Effect of Viscous Soluble Fibres on Body Weight

August 17, 2017 updated by: Unity Health Toronto

Effect of Viscous Soluble Fibres on Body Weight Parameters: Review and Meta-analyses

Abstract:

Background: Obesity is a global pandemic affects all age groups and is independent risk factors for most chronic diseases. Dietary intervention is an essential component of obesity management. Dietary fibre supplements have the potential to facilitate weight reduction based on their viscosity. Up to date, the evidence of effects of some fibres on weight is inadequate, and literature provides insufficient information about the effects of the fibre viscosity in weight management.

Objective: Two systematic reviews and meta-analyses of RCTs will be conducted to evaluate the effectiveness of viscous fibres, (agar, alginate, b-glucan from oat and barley, guar gum, glucomannan, pectin, PGX, psyllium), on body weight reduction.

Methods: Only randomised controlled trials are accepted. The trails must have one of the selected fibres as a supplement, and the outcomes must have body weight, BMI, waist circumference, or body fat percentage. Studies shorter than 4 weeks are excluded. Three databases, (Medline, EMBASE, and Cochrane library), were searched through 04/03/2016.

Results: After removing duplicates, 82 studies will be reviewed in full. Significance: This meta-analysis is the first meta-analysis that is based on fibre viscosity, and it will quantify the effect of each fibre in improving weight loss. It will also direct future research in the best direction to further explore this area.

Study Overview

Status

Unknown

Conditions

Intervention / Treatment

Detailed Description

Background: Obesity is a global pandemic and is an independent risk factor for chronic disease. Dietary intervention is an essential component of obesity management. Observational studies show an inverse relationship between dietary fibres and body weight. Therefore, supplements of dietary fibres have the potential to facilitate weight reduction, possibly on the basis of the viscous properties of the fibre. Viscosity is the ability of gel forming that holds water and increase satiety and decreases the amount of intake food. This ability makes dietary fibre supplements considered as appetite suppressants. To date, the evidence of the effect of dietary fibre on weight is inconsistent and controversial and may be dependent on the ability of fibre to induce viscosity. Three previous meta-analyses on Konjac show inconsistency on the effect and its significance. In addition, other meta-analyses on individual viscous fibres show that some viscous fibre does not has an effect on body weight. This is the first meta-analysis that studies the effect of all these fibres together based on their viscosity.

Objective: Two systematic reviews and meta-analyses of RCTs will be conducted to evaluate the effect of viscous and non-viscous fibres on body weight, BMI, waist circumference, and body fat percentage.

Methods: To meet eligibility criteria, the study should be: randomized, controlled, include one of the selected fibres (agar, alginate, b-glucan from oat and barley, guar gum, konjac, pectin, PGX, Psyllium, and xanthan) as a supplement and one of the required outcomes (body weight, BMI, waist circumference or body fat percentage). Studies shorter than 4 weeks in duration will be excluded. Three databases (Medline, EMBASE, and Cochrane Library) were searched. After the search, a title/abstract screening was done to exclude the ineligible articles before extracting data from full eligible studies. Data were extracted using a PROFORMA. Review Manager 5.3 (RevMan) was used to carry out the analysis using generic inverse variance method (GIVM). Change from baseline and standard deviation were utilized in random effect model to get the pooled mean difference effect. Subgroup analyses were done using meta-regression in STATA to explore confounders. GRADE approach was conducted to evaluate the quality of evidence and the strength of recommendations.

Results: Databases were searched through 04/03/2016 and updated on 11/04/2017. Twenty-seven studies were eligible for analyses . The overall effect of viscous fibres on body weight was a significant reduction of -0.38 kg [95%CI: -0.3, -0.13] (P=0.003). BMI, waist circumference and body fat were also significantly reduced: -0.41 kg/m2 [95% CI: -0.61, -0.21](p = 0.0001) -0.78 cm[95%CI: -1.33, -0.24] (p = ) and -1.28 %[95% CI: -2.09, -0.46] (p = ), respectively.

Significance: This study is the first systematic review and meta-analysis that evaluated separately the effect of viscous and non-viscous fibres on weight in the general population. The analysis may help guide diet recommendations for obesity and identify the effect of fibres to direct future research this area.

Study Type

Observational

Enrollment (Anticipated)

1268

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Ontario
      • Toronto, Ontario, Canada, M5C 2T2
        • The Toronto 3D Knowledge Synthesis and Clinical Trials Unit, Clinical Nutrition and Risk Factor Modification Centre

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Probability Sample

Study Population

This study includes all population types.

Description

Inclusion Criteria:

  1. Must be a randomized controlled clinical trial with either a parallel or cross-over design
  2. Must have a treatment period of at least 4 week.
  3. Healthy children and adults, overweight and obese individuals or individuals with diabetes were all acceptable
  4. Must have one of the selected viscous fibres, (agar, alginate, β-glucan, guar gum, pectin, polyglycoplex(PGX), Psyllium, Xanthan), as a supplemented treatment.
  5. Only β-glucan sources from barley or oat were accepted The amount of barley product or barley β-glucan must be reported or measured, or must be computable. β-glucan was considered to be 4.75% in barley, and 3-5% in oat.
  6. Must be appropriately controlled.
  7. Must measure one of outcomes: body weight, BMI, waist circumference, or Body fat percentage.
  8. These Anthropometry measures can be either primary or secondary outcomes.
  9. Enough information must be provided to calculate the magnitude of effect, i.e. end of treatment measures and/or change from baseline measures
  10. Ad lipitum diet only.

Exclusion Criteria:

  1. If the soluble fibre was not one of the selected viscous fibre or a combination.
  2. supplement where these fibers could not be isolated each one alone.
  3. If the study was insufficiently controlled, i.e. the control was another soluble fibre.
  4. If the outcome measures did not include body weight, BMI, waist circumference, or Body fat percentage.
  5. If the intervention was a diet with no supplemented fibre.
  6. If the study provided insufficient information to calculate a magnitude of effect
  7. If the study protocol maintains baseline weight.
  8. Secondary information such as reviews, editorials, commentaries, were excluded
  9. If the diet is hypo-caloric, energy restricted diet, or metabolically controlled diet.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Other
  • Time Perspectives: Prospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Body weight chang
Time Frame: in 4 weeks or more
unit of measure: Kg
in 4 weeks or more
BMI change
Time Frame: in 4 weeks or more
unit of measure: Kg/m2
in 4 weeks or more
Waist circumference change
Time Frame: in 4 weeks or more
unit of measure: Cm
in 4 weeks or more
Body fat percentage change
Time Frame: in 4 weeks or more
unit of measure: %
in 4 weeks or more

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Unity Health Toronto

Investigators

  • Study Director: Nourah Mazhar, MSc (C), St.Michael Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

March 1, 2016

Primary Completion (Anticipated)

November 1, 2017

Study Completion (Anticipated)

November 1, 2017

Study Registration Dates

First Submitted

August 17, 2017

First Submitted That Met QC Criteria

August 17, 2017

First Posted (Actual)

August 22, 2017

Study Record Updates

Last Update Posted (Actual)

August 22, 2017

Last Update Submitted That Met QC Criteria

August 17, 2017

Last Verified

August 1, 2017

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Body Weight Loss Meta

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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