Diabetes mellitus, particularly type 1 diabetes, is characterized by hyperglycemia due to defects in insulin secretion or action. Intensive insulin therapy is the recommended treatment, aiming to maintain blood glucose levels similar to those in healthy individuals. Carbohydrates significantly influence glycemic response, and rice is a common carbohydrate source for many, including diabetic patients. Starch, the main carbohydrate in rice, undergoes gelatinization during cooking, increasing digestibility. However, cooling cooked rice leads to starch retrogradation, forming resistant starch which resists digestion in the small intestine. This study aimed to determine whether cooling rice affects postprandial glycemia in type 1 diabetes patients, evaluating the impact on hypoglycemic episodes, hunger, satiety, and organoleptic properties.

Existing literature highlights the significant impact of carbohydrates on glycemic response. Rice, a major dietary staple, contains starch consisting of amylose and amylopectin. Heating (gelatinization) increases starch digestibility, while cooling causes retrogradation, leading to resistant starch formation. Resistant starch resists enzymatic degradation, potentially lowering postprandial glucose levels. However, prior research on the effect of retrograded starch on postprandial glycemia in type 1 diabetes patients was lacking, necessitating this study to assess this relationship and its potential for improving metabolic control.

A randomized, single-blind crossover study involved 32 type 1 diabetes patients on intensive insulin pump therapy. Participants consumed two standardized meals containing 50g of carbohydrates: one with freshly cooked long-grain white rice and another with rice cooled for 24 hours at 4°C and reheated. Postprandial glycemia was monitored for 3 hours using the FreeStyle Libre flash glucose monitoring system. Insulin boluses were administered based on carbohydrate content, correction factor, and insulin sensitivity factor. Data on hypoglycemic episodes, organoleptic evaluation, hunger, satiety, and desire to eat were also collected. Statistical analysis included paired t-tests and Wilcoxon signed-rank tests.

Compared to fresh rice, cooled rice resulted in significantly lower: * Maximum glycemia [9.9 (9.4-10.9) mmol/L vs. 11 (10.3-11.7) mmol/L, p=0.0056] * Maximum glycemic increase [2.7 (1.5-3.6) mmol/L vs. 3.9 (2.5-4.7) mmol/L, p<0.0001] * Area under the glycemic curve [135 (34.3-283.9) mmol/L*180 min vs. 336 (123.9-486.9) mmol/L*180 min, p<0.0001] * Time to peak glycemia [35 (28-43) min vs. 45 (35-55) min, p=0.031] There was no significant difference in insulin dose between the two groups. However, the number of hypoglycemic episodes was significantly higher after consuming cooled rice (12 vs. 3, p=0.0039). Organoleptic assessment and hunger/satiety scores showed no significant differences between the two meals.

This study provides novel evidence of the beneficial effect of cooling pre-cooked rice on postprandial glucose control in type 1 diabetes. The reduction in postprandial glycemia is attributed to the increased resistant starch content during cooling. The shorter time to peak glycemia with cooled rice may better align with the peak action of short-acting insulin analogs. Although prior research in healthy individuals or type 2 diabetes patients showed similar results regarding glycemic reduction, this study uniquely demonstrates the effect in type 1 diabetes patients without endogenous insulin. The increased risk of hypoglycemia highlights the need for insulin dose adjustments when consuming cooled rice. This finding emphasizes the importance of individualized dietary management in diabetes.

Cooling rice significantly reduces postprandial blood glucose in type 1 diabetes patients, but also increases the risk of hypoglycemia if the insulin dose isn't adjusted. Organoleptic properties and appetite are unaffected by the cooling process. Future research should focus on determining optimal insulin dose reductions for cooled rice to minimize hypoglycemia risk and further explore the impact of multiple cooling/heating cycles on resistant starch content and glycemic response. These findings highlight the potential for modifying food preparation methods to improve glycemic control.

The study's relatively small sample size might limit the generalizability of the findings. The FreeStyle Libre system, while convenient, offers continuous glucose monitoring which might inadvertently unblind some participants to the type of rice consumed, influencing the outcome. Future studies should consider using blinded continuous glucose monitoring systems for more robust results. The single cooling and reheating cycle might not reflect real-world practices.