Dietary Protein and Insulin Sensitivity Study

Sponsor

UCSF Benioff Children's Hospital Oakland (Other)

Overall Status

Completed

CT.gov ID

NCT00508937

Collaborator

Dairy Management Inc. (Industry)

660

Enrollment

Locations

Arms

Duration (Months)

330

Patients Per Site

9.7

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

The overall objective of the Dietary Protein and Insulin Sensitivity Study is to test the hypothesis that increased protein in a diet with reduced carbohydrate (35% energy) can ameliorate insulin resistance in the absence of weight loss, and that this effect is independent of saturated fat content. Moreover, we will test whether such diets result in beneficial changes in total LDL cholesterol, small, dense LDL, and HDL cholesterol that are also independent of saturated fat intake.

Condition or Disease	Intervention/Treatment	Phase
Insulin Resistance Type 2 Diabetes Metabolic Syndrome Cardiovascular Disease Dyslipidemia	Other: Diet Other: Diet Other: Diet Other: Diet Other: Diet	N/A

Detailed Description

Insulin resistance is a major metabolic disturbance associated with excess adiposity that contributes to atherogenic dyslipidemia and predisposes to both cardiovascular disease and type 2 diabetes mellitus. The effects on insulin resistance of changes in dietary macronutrient composition in the absence of weight loss are poorly understood. To better understand these effects, we will study men and women with insulin resistance after 4 weeks on a basal diet (15% protein, 55% carbohydrate, 30% fat) and 4 weeks after random assignment to the basal diet or one of 4 diets with 35% carbohydrate and either 20% or 30% protein, and either 7% or 15% saturated fat. At the end of each dietary period (4 weeks and 8 weeks), we will draw a blood sample for detailed metabolic measurements and measure insulin sensitivity by the frequently sampled intravenous glucose tolerance test (FSIGT) method. In addition to insulin resistance, we will assess the effect of dietary composition on parameters of atherogenic dyslipidemia.

Study Design

Study Type:

Interventional

Actual Enrollment :

660 participants

Allocation:

Randomized

Intervention Model:

Parallel Assignment

Masking:

Single (Investigator)

Primary Purpose:

Prevention

Official Title:

The Effects of Increased Dietary Protein Intake on Insulin Sensitivity in Stable Weight Individuals, Independent of Dietary Content of Carbohydrate and Saturated Fat

Study Start Date :

Feb 1, 2007

Actual Primary Completion Date :

Nov 1, 2009

Actual Study Completion Date :

Dec 1, 2009

Arms and Interventions

Arm	Intervention/Treatment
Active Comparator: 1	Other: Diet 15% protein, 55% carbohydrate, 30% fat (7% saturated, 7% polyunsaturated)
Experimental: 2	Other: Diet 20% protein, 35% carbohydrate, 45% fat (7% saturated, 7% polyunsaturated)
Experimental: 3	Other: Diet 20% protein, 35% carbohydrate, 45% fat (15% saturated, 7% polyunsaturated)
Experimental: 4	Other: Diet 30% protein, 35% carbohydrate, 35% fat (7% saturated, 7% polyunsaturated)
Experimental: 5	Other: Diet 30% protein, 35% carbohydrate, 35% fat (15% saturated, 7% polyunsaturated)

Outcome Measures

Primary Outcome Measures

Insulin Sensitivity by Frequently Sampled Intravenous Glucose Tolerance test [4wks and 8wks]
Total Cholesterol [4wks and 8wks]
LDL Cholesterol [4wks and 8wks]
HDL Cholesterol [4wks and 8wks]
Triglycerides [4wks and 8wks]
LDL peak particle size [4wks and 8wks]
LDL subclasses [4wks and 8wks]

Secondary Outcome Measures

Apolipoprotein B [4wks and 8wks]
Apolipoprotein A1 [4wks and 8wks]

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years and Older

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Yes

Inclusion Criteria:

Body mass index (BMI) ≥ 27 and ≤ 40 kg/m2
HOMA-IR ≥ 2.5
Non-smoking
Total cholesterol and LDL cholesterol <95th percentile for sex and age
Fasting triglycerides < 500mg/dl
Fasting blood sugar < 126
Urinary microalbumin < 30 mg/L
Normal thyroid stimulating hormone levels
Hematocrit ≥ 36%
Blood pressure < 150/90
At least 3 months of a weight-stable state (± 5 lbs) prior to the study. During the study, subjects will be required to maintain their body weight within ± 3% (up to a maximum change of 5 lbs) of their initial weight over the course of any consecutive two weeks after the second week of baseline diet or during the last week of each diet phase

Exclusion Criteria:

History of coronary heart disease, cerebrovascular disease, peripheral vascular disease, bleeding disorder, liver or renal disease, diabetes, lung disease, HIV, or cancer (other than skin cancer) in the last 5 years
Use of drugs known to affect lipid metabolism or insulin resistance, hormones, or the blood thinning agent, warfarin
Use of alcohol or dietary supplements during the study
Pregnancy