Effect of Dietary Glycemic Index on Beta-cell Function

• Status: Completed
• Trial end date: 2019-08-01
• Target enrollment: 0
• Participant gender: All

Summary

The study will determine if increasing the highs and lows of blood glucose levels (glycemic variability) impairs insulin secretion in people with impaired glucose tolerance and/or impaired fasting glucose who are at risk for developing type 2 diabetes. Furthermore, the study will determine whether changes in beta-cell function are associated with glycemic variability and whether they are mediated by oxidative stress. To decrease or increase glycemic variability the study will provide subjects with special diets containing either low or high glycemic index foods respectively for 4 weeks. To determine if oxidative stress is a mediator, subjects on the high glycemic index diet will take either placebo or the anti-oxidant N-acetylcysteine. The study will address the hypothesis that increased glycemic variability results in increased oxidative stress and thereby exacerbates beta-cell dysfunction in individuals with impaired glucose tolerance and/or impaired fasting glucose. The findings may have important implications for the development of effective strategies aimed at the prevention and treatment of type 2 diabetes. In addition, understanding the contribution of dietary glycemic index to beta-cell dysfunction in subjects with pre-diabetes may have a significant public health impact, including changes to dietary counseling and promotion of healthier eating patterns.

• Phase: N/A
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: Seattle Institute for Biomedical and Clinical Research
• Collaborator: VA Puget Sound Health Care System
• Treatments: Acetylcysteine; N-monoacetylcystine

Criteria

Inclusion Criteria:

• impaired glucose tolerance (2 hour glucose 140-200 mg/dl after a standard 75 grams oral glucose tolerance test [OGTT]) or

• fasting glucose 100-115 mg/dl and 2 hour glucose > 100 mg/dl after a standard OGTT

Exclusion Criteria:

• diabetes or taking diabetes medications

• fasting glucose >115 mg/dl

• alanine aminotransferase (ALT) >1.5 times the upper limit of normal

• hematocrit <33%

• serum creatinine >1.5 men or >1.3 women

• multiple food allergies or intolerances

• other serious medical or inflammatory conditions

• pregnancy or lactation

• smoke or use tobacco

• take medications that affect insulin sensitivity and secretion (niacin, diabetes medications or glucocorticoids) or inflammation (anti-inflammatories such as ibuprofen, naprosyn, aspirin)

• significant gastroesophageal reflux (heartburn), swallowing problems or stomach ulcers, including those taking medication for these indications

• taking or having taken another investigational drug within the past 30 days