Dietary Fibers for Aerobic Endurance

Overseen By J. Philip Karl, PhD

Age: < 65

Sex: Any

Trial Phase: Academic

Sponsor: United States Army Research Institute of Environmental Medicine

Must not be taking: Antibiotics, Antimycotics, Corticosteroids, others

Disqualifiers: Cardiac disease, Hypertension, Diabetes, others

Compensation: Varies

Number of Visits: Unknown

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial aims to determine if a special type of dietary fiber can boost aerobic endurance in healthy, active adults. Participants will follow two different diets: one with a fiber-rich starch that is hard to digest and ferments in the gut (high-amylose maize starch with acetate/butyrate), and another with a quickly digestible starch (low-amylose maize starch). Researchers seek to understand how these fibers affect exercise performance, metabolism, gut health, and inflammation. Individuals who exercise regularly, have normal bowel movements, and are willing to avoid certain foods and drinks during the study might be suitable candidates. As an unphased trial, this study offers a unique opportunity to contribute to scientific knowledge about diet and exercise.

Will I have to stop taking my current medications?

The trial requires participants to stop using dietary supplements and certain foods with live microorganisms or added prebiotics starting 2 weeks before the study and throughout participation. Regular use of over-the-counter medications and certain prescription medications that affect nutrient use or exercise ability is not allowed unless approved by the study's principal investigator.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research has shown that high-amylose maize starch, especially when combined with substances like acetate or butyrate, is generally safe for people. Studies have found that this type of starch is easy to digest and doesn't cause serious side effects. It often improves gut health and supports beneficial bacteria in the intestines.

Moreover, high-amylose maize starch is safe enough for use in food. The FDA considers it generally safe, meaning it's unlikely to cause harm when consumed in normal amounts. While caution is always wise, evidence suggests that this dietary fiber is safe to try in a clinical trial. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Unlike other dietary fibers typically used to boost aerobic endurance, the treatment of high-amylose maize starch combined with acetate or butyrate stands out for its unique composition. Researchers are particularly excited because this treatment introduces short-chain fatty acids (SCFAs) like acetate and butyrate directly into the starch structure, potentially enhancing the gut's health and energy metabolism more effectively than standard dietary fibers. By chemically adding these SCFAs to high-amylose starch, this approach may offer a novel way to support endurance performance, potentially setting it apart from current options that don't incorporate these active ingredients.

What evidence suggests that this trial's treatments could be effective for improving aerobic endurance?

This trial will compare the effects of high-amylose maize starch combined with acetate or butyrate to low-amylose maize starch. Research has shown that high-amylose maize starch, especially when mixed with substances like acetate or butyrate, benefits health. Studies indicate that this type of resistant starch improves gut health by increasing beneficial bacteria. When resistant starch breaks down, it produces essential fatty acids that support gut health. Additionally, resistant starch can help the body manage carbohydrates and fats more effectively, potentially improving energy use during exercise. These benefits suggest that this starch could enhance endurance by boosting metabolism and gut health. ^{1 2 6 7 8}

Who Is on the Research Team?

J. Philip Karl, PhD

Principal Investigator

United States Army Research Institute of Environmental Medicine

Are You a Good Fit for This Trial?

This trial is for healthy, active-duty adults aged 18-39 who exercise regularly and meet Army body composition standards. Women must have normal menstrual cycles or be on low-dose hormonal contraceptives. Participants must avoid caffeine, alcohol, nicotine, dietary supplements, and certain foods before and during the study. Exclusions include GI issues, recent colonoscopy, pregnancy/breastfeeding, metabolic/cardiovascular abnormalities, anemia/sickle cell trait/disease.

Inclusion Criteria

Willing to participate in all study procedures

You are in a good physical condition without any major health problems.

Routinely participate in moderate or higher intensity aerobic and/or resistance exercise at least 4 days per week for ≥20 min/d

Exclusion Criteria

I have a condition like kidney disease or diabetes.

I have severe difficulty swallowing food or pills.

I take medication that affects how my body uses nutrients or my ability to do hard exercise.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment Phase 1

Participants consume a diet low in fiber and supplemented with SCFA-enriched high amylose maize starch or low amylose maize starch for 1 week.

1 week

Daily monitoring

Washout

A washout period of at least 2 weeks between treatment phases.

≥2 weeks

Treatment Phase 2

Participants switch to the alternate diet (either SCFA-enriched or low amylose maize starch) for 1 week.

1 week

Daily monitoring

Follow-up

Participants are monitored for safety and effectiveness after treatment, including biological sample collection and exercise performance assessment.

1 week

End of each treatment phase

What Are the Treatments Tested in This Trial?

Interventions

• High-amylose maize starch+acetate/butyrate
• Low-amylose maize starch

Trial Overview

The study tests how short-chain fatty acids (SCFAs) from high amylose maize starch affect aerobic endurance compared to a placebo of low amylose maize starch in physically active adults. It's a randomized double-blind crossover trial with two one-week diet periods separated by at least two weeks. Endurance exercises are performed post-diet; biological samples are collected to analyze metabolism and gut health.

How Is the Trial Designed?

Group I: High-amylose maize starch+acetate/butyrate Active Control 1 Intervention

High-amylose maize starch, (Hylon VII; Ingredion, Inc.) to which the SCFA acetate or butyrate has been chemically added.

Group II: Low-amylose maize starch Placebo Group 1 Intervention

Low-amylose maize starch (AMIOCA; Ingredion, Inc).

Who Is Running the Clinical Trial?

United States Army Research Institute of Environmental Medicine

Lead Sponsor

Trials

67

Recruited

3,700+

Published Research Related to This Trial

In a study involving 14 healthy adults, both resistant starch (RS) and wheat bran (WB) significantly increased daily faecal output compared to a low-fibre baseline, with RS increasing output to 164.2 g and WB to 194.5 g.

While both types of fibre improved faecal weight, only wheat bran significantly enhanced faecal consistency, indicating that while RS is effective for increasing output, WB may be better for improving stool quality.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Beneficial effects of resistant starch on laxation in healthy adults. Maki, KC., Sanders, LM., Reeves, MS., et al.[2017]

Resistant starch (RS) is gaining attention for its potential health benefits and role as a dietary fiber source, particularly in adults, highlighting its importance in nutrition.

The review discusses various types of RS, factors affecting their formation, and their functional properties in food applications, suggesting that RS can enhance the nutritional value of diets.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Resistant Starch-A Review. Sajilata, MG., Singhal, RS., Kulkarni, PR.[2021]

In a study involving 24 healthy participants, both forms of resistant starch (RS2 and RS3) increased fecal bulk compared to a low-fiber control, suggesting they can enhance digestive health.

The resistant starches also significantly increased the fecal butyrate:SCFA ratio, which is beneficial for colonic health, without affecting blood lipids or glycemic indices.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Physiological effects of resistant starches on fecal bulk, short chain fatty acids, blood lipids and glycemic index. Jenkins, DJ., Vuksan, V., Kendall, CW., et al.[2019]

High amylose corn starch (HAS) diets led to lower feed intake and body weight in animals, while also improving serum lipid profiles and increasing short chain fatty acid (SCFA) levels, indicating potential health benefits from resistant starch.

Whole grain sorghum (S-Wh) resulted in higher body weight and feed intake compared to other diets, suggesting that not all resistant starch sources have the same physiological effects, particularly in terms of cecal fermentation and microbial composition.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

In Vivo Colonic Fermentation of Sorghum (Sorghum bicolor L.): Important Correlations Observed among the Physiological Parameters of Cecum, Liver, Adipose Tissue and Fasting Serum Lipid Profile. Pelpolage, S., Nagata, R., Fukuma, N., et al.[2020]

Propionylated high-amylose maize starches can effectively deliver propionate, a beneficial short-chain fatty acid, to the colon, with concentrations increasing as the degree of substitution (DS) rises.

The fermentation of propionylated starch promotes the growth of beneficial gut bacteria like Roseburia and Blautia, indicating its potential to improve gut microbiota composition and overall colonic health.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

In vitro fecal fermentation of propionylated high-amylose maize starch and its impact on gut microbiota. Xie, Z., Wang, S., Wang, Z., et al.[2019]

In a study involving 14 healthy volunteers, adding 45 g of resistant starch (Hylon-VII) to their diet significantly increased short-chain fatty acid production and reduced colonic mucosal proliferation, suggesting potential protective effects against colon cancer.

The consumption of resistant starch led to a decrease in cytotoxic secondary bile acids, which may be linked to the observed reduction in colonic mucosal proliferation, indicating a possible mechanism for its beneficial effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effect of resistant starch on colonic fermentation, bile acid metabolism, and mucosal proliferation. van Munster, IP., Tangerman, A., Nagengast, FM.[2019]

In a study involving male C57BL/6J mice, a diet supplemented with high-amylose-maize resistant starch type 2 (HAMRS2) led to significant changes in liver metabolism and gene expression, despite no differences in body weight or food intake compared to a control diet.

The HAMRS2 diet resulted in a notable reduction in liver amino acids and increased fecal output and nitrogen, suggesting that HAMRS2 alters gut microbial metabolism, which in turn affects host nitrogen and amino acid homeostasis.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Mice Fed a High-Fat Diet Supplemented with Resistant Starch Display Marked Shifts in the Liver Metabolome Concurrent with Altered Gut Bacteria. Kieffer, DA., Piccolo, BD., Marco, ML., et al.[2023]

In a study involving 120 rats, those fed a diet with butyrylated high-amylose maize starch (HAMSB) showed significantly higher levels of butyrate in their intestines, which was linked to a lower incidence and size of tumors compared to those on a standard low-resistant starch diet.

The results suggest that increasing luminal butyrate through dietary interventions, like butyrylated resistant starch, may provide protective benefits against colorectal cancer, indicating a potential strategy for human dietary recommendations.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effects of high-amylose maize starch and butyrylated high-amylose maize starch on azoxymethane-induced intestinal cancer in rats. Clarke, JM., Topping, DL., Bird, AR., et al.[2021]

In a study involving 20 healthy participants, the addition of novel fibres like soluble maize fibre (SCF) and resistant starch (RS) showed minimal gastrointestinal symptoms and did not significantly affect stool weight or consistency.

SCF was effective in lowering stool pH and increasing short-chain fatty acid (SCFA) production, while RS combined with pullulan (RS+P) notably increased butyrate levels, indicating potential benefits for gut health.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Gastrointestinal effects of resistant starch, soluble maize fibre and pullulan in healthy adults. Klosterbuer, AS., Hullar, MA., Li, F., et al.[2017]

The study of five newly developed maize-based fibers demonstrated that all fibers increased the production of beneficial short-chain fatty acids, particularly butyrate, which is important for colon health, with pullulan showing the highest levels.

All tested fibers acted as prebiotics by promoting the growth of beneficial bacteria like bifidobacteria and Lactobacillus, while also reducing harmful metabolites from protein fermentation, indicating a positive shift in gut microbiota composition.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The effect of the undigested fraction of maize products on the activity and composition of the microbiota determined in a dynamic in vitro model of the human proximal large intestine. Maathuis, A., Hoffman, A., Evans, A., et al.[2022]

A newly developed digestion-resistant retrograded maltodextrin (RRM) shows a high digestion-resistant fraction of about 59.4%, indicating its potential as a beneficial dietary fiber.

Consumption of RRM results in a moderate glycemic response (58.5% compared to glucose), and its fermentation in adults produces significant amounts of short-chain fatty acids (SCFAs), particularly butyrate, which may support various health functions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Physiological and metabolic properties of a digestion-resistant maltodextrin, classified as type 3 retrograded resistant starch. Brouns, F., Arrigoni, E., Langkilde, AM., et al.[2015]

Citations

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pmc.ncbi.nlm.nih.gov

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This study evaluated the effects of 2 levels of intake of high-amylose maize type 2 resistant starch (HAM-RS2) on insulin sensitivity (SI) in participants ...

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sciencedirect.com

sciencedirect.com/science/article/pii/S1756464622001645

Health benefits of resistant starch: A review of the literature

Resistant starch may improve carbohydrate and lipid metabolism and body weight. Resistant starch as a prebiotic improves intestinal function.

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pmc.ncbi.nlm.nih.gov

pmc.ncbi.nlm.nih.gov/articles/PMC10819196/

Resistant starch and the gut microbiome - PubMed Central - NIH

Resistant starch (RS) modulates gut microbiome for health benefits. RS fermentation produces vital volatile fatty acids for gut health.

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sciencedirect.com

sciencedirect.com/science/article/pii/S1051227624002085

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This study was designed to determine the effect of 16 weeks of supplementation with Hi-maize 260 resistant starch (RS) on the gut microbiota, uremic toxins ( ...

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frontiersin.org

frontiersin.org/journals/nutrition/articles/10.3389/fnut.2024.1285169/full

Unraveling the gut health puzzle

Butyrylated high-amylose maize starch (HAMSB) is an edible ingredient that efficiently delivers butyrate to the colon. HAMSB is developed by esterifying a high- ...

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withpower.com

withpower.com/trial/phase-aerobic-endurance-6-2023-fc1a6

Dietary Fibers for Aerobic Endurance

Research on high-amylose maize starch and similar dietary fibers suggests they are generally safe, as they are known to positively affect gut bacteria and ...

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