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

12 Participants Needed

Trial Summary

What is the purpose of this trial?

This trial tests if special diets with different types of starch can improve exercise endurance in healthy, active adults by producing beneficial substances in the gut.

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.

What data supports the effectiveness of the treatment High-amylose maize starch+acetate/butyrate for improving aerobic endurance?

Research shows that resistant starch, a component of the treatment, can improve gut health by increasing beneficial short-chain fatty acids and promoting healthy gut bacteria. These changes in gut health might indirectly support better overall health and endurance. ^{1 2 3 4 5}

Is dietary fiber from high-amylose maize starch safe for humans?

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 produce beneficial compounds in the colon. However, most studies have been conducted on animals, so human-specific safety data is limited. ^{2 5 6 7 8}

How does the treatment High-amylose maize starch+acetate/butyrate differ from other treatments for aerobic endurance?

This treatment is unique because it uses high-amylose maize starch, a type of resistant starch that is not fully digested in the small intestine, allowing it to reach the colon where it is fermented by gut bacteria. This fermentation process produces short-chain fatty acids like acetate and butyrate, which may improve gut health and potentially enhance aerobic endurance. ^{2 5 9 10 11}

Research Team

J. Philip Karl, PhD

Principal Investigator

United States Army Research Institute of Environmental Medicine

Eligibility Criteria

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

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

Treatment Details

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.

Participant Groups

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+

Findings from Research

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]

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]

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]

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]

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]

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]

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 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]

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]

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]

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]

References

1. England pubmed.ncbi.nlm.nih.gov

Beneficial effects of resistant starch on laxation in healthy adults. [2017]

2. United States 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. [2022]

3. United States pubmed.ncbi.nlm.nih.gov

Physiological effects of resistant starches on fecal bulk, short chain fatty acids, blood lipids and glycemic index. [2019]

4. England pubmed.ncbi.nlm.nih.gov

Gastrointestinal effects of resistant starch, soluble maize fibre and pullulan in healthy adults. [2017]

5. England pubmed.ncbi.nlm.nih.gov

In vitro fecal fermentation of propionylated high-amylose maize starch and its impact on gut microbiota. [2019]

6. Japan 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. [2020]

7. England pubmed.ncbi.nlm.nih.gov

Effects of high-amylose maize starch and butyrylated high-amylose maize starch on azoxymethane-induced intestinal cancer in rats. [2021]

8. United States 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. [2023]

9. United States pubmed.ncbi.nlm.nih.gov

Resistant Starch-A Review. [2021]

10. United States pubmed.ncbi.nlm.nih.gov

Physiological and metabolic properties of a digestion-resistant maltodextrin, classified as type 3 retrograded resistant starch. [2015]

11. United States pubmed.ncbi.nlm.nih.gov

Effect of resistant starch on colonic fermentation, bile acid metabolism, and mucosal proliferation. [2019]