Effect of Flavonoids on Gut Permeability in Cyclists

Study Overview
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Brief Summary
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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.

Official Title
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Effect of Flavonoids on Gut Permeability in Cyclists

Conditions
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Gut Permeability, Gut Inflammation

Intervention / Treatment
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* Drug: Low flavonoid beverage
* Drug: High flavonoid beverage


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 49 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: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Low flavonoid beverage<br>Subjects will consume 310 milliliters per day of a dairy-based, low flavonoid, sports nutrition recovery beverage 14 days. | Drug: Low flavonoid beverage<br>* 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.<br>|
| Active Comparator: High flavonoid beverage<br>Subjects will consume 310 milliliters per day of a dairy-based, high flavonoid, sports nutrition recovery beverage 14 days. | Drug: High flavonoid beverage<br>* 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.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Urinary lactulose:mannitol ratio by gas chromatography | 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. | Three weeks | 
| Plasma intestinal fatty acid binding protein (i-FABP) by ELISA | Marker of gut wall integrity. i-FABP is measure by enzyme-linked immunosorbent assay in plasma of subjects after the time trial. | Three weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Fecal calprotectin by ELISA | Secondary endpoint for intestinal inflammation. Calprotectin is measured in fecal samples by enzyme-linked immunosorbent assay. | Three weeks | 
| Urinary sucralose:mannitol ratio by gas chromatography | 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. | Three weeks | 
| Serum soluble tumor necrosis factor (TNFa) by ELISA | One of four secondary endpoints for systemic inflammation. The cytokine, TNFa, is measured in plasma by enzyme-linked immunosorbent assay. | Three weeks | 
| Serum soluble interleukin-6 (IL-6) by ELISA | One of four secondary endpoints for systemic inflammation. The cytokine, IL-6, is measured in plasma by enzyme-linked immunosorbent assay. | Three weeks | 
| Serum soluble interleukin-10 by ELISA | One of four secondary endpoints for systemic inflammation. The cytokine, IL-10, is measured in plasma by enzyme-linked immunosorbent assay. | Three weeks | 
| Serum endotoxin by ELISA. | One of four secondary endpoint for systemic inflammation. The bacterial cell wall product is measured in plasma by enzyme-linked immunosorbent assay. | Three weeks | 
| Distance ridden in time trial | 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. | One Day | 
| Rating of perceived exertion by questionnaire. | 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. | One Day |