Role of Slowly Digesible Starch on Diabetes Risk Factors

Study Overview
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Brief Summary
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The purpose of this study is to determine the effect of a slowly digesting starch on gut bacteria, sugar and fat metabolism, hunger hormones, and body fat in people with pre-diabetes.

Detailed Description
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In a double blind randomized controlled clinical trial, the investigators will test the effect of slowly digesting starch (amylose) versus a placebo starch (amylopectin) on risk factors for type 2 diabetes. For the study, about 95 obese participants (ages 35-65) with pre-diabetes (impaired fasting glucose) will consume a yogurt containing about 45 g of either the experimental or placebo starch daily for 3 months. The investigators will test the hypothesis that, compared to controls, a daily intake of 45 g of amylose for 3 months will improve risk factors for the development of type 2 diabetes (insulin sensitivity and secretion) by decreasing ectopic fat depots and decreasing inflammation in parallel with a change in colonic microbial populations.

Official Title
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Role of Slowly Digesible Starch on Diabetes Risk Factors In Pre-diabetic People

Conditions
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Prediabetes

Intervention / Treatment
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* Dietary Supplement: Amylose
* Dietary Supplement: Amylopectin


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria Have a body mass index between 30 and 44.9 kg/m2 Are 35-65 years of age Have pre-diabetes, which means impaired fasting glucose (IFG) Are willing to complete nutritional and activity questionnaires and 2-3 weeks of baseline testing Are willing to enroll in the 3-month intervention and maintain the same level of exercise during the study Are willing to maintain weight throughout the study Exclusion Criteria Have evidence of cardiovascular disease, diabetes, symptomatic cholelithiasis (gallstones), or cancer Have a fasting blood glucose less than 100 mg/dL or greater than 125 mg/dL Have an average screening blood pressure > 150/100 mm Hg Are a pre-menopausal woman but do not have a regular menstrual cycle Are pregnant or breastfeeding Chronically use medications including diuretics, steroids, and adrenergic-stimulating agents Have emotional problems such as clinical depression or other diagnosed psychological conditions Use hormonal contraceptives, oral or parenteral glucocorticoids, or any other medication known to influence glucose or insulin homeostasis (balance), within 1 month of study Have a clinically significant gastrointestinal malabsorption syndrome, chronic diarrhea, or use antibiotics within one month of study Have abnormal laboratory markers (e.g., elevated potassium levels, hemoglobin or hematocrit below the lower limit of normal) Chronically consume alcohol (> 4 servings per day) or actively smoke cigarettes (> 1/4 pack per day) Are on any chronic medication that has not had a stable dose for 1 month or longer Are required to perform of any kind of heavy physical activity Have metal objects in the body, such as a pacemaker, metal pins, bullet, etc.

Ages Eligible for Study
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Minimum Age: 35 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Placebo Starch<br>Yogurt with about 45 g/day of placebo starch (amylopectin). | Dietary Supplement: Amylose<br>* One group of participants will consume a yogurt containing 45 g of amylose (the slowly digesting starch) for 3 months.<br>|
| Experimental: Experimental Starch<br>Yogurt with about 45 g/day of slowly digestible starch (amylose). | Dietary Supplement: Amylopectin<br>* The second group will consume a yogurt containing 45 g of a different starch called amylopectin (the placebo) for 3 months.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Insulin Sensitivity and Secretion | Insulin sensitivity and secretion will be assessed via a Frequently Sampled Intravenous Glucose Tolerance Test (FSIGTT). | 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Body Composition | DXA and MRS will be performed to measure body composition (adipose, muscle, bone mineral content) and to measure hepatic and intramyocellular lipids, respectively. | 3 months | 
| Gut Microbiota | Stool samples will be collected and fecal bacteria diversity will be measured in conjunction with metagenomic analysis. | 3 months | 
| Satiety | Satiety hormones will be measured following ingestion of a standardized smoothie (Standard Meal Test). Satiety will be measured through visual analogue scales (VAS), remote food photography, and a food intake test. | 3 months | 
| Hunger | Hunger will be measured through visual analogue scales (VAS), remote food photography, and a food intake test. | 3 months |