The Effect of Substituting White Rice With Sorghum Rice on Pancreatic Beta-Cell Function and Insulin Resistance in Prediabetes

This open-label randomized pre-post experimental study was designed to evaluate the metabolic effects of short-term sorghum rice consumption on serum leptin levels in prediabetic individuals. The study was conducted over a two-month period (March to April 2022) at the Bojonegoro Police Polyclinic and Bojonegoro Bhayangkara Hospital in East Java, Indonesia.

Rationale and Background The study addresses a critical gap in understanding dietary interventions for prediabetes management in Indonesia, where white rice consumption is a dominant dietary pattern associated with increased type 2 diabetes risk. Sorghum (Sorghum bicolor L.) represents a promising functional whole grain alternative, containing high levels of dietary fiber, resistant starch, and phenolic compounds with antioxidant properties. These bioactive components may influence adipokine profiles, particularly leptin, an adipocyte-derived hormone that plays a central role in energy homeostasis and is frequently dysregulated in prediabetic states. The study specifically targeted police officers, a population with unique physical activity patterns and occupational stress factors that may influence metabolic responses.

Twenty-six prediabetic participants were recruited through simple random sampling and randomly assigned in a 1:1 ratio to either the intervention (sorghum rice) group or the control (white rice) group, with 13 participants in each arm. The sample size was calculated using a standard formula for comparing numerical data between two independent groups, accounting for expected differences in leptin levels based on preliminary data and published literature. Randomization was performed to minimize selection bias and ensure comparable baseline characteristics between groups.

Participants in the intervention group completely substituted their regular white rice intake with sorghum rice for seven consecutive days. The sorghum rice was prepared according to standardized cooking procedures supervised by a registered dietitian to ensure consistency in preparation methods and palatability. The daily amount of sorghum or white rice consumed was individually calculated based on each participant's total daily energy requirements, determined using standard anthropometric measurements and physical activity assessments. This personalized approach ensured that participants maintained their usual caloric intake while only varying the grain type consumed.

The control group continued their habitual white rice consumption throughout the study period. Both groups received identical standardized lifestyle education sessions focusing on balanced nutrition principles and the importance of regular physical activity in prediabetes management, ensuring that any observed differences could be attributed to the grain substitution rather than differential educational interventions.