The Role of Dietary Intake and Host Genetics in Gut Microbiome Response to Resistant Starch Consumption

Study Overview
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Brief Summary
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Resistant starch (RS), a type of dietary fiber, was shown to have beneficial effects on human health through its impact on microbes present in the intestine. However, the effects of RS on the gut microbiota and in turn, on human health, can vary between individuals. Consequently, everyone may not reap the same health benefits by eating high amounts of RS. Factors predicting how an individual's gut microbes as well as the beneficial metabolites produced by these microbes respond to RS supplementation would be helpful in developing precision nutrition approaches that maximize the benefits of dietary fiber intake. The objective of this study was to evaluate candidate predictors of gut microbiota response to RS supplementation.

Official Title
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The Role of Dietary Intake and Host Genetics in Gut Microbiome Response to Resistant Starch Consumption

Conditions
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Healthy Volunteers

Intervention / Treatment
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* Dietary Supplement: RS2-control-RS4
* Dietary Supplement: RS4-control-RS2


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Above 18 years of age Willing to consume the supplements provided throughout the duration of the study Exclusion Criteria: History of diabetes, prediabetes or impaired glucose tolerance. Existing, UNTREATED, thyroid condition. Usage of systemic antibiotics (intravenous injection, intramuscular, or oral) within 6 months prior to the study. Acute disease at the time of enrollment. Chronic, clinically significant pulmonary, cardiovascular, gastrointestinal, hepatic, or renal functional abnormality. History of active UNTREATED gastrointestinal disorders or diseases including: i. Inflammatory bowel disease (IBD) ii. Ulcerative colitis (mild-moderate-severe) iii. Crohn's disease (mild- moderate-severe) iv. Indeterminate colitis v. Irritable bowel syndrome (IBS) (moderate-severe) vi. Persistent, infectious gastroenteritis, colitis or gastritis vii. Persistent or chronic diarrhea of unknown etiology viii. Clostridium difficile infection (recurrent) ix. Chronic constipation Suspected state of immunosuppression or immunodeficiency including HIV. History of bariatric surgery. Pregnant or lactating women.

Ages Eligible for Study
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Minimum Age: 18 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
Interventional Model Description: We originally enrolled 196 participants and collected saliva samples for screening to participate in the intervention. Then we enrolled 76 participants in the intervention study. These participants were randomly assigned to one of two parallel arms in the intervention study.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Group A: RS2 first<br>Crackers were provided during each of 3 treatment periods in a crossover design. The 3 types of crackers were matched for total carbohydrate content. Treatment period 1 (10 days): After a 3-day ramp up, participants received 120g of crackers/day containing resistant starch type 2 (30g/day) for 7 days; Treatment period 2 (10 days): Participants received control crackers with 100% digestible starch; Treatment period 3 (10 days): After a 3-day ramp up, participants received 120g of crackers/day containing resistant starch type 4 (30g/day) for 7 days. There were 5-day washout periods between the treatment periods. | Dietary Supplement: RS2-control-RS4<br>* Group A: Treatment 1 = RS2 (Hi-Maize 260), Treatment 2 = Control (Amioca TF), Treatment 3 = RS4 (Versafibe 1490)<br>|
| Experimental: Group B: RS4 first<br>Crackers were provided during each of 3 treatment periods in a crossover design. The 3 types of crackers were matched for total carbohydrate content. Treatment period 1 (10 days): After a 3-day ramp up, participants received 120g of crackers/day containing resistant starch type 4 (30g/day) for 7 days; Treatment period 2 (10 days): Participants received control crackers with 100% digestible starch; Treatment period 3 (10 days): After a 3-day ramp up, participants received 120g of crackers/day containing resistant starch type 2 (30g/day) for 7 days. There were 5-day washout periods between the treatment periods. | Dietary Supplement: RS4-control-RS2<br>* Group B: Treatment 1 = RS4 (Versafibe 1490), Treatment 2 = Control (Amioca TF), Treatment 3 = RS2 (Hi-Maize 260)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Gut microbiome | 16S rRNA gene survey of gut microbial communities | 7 weeks | 
| Fecal short-chain fatty acid concentration | Fecal short-chain fatty acid concentration measurements with ultra-performance liquid chromatography | 7 weeks |