biological samples will be collected to assess muscle and whole body metabolism, gut microbiota, inflammation, and gastrointestinal function.

Official Title
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Effect of Short-chain Fatty Acids on Aerobic Endurance

Conditions
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Aerobic Endurance, Metabolism

Intervention / Treatment
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* Dietary Supplement: High-amylose maize starch+acetate/butyrate
* Other: Low-amylose maize starch


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men and women aged 18 - 39 years (active-duty personnel who are 17 yr of age will also be allowed to participate). In good health. Routinely participate in moderate or higher intensity aerobic and/or resistance exercise at least 4 days per week for ≥20 min/d. Meet Army weight for height and body composition standards as defined in Army Regulation 600-9. Self-reports a usual bowel movement frequency of every other day or more often. Willing to refrain from the use of caffeine, alcohol, and nicotine while consuming study diets. Willing to refrain from all dietary supplements beginning 2 weeks prior to study start and throughout study participation. Willing to refrain from consumption of any foods containing live microorganisms (e.g., yogurt, kefir, kombucha) or added prebiotics (e.g. Fiber One products) beginning 2 weeks prior to study start and throughout study participation. Willing to participate in all study procedures. Females must have normal menstrual cycles between 26-32 days in duration; 5 menstrual cycles within the past 6 months; or be using an oral/hormonal contraceptive which contains low-dose estrogen/progesterone to maintain continuous levels throughout the 28-day cycle (i.e., no placebos). Exclusion Criteria: Females who are pregnant, expecting to become pregnant during the study, or breastfeeding. Any of the following medical conditions: Cardiac disease (including arrhythmia or fast or skipped heart beats) Hypertension Musculoskeletal injuries that compromise exercise capability Metabolic or cardiovascular abnormalities (e.g., kidney disease, diabetes, etc.) Disease of the GI tract including, but not limited to diverticulitis, inflammatory bowel disease, irritable bowel syndrome, peptic ulcer disease, Crohn's disease, and ulcerative colitis Allergy to skin adhesive or Lidocaine (or other local anesthetic being used in place of Lidocaine) Suspected or known strictures, fistulas, or physiological/mechanical GI obstruction History of gastric bezoar Swallowing disorders; severe dysphagia to food or pills Implanted or portable electro-mechanical medical devices (e.g., pacemaker) Colonoscopy within 3 months of study participation. Any use of antibiotics or antimycotics, except topical antibiotics/antimycotics, within 3 months of study participation. Regular (i.e., weekly or more frequent) use of over-the-counter medications (including antacids, laxatives, stool softeners, and anti-diarrheals) unless approved by study PI. Use of medication (i.e., diabetes medications, statins, corticosteroids, etc.) that affects macronutrient utilization and/or the ability to participate in strenuous exercise. Anemia (HCT <38 for men and <34 for women) or Sickle Cell Anemia/Trait. Not willing or able to follow all study procedures and diet/exercise restrictions. Allergies, intolerances, unwillingness or inability to eat provided foods and beverages. Following vegetarian/vegan diet or other highly restrictive diet (e.g., ketogenic diet, very high protein diet, Paleo diet, etc.). Any previous blood donation within the previous 8 weeks that when combined with the volume of blood collected for the study within any 8-week period would exceed 550mL.

Ages Eligible for Study
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Minimum Age: 17 Years
Maximum Age: 39 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: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Low-amylose maize starch<br>Low-amylose maize starch (AMIOCA; Ingredion, Inc). | Other: Low-amylose maize starch<br>* Rapidly digestible low-amylose maize starch (0% amylose, 100% amylopectin) sold commercially as AMIOCA (Ingredion, Inc).<br>|
| Active Comparator: High-amylose maize starch+acetate/butyrate<br>High-amylose maize starch, (Hylon VII; Ingredion, Inc.) to which the SCFA acetate or butyrate has been chemically added. | Dietary Supplement: High-amylose maize starch+acetate/butyrate<br>* High-amylose maize starch (HAMS), commercially available as Hylon VII (Ingredion, Inc.), to which the SCFA acetate or butyrate has been chemically added. Hylon VII is a HAMS containing  70% amylose and used in a variety of food products. To produce SCFA-enriched HAMS, Hylon VII is chemically modified through esterification with the SCFA acetate or butyrate.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Run time | Time to complete a 5km treadmill run | Phases 1 and 2, day 8 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Muscle glycogen content | Muscle glycogen content | Phases 1 and 2, day 8 | 
| Plasma glucose turnover | Glucose production, utilization and metabolic clearance rate measured during endurance steady state exercise using 6,6-[2H2] glucose tracer | Phases 1 and 2, day 8 | 
| Whole body substrate oxidation | Carbohydrate and fat oxidation rates measured during endurance steady state exercise using indirect calorimetry | Phase 1 and 2, day 8 | 
| Serum short-chain fatty acid concentrations | Serum acetate, butyrate and propionate concentrations | Phases 1 and 2, day 8. Measured fasted (-300 minutes) and before (0 minutes) and at the end (80 minutes) of steady state endurance exercise | 
| Fecal short-chain fatty acid concentrations | Fecal acetate, butyrate and propionate concentrations | Phases 1 and 2, days 1 and 7 | 
| Intestinal permeability | Small and large intestine permeability measured by saccharide excretion in urine | Phases 1 and 2, day 8 | 
| Intestinal pH | pH of the small intestine and large intestine measured using the SmartPill Gastrointestinal monitoring system | Phases 1 and 2, day 8 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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short-chain fatty acid, microbiome, endurance, fiber, resistant starch, gastrointestinal