Protein Intake & Insulin Action

This study is currently recruiting participants. (see Contacts and Locations)
Verified December 2013 by Washington University School of Medicine
Sponsor:
Information provided by (Responsible Party):
Washington University School of Medicine
ClinicalTrials.gov Identifier:
NCT02004002
First received: December 2, 2013
Last updated: December 5, 2013
Last verified: December 2013
  Purpose

The purpose of this proposal is to determine whether dietary protein restriction has beneficial effects on skeletal muscle insulin sensitivity and β-cell function in obese men and women.


Condition Intervention
Obesity
Behavioral: Weight maintenance with normal protein intake
Behavioral: Weight maintenance with protein restriction

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: Dietary Protein Intake, Insulin Sensitivity and β-cell Function

Resource links provided by NLM:


Further study details as provided by Washington University School of Medicine:

Primary Outcome Measures:
  • Insulin sensitivity [ Time Frame: up to 8 wk dietary intervention ] [ Designated as safety issue: No ]
    We will evaluate insulin sensitivity using the hyperinsulinemic-euglycemic clamp procedure in conjunction with stable isotope labeled tracer infusions.

  • total β-cell sensitivity index (Φtotal) [ Time Frame: Before and after the 8 wk dietary intervention ] [ Designated as safety issue: No ]
    The total β-cell sensitivity index assesses the insulin secretion response to changes in plasma glucose concentration following ingestion of a glucose drink.


Secondary Outcome Measures:
  • Disposition index [ Time Frame: Before and after the 8 wk dietary intervention ] [ Designated as safety issue: No ]
    The disposition index provides an assessment of insulin secretion in relationship to insulin sensitivity to determine whether insulin secretion was "appropriate" for the degree of insulin sensitivity.


Estimated Enrollment: 30
Study Start Date: December 2013
Estimated Study Completion Date: December 2016
Estimated Primary Completion Date: July 2016 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: Weight maintenance with normal protein intake
Control group will consume 1.4 g protein/kg body wt/d; consistent with the average protein intake in the US population.
Behavioral: Weight maintenance with normal protein intake
Control group will consume 1.4 g/kg/d of protein; consistent with the average protein intake in the US population.
Experimental: Weight maintenance with protein restriction
Protein restriction group will receive the Institute of Medicine RDA of 0.8 g protein/kg body wt/d.
Behavioral: Weight maintenance with protein restriction
Protein restriction group will receive the Institute of Medicine RDA of 0.8 g protein/kg body wt/d.

Detailed Description:

Insulin resistance, impaired pancreatic β-cell function, and diabetes are important complications associated with obesity. Although excess energy intake and body fat accumulation are considered the major culprits responsible for obesity-associated metabolic abnormalities, it is possible that insulin resistance and impaired β-cell function are also due to increased dietary protein intake.

Protein intake is ~15 to 25% greater in obese than lean adults and exceeds the current Institute of Medicine Recommended Daily Allowance (RDA) of 0.8 g protein/kg body weight by ~75%. An increase in habitual protein intake of only 10 to 40%, assessed using dietary recall methods, been shown to increase the risk of developing diabetes by up to 2.2 fold. Additionally, the ability to stimulate glucose disposal during insulin infusion is reported to be impaired in individuals consuming double the recommended protein intake as part of an isoenergetic diet. However, it is not known whether decreasing protein intake can improve insulin sensitivity and β-cell function in weight-stable, obese individuals.

Accordingly, obese men and women will be randomized to 8 weeks of treatment with a weight maintaining diet containing either i) 0.8 g protein/kg body weight (as recommended by the Institute of Medicine; protein restriction group)or ii) 1.4 g protein/kg body weight (control group). All subjects will receive a standardized "base-diet" with or without protein supplementation to avoid potential food selection bias that could confound the results when using high- and low-protein diets.

  Eligibility

Ages Eligible for Study:   18 Years to 65 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Body mass index (BMI) between 30 and 50 kg/m2
  • Subjects who are sedentary (<1.5 h of exercise/week)

Exclusion Criteria:

  • Subjects with evidence of significant organ system dysfunction (e.g. diabetes, severe cardiovascular disease, hyperlipidemia, cirrhosis, hypogonadism, uncontrolled hypo- or hyperthyroidism; uncontrolled hypertension)
  • Subjects with metal implants
  • Individuals with cancer or cancer that has been in remission for <5 years,
  • Individuals with dementia,
  • Individuals who use tobacco products,
  • Subjects who are taking medications known to affect glucose metabolism (e.g., steroids),
  • Subjects taking medications to control certain medical conditions (e.g., hypertension) will be included if the drug regimen has been stable for at least 6 months before entering the study and is not expected to change during the study.
  • Women who are pregnant due to changes in body composition and decreases in insulin sensitivity caused by pregnancy
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT02004002

Contacts
Contact: Lynda Bowers 314-362-0590 lbowers@dom.wustl.edu

Locations
United States, Missouri
Washington University School of Medicine Recruiting
St Louis, Missouri, United States, 63110
Sponsors and Collaborators
Washington University School of Medicine
Investigators
Principal Investigator: Gordon Smith, PhD Washington University School of Medicine
  More Information

No publications provided

Responsible Party: Washington University School of Medicine
ClinicalTrials.gov Identifier: NCT02004002     History of Changes
Other Study ID Numbers: WSP-201303080
Study First Received: December 2, 2013
Last Updated: December 5, 2013
Health Authority: United States: Institutional Review Board

Additional relevant MeSH terms:
Obesity
Insulin Resistance
Overnutrition
Nutrition Disorders
Overweight
Body Weight
Signs and Symptoms
Hyperinsulinism
Glucose Metabolism Disorders
Metabolic Diseases

ClinicalTrials.gov processed this record on August 28, 2014