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Completed

NCT Number: NCT03427879

Effect of Flavonoids on Gut Permeability in Cyclists

The purpose of this investigation is to test the hypothesis that chronic supplementation with a dairy-based beverage containing a mixture of blueberry, green tea, and cocoa flavonoids (non-nutritive natural plant compounds) will ameliorate exercise-related changes in gut permeability and inflammation. In a previous feeding study in humans, (NCT02728570) a high flavonoid diet (flavonoids at 340 mg/1000kcal) was effective in mitigating gut permeability and inflammation in overweight and obese adults compared to a low flavonoid diet (10mg/1000 kcal). To test this hypothesis, 20 trained cyclists will complete a randomized crossover study with supplementation for 2 weeks with a dairy-based sports beverage containing either a high flavonoid (approximately 620 mg) or low flavonoid (approximately 5mg) beverage. After the two week intervention, cyclists will complete a 1 hour cycling trial (45 min at 65% VO2 max then 15 minute time trial). The primary endpoints will be gut permeability as measured by plasma intestinal fatty acid binding protein (I-FABP) and the differential sugar test. Secondary endpoints will include gut inflammation (measured via fecal calprotectin), plasma cytokines (IL-6, IL-10 and TNFα) and plasma LPS. In addition, the distance completed in the time trial is a secondary endpoint.

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Key information

Conditions

Gut Permeability, Gut Inflammation

Age range

18 year–49 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 1

Primary location

Center for Human Nutrition Studies

Logan, Utah, 84322, United States

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Male or female of any race or ethnicity between 18 to 49 years of age
  • Competed in a road race or triathlon in past 12 months
  • Free of chronic disease and GI conditions
  • Train at least 3 times per week, 1 hour at a time on average
  • Willing to prepare and consume provided pre-workout beverage daily
  • Maintain weight (no more/less than 5 kg change)
  • Willing to avoid consumption of high flavonoid foods/supplements, large dose vitamin and mineral supplements, and NSAIDs or other medications known to affect inflammation during study period
  • Willing to provide urine, stool, and blood samples

Exclusion criteria

  • Age <18 or >50 years
  • Medical history of heart disease, hypertension, diabetes, Crohn's disease, IBS, colitis, celiac disease, inflammatory or autoimmune disease, and lactose intolerance
  • Uncontrolled hypertension: diastolic blood pressure >95 mm Hg or systolic blood pressure >160 mm Hg
  • For women: pregnancy, breast feeding or postpartum <6 months
  • Food allergies or restrictions to treatment/placebo beverages
  • Chronic use of NSAIDs
  • Consumption of flavonoid supplements <1 month prior to study start
  • Antibiotic use <3 months prior to study start
  • Other conditions (medical, psychiatric, or behavioral) that may present a safety hazard to the participant or interfere with study participation, as determined by the principal investigators

Treatment and study plan

Low flavonoid beverage

Drug

A low flavonoid, sports nutrition recovery beverage will be prepared from milk (78%), sugar (8.6%), maltodextrin (8.6%), placebo blueberry powder (2.4%), alkalized cocoa powder (1.6%), and whey protein isolate (0.6%). The beverage will contain approximately 5mg flavonoids per serving.

High flavonoid beverage

Drug

A high flavonoid, sports nutrition recovery beverage will be prepared from milk (78%), sugar (8.6%), maltodextrin (8.6%), blueberry powder (2.4%), cocoa powder (1.6%), green tea extract (0.1%) and whey protein isolate (0.6%). The beverage will contain approximately 620 mg flavonoids per serving.

Primary outcomes

  1. Urinary lactulose:mannitol ratio by gas chromatography

    Time frame: Three weeks

    Measure of gut permeability from mouth to end of small intestine. Ratio of urinary lactulose to mannitol after subject consumes a beverage containing these sugars. Sugars in urine are measured by gas chromatography with flame ionization detection.

  2. Plasma intestinal fatty acid binding protein (i-FABP) by ELISA

    Time frame: Three weeks

    Marker of gut wall integrity. i-FABP is measure by enzyme-linked immunosorbent assay in plasma of subjects after the time trial.

Secondary outcomes

  1. Fecal calprotectin by ELISA

    Time frame: Three weeks

    Secondary endpoint for intestinal inflammation. Calprotectin is measured in fecal samples by enzyme-linked immunosorbent assay.

  2. Urinary sucralose:mannitol ratio by gas chromatography

    Time frame: Three weeks

    Secondary measure of gut permeability from mouth to end of colon. Ratio of urinary lactulose to mannitol after subject consumes a beverage containing these sugars. Sugars in urine are measured by gas chromatography with flame ionization detection.

  3. Serum soluble tumor necrosis factor (TNFa) by ELISA

    Time frame: Three weeks

    One of four secondary endpoints for systemic inflammation. The cytokine, TNFa, is measured in plasma by enzyme-linked immunosorbent assay.

  4. Serum soluble interleukin-6 (IL-6) by ELISA

    Time frame: Three weeks

    One of four secondary endpoints for systemic inflammation. The cytokine, IL-6, is measured in plasma by enzyme-linked immunosorbent assay.

  5. Serum soluble interleukin-10 by ELISA

    Time frame: Three weeks

    One of four secondary endpoints for systemic inflammation. The cytokine, IL-10, is measured in plasma by enzyme-linked immunosorbent assay.

  6. Serum endotoxin by ELISA.

    Time frame: Three weeks

    One of four secondary endpoint for systemic inflammation. The bacterial cell wall product is measured in plasma by enzyme-linked immunosorbent assay.

  7. Distance ridden in time trial

    Time frame: One Day

    Subjects will complete a 15m time trial on a bike after each dietary intervention. The distance covered in each time trial will be measured by the computer on the exercise bike.

  8. Rating of perceived exertion by questionnaire.

    Time frame: One Day

    Subjects will complete a 15m time trial on a bike after each dietary intervention. This measure is a subjective measure of the difficulty of the work. Subjects will provide the ratings orally during the time trial.

Sponsors and collaborators

Lead sponsor

Utah State University

Other

Registry information

Important dates

Study start
2018
Primary completion
2019
Study completion
2019
First posted
Feb 9, 2018
Registry last updated
Feb 25, 2021

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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