NCT04507685

Asian Indian Prediabetes Study

Diet and Lifestyle Intervention Strategies to Treat β-cell Dysfunction and Insulin Resistance in Asian Indians

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 53 (actual)
• Sponsor: Institute for Human Development and Potential (IHDP), Singapore · Academic / Other
• Sex: All
• Age: 21 Years – 50 Years
• Healthy volunteers: Accepted

Summary

Compared to other races, Indians have higher insulin resistance, poorer pancreatic function and a greater risk of developing diabetes, highlighting the importance of early strategies for improving insulin sensitivity and improving pancreatic function in Indians to prevent diabetes and lower the risk of heart disease. A low carbohydrate diet can deplete fat from undesirable places, such as fat around organs in the abdominal cavity. In this study, we will determine if restriction of dietary carbohydrates will deplete fat in the pancreas and liver, and improve insulin sensitivity and early insulin secretion in Indians. These changes may prevent diabetes from developing. Hepatic and pancreatic fat will be measured using magnetic resonance imaging. Insulin sensitivity and secretion will be measured during an oral glucose tolerance test. In addition, this study will investigate if the higher insulin resistance in Indians is due to genes that cause the inability to store fat in the legs. The results on the type of diet that is more effective for reducing pancreatic and hepatic fat is important for informing dietary guidelines on the use of low carbohydrate diets for diabetes prevention, particularly in Indians who have a higher risk of developing diabetes.

Detailed description

Compared to other races, Indians have a greater risk of developing type 2 diabetes (T2D), increased insulin resistance (IR) and more rapid decline in β-cell function, highlighting the urgency and importance of early intervention strategies for improving insulin sensitivity and preserving/improving β-cell function to prevent T2D and mitigate against the increased vascular disease risk. Preliminary findings show a reduction in glycemic load selectively depletes visceral and ectopic lipid and improves insulin sensitivity and β-cell function in non-diabetic adults. The proposed research will investigate if the phenotypic features increasing T2D risk in individuals of Indian ancestry (IR and impaired β-cell function) can be favorably modified by a low glycemic (LG) intervention, and if the increased IR is attributable to genetic factors regulating adipocyte differentiation and function. These research objectives will be achieved through a 24-week randomized controlled trial (RCT) comparing isocaloric LG versus control diets in Indians with prediabetes. Compared to individuals in the control group, those on the LG diet are expected to have greater ectopic (pancreas, liver, visceral and intramyocellular) fat depletion assessed with MRI/MRS, and improvements in first phase insulin secretion and insulin sensitivity assessed with the C-peptide model and oral minimal model, respectively during an OGTT. Reductions in hepatic and pancreatic lipids will be associated with improvements in first-phase β-cell response. Individuals with a greater number of risk alleles from a 53-SNP IR genetic risk score will have lower insulin sensitivity and leg fat, supporting the notion that impaired adipocyte differentiation leading to limited peripheral adipose expansion capacity is an important etiological factor underpinning IR cardiometabolic disease in Indians. The results will broaden the evidence base for effective prevention strategies in this high risk population by investigating the effect of the proposed diet intervention on underlying physiological and molecular mechanisms implicated in the pathophysiology of T2D in Indians.

Conditions

• Pre Diabetes

Interventions

Type	Name	Description
OTHER	Lifestyle (Diet and Exercise)	The LG diet will comprise 20% carbohydrate, 30% protein, and 50% fat (\<10% saturated fat). It will have a low glycaemic load; include plant and animal protein; non-starchy vegetables and salad greens; and some low-sugar fruit. Participants will be encouraged to incorporate a variety of foods rich in monounsaturated and polyunsaturated fats in their diet. The control diet will comprise 50% carbohydrate, 20% protein and 30% total fat (\<10% saturated fat). It will reflect the Health Promotion Board's (HPB) recommendations to reduce dietary fat, emphasize wholegrains and include a variety of fruits and vegetables. In contrast to the LG diet, the control diet will have a higher glycaemic load with a greater proportion of energy derived from unrefined carbohydrate foods. Concurrent to the dietary intervention and consistent with physical activity guidelines, all participants will undertake a 60-min structured exercise program incorporating aerobic/ resistance exercises 3-4 days/week.

Timeline

• Start date: 2020-10-19
• Primary completion: 2023-01-27
• Completion: 2023-02-01
• First posted: 2020-08-11
• Last updated: 2023-11-22

Locations

1 site across 1 country: Singapore