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Acute Effects of Dietary Fiber on Postprandial Responses in Lean and Overweight Subjects

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
 
ClinicalTrials.gov Identifier: NCT02795559
Recruitment Status : Completed
First Posted : June 10, 2016
Last Update Posted : June 13, 2016
Sponsor:
Collaborator:
Canadian Institutes of Health Research (CIHR)
Information provided by (Responsible Party):
Thomas Wolever, University of Toronto

Brief Summary:
It has been suggested that obesity occurs because the colonic microbes in obese individuals, compared to those who are lean, produce more short chain fatty acids during the fermentation of dietary fiber; this means that obese individuals obtain more energy from dietary fiber than lean. On the other hand, it is possible that the ability of colonic short chain fatty acids to improve glycemic control and suppress appetite may be reduced in obese subjects. The aim of this study was to determine the acute effects of 2 fibers commonly used as food ingredients, inulin and resistant starch, on postprandial serum responses of short chain fatty acids, glucose, insulin, free-fatty acids and selected gut hormones in lean and overweight or obese subjects.

Condition or disease Intervention/treatment Phase
Obesity Diabetes Other: Glucose Other: Inulin Other: Resistant starch Not Applicable

Detailed Description:

The human colon (large intestine) contains hundreds of species of bacteria which exist in a symbiotic (mutually beneficial) relationship with their human host. The number and type of colonic bacteria varies in different people. Recent studies show that overweight individuals have different types of bacteria in their colons than lean subjects, and that as overweight subjects lose weight their colonic bacteria change to resemble those in lean subjects. It was suggested that this was because the bacteria in overweight people more efficiently ferment dietary fiber thus producing more SCFAs and providing more energy to the body. However, this is not consistent with other studies showing that high fiber intakes are associated with reduced risk of obesity.

Some studies have shown that overweight people have higher concentrations of SCFA in their stool samples. But the reasons for the difference in stool concentrations of SCFA have not been studied. Stool concentrations of SCFA may differ in lean and overweight people because of differences in type of bacteria in their colons, differences in dietary intakes or maybe because lean and overweight people absorb SCFA produced by bacteria differently.

Therefore, the objectives of this study were to:

  1. determine the relationship between SCFA production and the acute effects of consuming an unabsorbed carbohydrate on blood SCFA, FFA, glucose, insulin, c-peptide and gut hormone responses in lean and overweight subjects
  2. determine the types of bacteria in the stools of lean and overweight subjects
  3. to see if the types of bacteria are correlated with body weight, the composition of the diet, breath gases, fecal SCFA and other demographic and lifestyle factors.

Healthy subjects with a BMI <25 (lean) or between 25 and 35 (overweight or obese; OWO) took part in a 2 phase study. In phase 1 subjects recorded their dietary intake for 3 days and then provided a stool sample for analysis of micro-organisms and short chain fatty acids. In phase 2 overnight fasted subjects were studied on 3 occasions separated by about a week. On each occasion subjects consumed a control test meal of dextrose, or dextrose plus inulin or dextrose plus resistant start and had breath and blood samples taken at intervals over 4 hours. Subjects were then given a standardized lunch and had more blood and breath samples taken over the next 2 hours.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 25 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: Role of Colonic Short Chain Fatty Acids in Obesity: Acute Effects of Inulin and Resistant Starch on Postprandial Short Chain Fatty Acid, Glucose, Insulin, Free-fatty Acid and Gut Hormone Responses
Study Start Date : March 2012
Actual Primary Completion Date : July 2012
Actual Study Completion Date : July 2012

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Dietary Fiber
Drug Information available for: Starch Inulin

Arm Intervention/treatment
Lean
Subjects within the range of desirable body weight (BMI<25)
Other: Glucose
75g glucose dissolved in 300ml water

Other: Inulin
75g glucose plus 24g inulin dissolved in 300ml water

Other: Resistant starch
75g glucose plus 28g resistant starch in 300ml water

OWO
Subjects who are overweight or obese (BMI between 25 and 40)
Other: Glucose
75g glucose dissolved in 300ml water

Other: Inulin
75g glucose plus 24g inulin dissolved in 300ml water

Other: Resistant starch
75g glucose plus 28g resistant starch in 300ml water




Primary Outcome Measures :
  1. Serum acetate response [ Time Frame: 0 to 6 hours after the intervention ]
    Incremental area under the curve of the serum acetate response from the lowest concentration achieved during the first 3 hours to the end of the study (6hr)


Secondary Outcome Measures :
  1. Serum propionate response [ Time Frame: 0 to 6 hours after the intervention ]
    Incremental area under the curve of the serum propionate response from the lowest concentration achieved during the first 3 hours to the end of the study (6hr)

  2. Serum butyrate response [ Time Frame: 0 to 6 hours after the intervention ]
    Incremental area under the curve of the serum butyrate response from the lowest concentration achieved during the first 3 hours to the end of the study (6hr)

  3. Breath hydrogen response [ Time Frame: 0 to 6 hours after the intervention ]
    Incremental area under the curve of the breath hydrogen response from the lowest concentration achieved during the first 3 hours to the end of the study (6hr)

  4. Energy intake [ Time Frame: 3 days ]
    From 3-day diet record, mean energy intake.

  5. Fat intake [ Time Frame: 3 days ]
    From 3-day diet record, mean total fat intake.

  6. Protein intake [ Time Frame: 3 days ]
    From 3-day diet record, mean protein intake.

  7. Carbohydrate intake [ Time Frame: 3 days ]
    From 3-day diet record, mean available carbohydrate intake.

  8. Dietary fiber intake [ Time Frame: 3 days ]
    From 3-day diet record, mean dietary fiber intake.

  9. Fecal microbiota [ Time Frame: 1 day ]
    Ion Torrent V6 16S-rRNA sequencing for comparison of phyla

  10. 0-2 hour Glucose response [ Time Frame: 0 to 2 hours after consuming treatment ]
    Incremental area under the curve of the serum glucose response from fasting to 2 hours.

  11. 2-4 hour Glucose response [ Time Frame: 2 to 4 hours after consuming treatment ]
    Incremental area under the curve of the serum glucose response from 2 to 4 hours.

  12. Second-meal glucose response [ Time Frame: 0 to 2 hours after lunch ]
    Total area under the curve of the serum glucose response for 2 hours after lunch.

  13. 0-2 hour Insulin response [ Time Frame: 0 to 2 hours after consuming treatment ]
    Incremental area under the curve of the serum insulin response from fasting to 2 hours

  14. 2-4 hour Insulin response [ Time Frame: 2-4 hours after consuming treatment ]
    Incremental area under the curve of the serum insulin response from 2 to 4 hours.

  15. Second-meal Insulin response [ Time Frame: 0-to 2 hours after lunch ]
    Total area under the curve of the serum insulin response for 2 hours after lunch.

  16. 0-2 hour c-peptide response [ Time Frame: 0 to 2 hours after consuming treatment ]
    Incremental area under the curve of the serum c-peptide response from fasting to 2 hours.

  17. 2-4 hour c-peptide response [ Time Frame: 2 to 4 hours after consuming treatment ]
    Incremental area under the curve of the serum c-peptide response from 2 to 4 hours.

  18. Second-meal c-peptide response [ Time Frame: 0-2 hours after lunch ]
    Total area under the curve of the serum c-peptide response for 2 hours after lunch.

  19. Free-fatty acid rebound [ Time Frame: 0 to 4 hours after consuming intervention ]
    Increase in serum free-fatty acid concentration from the lowest to the subsequent highest concentration before consuming lunch

  20. Acute total glucagon-like peptide-1 response [ Time Frame: 0 to 4 hours after consuming intervention ]
    Incremental area under the curve of the serum total glucagon-like peptide-1 response from 0 to 4 hours.

  21. Post-lunch total glucagon-like peptide-1 response [ Time Frame: 0 to 2 hours after consuming lunch ]
    Incremental area under the curve of the serum total glucagon-like peptide-1 response from 0 to 2 hours after lunch.

  22. Acute active glucagon-like peptide-1 response [ Time Frame: 0 to 4 hours after consuming intervention ]
    Incremental area under the curve of the serum active glucagon-like peptide-1 response from 0 to 4 hours.

  23. Post-lunch active glucagon-like peptide-1 response [ Time Frame: 0 to 2 hours after consuming lunch ]
    Incremental area under the curve of the serum active glucagon-like peptide-1 response from 0 to 2 hours after lunch.

  24. Acute peptide tyrosine tyrosine response [ Time Frame: 0 to 4 hours after consuming intervention ]
    Incremental area under the curve of the serum PYY response from 0 to 4 hours.

  25. Post-lunch peptide tyrosine tyrosine response [ Time Frame: 0 to 2 hours after consuming lunch ]
    Incremental area under the curve of the serum PYY response from 0 to 2 hours after lunch.

  26. Acute ghrelin response [ Time Frame: 0 to 4 hours after consuming intervention ]
    Incremental area under the curve of the serum ghrelin response from 0 to 4 hours.

  27. Post-lunch ghrelin response [ Time Frame: 0 to 2 hours after consuming lunch ]
    Incremental area under the curve of the serum ghrelin response from 0 to 2 hours after lunch.



Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • over 18 years of age

Exclusion Criteria:

  • Pregnant
  • BMI<18 or >39.9
  • diabetes
  • anaemia
  • use of diuretics of beta-blockers
  • regular user of antibiotics (≥1 course per year over the last 5 years)
  • any use of antibiotics within 3 months
  • use of laxatives, weight reducing agents, pre/probiotics or supplements known to influence gastrointestinal function within 3 months
  • presence of inflammatory bowel disease, malabsorption, motility disorder, gastrointestinal infection, short bowel, or other condition affecting gastrointestinal function
  • liver or kidney disease or major medical or surgical event (within the last 6 months) requiring hospitalization
  • high fibre intake (>30g/day) or other abnormal dietary pattern
  • on a weight-loss diet or not on their habitual diet in the two months prior to the study
  • unwilling or unable to give informed consent and/or comply with study protocol

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02795559


Locations
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Canada, Ontario
Glycemic Index Laboratories
Toronto, Ontario, Canada, M5C 2X3
Sponsors and Collaborators
University of Toronto
Canadian Institutes of Health Research (CIHR)
Investigators
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Principal Investigator: Thomas MS Wolever, MD, PhD University of Toronto
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Responsible Party: Thomas Wolever, Professor, University of Toronto
ClinicalTrials.gov Identifier: NCT02795559    
Other Study ID Numbers: Protocol Reference # 27112
First Posted: June 10, 2016    Key Record Dates
Last Update Posted: June 13, 2016
Last Verified: June 2016
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No
Keywords provided by Thomas Wolever, University of Toronto:
Nutrition
Humans
Obesity
Blood glucose
Dietary fiber
Appetite
Short chain fatty acids
Additional relevant MeSH terms:
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Obesity
Overnutrition
Nutrition Disorders
Overweight
Body Weight