Effect of Proso Millet-Based Bread on Postprandial Glycemic Response in Adults With Type 2 Diabetes

This is a randomized, double-blind, two-period crossover clinical study designed to evaluate the acute postprandial glycemic response to proso millet-based bread compared with white wheat bread in adults with type 2 diabetes.

Prior to the clinical phase, different proso millet-based bread formulations will be evaluated for sensory and physical characteristics. The formulation with the highest overall acceptability and appropriate structural characteristics will be selected as the investigational bread for the clinical phase. Texture profile analysis will be performed for quality-control purposes on the selected proso millet-based bread and the white wheat bread.

In the clinical phase, participants will undergo two test sessions in randomized order. Each participant will receive both interventions and therefore serve as their own control. The two sessions will be separated by a one-week washout period.

The investigational intervention will consist of the selected proso millet-based bread, and the comparator intervention will consist of white wheat bread. Portions will be standardized to provide 50 g of available carbohydrate, calculated as total carbohydrate minus dietary fiber. Test products will be presented using coded identifiers to maintain blinding of participants and investigators.

At each test session, participants will consume the assigned bread within 10 minutes together with 250 mL of water. Timing will begin with the first bite. Capillary blood glucose will be measured at 0, 15, 30, 45, 60, 90, 120, 150, and 180 minutes. Postprandial glucose response will be evaluated using the incremental area under the glucose response curve calculated by the trapezoidal method.

Before the test sessions, participant characteristics, health information, dietary habits, physical activity, dietary intake, anthropometric measurements, and body composition will be assessed. These data will be used to characterize the study population and support the evaluation of the clinical findings.

Inclusion criteria

• Age between 35 and 60 years Body mass index (BMI) ≥18.5 and ≤39.99 kg/m² Diagnosed with type 2 diabetes mellitus for at least 1 year Stable doses of antidiabetic medications for at least 3 months Cognitively capable of following dietary records and study instructions

Exclusion criteria

• Presence of atherosclerotic cardiovascular disease Malignancy Gastrointestinal disease Psychiatric disease Use of vitamin, mineral, or nutritional supplements Food allergy Following a weight-loss diet within the previous 3 months Regular consumption of millet (proso millet) Use of medications affecting carbohydrate metabolism Insulin therapy History of alcohol or substance dependence Major surgery within the previous 6 months Thyroid disease, including hypothyroidism or hyperthyroidism Engagement in high-intensity physical activity (e.g., professional athletes) Habitual consumption of a high-fiber diet Sleep disorder or night-shift work Antibiotic treatment Blood transfusion within the previous 3 months Presence of other endocrine disorders that may affect glucose metabolism Inability or unwillingness to comply with the study protocol Fasting capillary blood glucose at 0 minutes <70 mg/dL or >150 mg/dL, or HbA1c >7.5% Heavy exercise within the previous 48 hours Current infection Smoking or alcohol consumption before the test session Caffeine consumption within the previous 24 hours Acute stress Use of medications that may affect blood glucose, such as corticosteroids or beta-blockers