Beta-glucan and Insulin Sensitivity in Obese Humans

The Influence of Beta-glucan 1.3D-1.6D, Added to the Low-calorie Diet, on Insulin Sensitivity and the Expression of Selected Proinflammatory Cytokines in Adipose Tissue and Peripheral Blood Mononuclear Cells in Obese Humans

Obesity is an important health problem of modern civilization. In Western societies, almost half of the adult population has problems with an increased body weight. Products containing nutritional fiber has been used by humans for thousands of years. However, beta-glucan as biologically active compound, present in these products, has been identified relatively lately. This substance is a polymer of glucose and is present in two forms: 1,3D-1,6D and 1,3D-1,4D.

Water-insoluble beta-glucan (1,3D-1,6D) has immunomodulatory properties. The aim of the study was the assessment of the influence of beta-glucan 1,3D-1,6D added to the low-calorie diet on insulin sensitivity and the expression of selected proinflammatory cytokines in adipose tissue and peripheral blood mononuclear cells (PBMC) in obese humans with normal glucose tolerance.

The study group consisted of 40 subjects with marked overweight or obesity (body mass index, BMI > 28 kg/m2), without serious concomitant diseases not taking drugs affecting glucose or lipid metabolism, nonsmokers. Only volunteers, who gave written informed consent, after receiving a full information about the aim and the design of the study, were recruited.

At the beginning of the study, after subjects' qualification to the project and before the dietary intervention, the investigators performed:

• anthropometric measurements.
• oral glucose tolerance test.
• euglycemic hyperinsulinemic clamp.
• PBMC isolation before and after the clamp.
• biopsy of subcutaneous adipose tissue before the clamp.
• isolation of mRNA from PBMC and adipose tissue. Then, the expression of the selected genes with the Real Time PCR was measured.
• After the initial visit, participants received detailed instructions about low-calorie diet, with the aim of reduction of 5-7% of body weight and the examples of menu for 14 days.

Then, participants were randomly assigned to a group receiving or not beta-glucan preparation, as a addition to the low-calorie diet. Each group consisted of 20 subjects. Subjects assigned to a group receiving beta-glucan, received the preparation (BETA GLUCAN 1,3-1,6 Laboratoria Natury 500mg) together with the detailed instruction of its usage. This preparation is used as a non-prescription diet supplement, and the dose of 500 mg daily is indicated by the manufacturer.

After 12 weeks of low-calorie diet, without or with beta-glucan, all the examinations performed at the beginning of the study were repeated.

Study Overview

• Status: Completed
• Conditions: Obesity
• Intervention / Treatment: Other: low-calorie diet; Dietary supplement: low calorie diet plus beta-glucan

Detailed Description

Obesity is an important health problem of modern civilization. In Western societies, almost half of the adult population has problems with an increased body weight. In Europe, obesity occurs in 10-20% males and 15-25% females. In Poland, obesity is present in about 20% of population.

Products containing nutritional fiber has been used by humans for thousands of years. However, beta-glucan as biologically active compound, present in these products, has been identified relatively lately. This substance is a polymer of glucose and is present in two forms: 1,3D-1,6D and 1,3D-1,4D.

Water-insoluble beta-glucan (1,3D-1,6D) has immunomodulatory properties. It stimulates host defense against viral, bacterial and parasitical infections through binding with the specific receptors located on the immune system cells surface in many animal models. There are data that beta-glucan 1,3D-1,6D affects both innate and acquired immune response also in humans.

The aim of the study was the assessment of the influence of beta-glucan 1,3D-1,6D added to the low-calorie diet on insulin sensitivity and the expression of selected proinflammatory cytokines in adipose tissue and peripheral blood mononuclear cells (PBMC) in obese humans with normal glucose tolerance.

The study group consisted of 40 subjects with marked overweight or obesity (body mass index, BMI > 28 kg/m2), without serious concomitant diseases not taking drugs affecting glucose or lipid metabolism, nonsmokers. Only volunteers, who gave written informed consent, after receiving a full information about the aim and the design of the study by the research personnel were recruited.

At the beginning of the study, after subjects' qualification to the project and before the dietary intervention, the investigators assessed:

• anthropometric measurements: BMI, waist-to-hip ratio (WHR), full physical examination.
• body composition with Tanita TBF-511 Body Fat Analyzer.
• glucose tolerance with the oral glucose tolerance test.
• insulin sensitivity with the euglycemic hyperinsulinemic clamp technique.
• before and after the clamp, additional 6 ml of blood was collected, and PBMC isolation was performed.
• before the clamp, a biopsy of subcutaneous adipose tissue was performed.
• isolation of mRNA from PBMC and adipose tissue was performed. Then, the expression of the selected genes with the Real Time PCR In adipose tissue was measured measured.
• additionally, serum concentrations of ghrelin, peptide Y-Y3-36, citruline and intestinal fatty acid-binding protein was assessed.

After the initial visit, participants received detailed instructions about low-calorie diet, with the aim of reduction of 5-7% of body weight and the examples of menu for 14 days.

Then, participants were randomly assigned to a group receiving or not beta-glucan preparation, as a addition to the low-calorie diet. Each group consisted of 20 subjects. Subjects assigned to a group receiving beta-glucan, received the preparation (BETA GLUCAN 1,3-1,6 Laboratoria Natury 500mg) together with the detailed instruction of its usage. This preparation is used as a non-prescription diet supplement, and the dose of 500 mg daily is indicated by the manufacturer.

Analysis of the compliance to the dietary indications and analysis of body composition was performed every 2 weeks.

After 12 weeks of low-calorie diet, without or with beta-glucan, all the examinations performed at the beginning of the study were repeated.

• Study Type: Interventional
• Enrollment (Actual): 40
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Poland
  • Olsztyn, Poland, 10-748
    • Institute of Animal Reproduction and Food Research, Polish Academy of Sciences

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years to 50 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• marked overweight or obesity (BMI above 28 kg/m2)
• normal glucose tolerance

Exclusion Criteria:

• morbid obesity (BMI above 40 kg/m2)
• impaired glucose tolerance or diabetes
• cardiovascular diseases
• other serious disease
• smoking
• usage of drugs known to affect carbohydrate or lipid metabolism

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: low-calorie diet; Intervention was low-calorie diet only for 12 weeks.	Other: low-calorie diet; low-calorie diet only for 12 weeks.
Active Comparator: low calorie diet plus beta-glucan; Intervention was low-calorie diet plus BETA-GlLUCAN 1.3D-1.6D 500 mg daily for 12 weeks.	Other: low-calorie diet; low-calorie diet only for 12 weeks.; Dietary supplement: low calorie diet plus beta-glucan; beta-glucan 1.3D-1.6D, together with a low calorie diet, 500 mg once daily for 12 weeks

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
insulin sensitivity	one year

Secondary Outcome Measures

Outcome Measure	Time Frame
body weight	one year
amount of visceral adipose tissue	one year
expression of selected genes in PBMC and adipose tissue	one year

Collaborators and Investigators

• Sponsor: Marek Straczkowski
• Investigators: Principal Investigator: Marek Straczkowski, MD, prof., Institute of Animal Reproduction and Food Research, Polish Academy of Sciences

Study record dates

Study Major Dates

• Study Start: May 1, 2011
• Primary Completion (Actual): August 1, 2015
• Study Completion (Actual): August 1, 2015

Study Registration Dates

• First Submitted: July 12, 2011
• First Submitted That Met QC Criteria: July 12, 2011
• First Posted (Estimate): July 13, 2011

Study Record Updates

• Last Update Posted (Estimate): March 30, 2016
• Last Update Submitted That Met QC Criteria: March 29, 2016
• Last Verified: March 1, 2016

More Information

Terms related to this study

• Keywords: insulin sensitivity; inflammation; adipose tissue
• Additional Relevant MeSH Terms: Glucose Metabolism Disorders; Metabolic Diseases; Immune System Diseases; Hyperinsulinism; Hypersensitivity; Insulin Resistance
• Other Study ID Numbers: ZPChM-11-01

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO