Legume Flour Particle Size and Metabolic Responses to Bread

The clinical trial will include two groups: (a) apparently healthy adults (up to 35 years old) and (b) individuals diagnosed with T2DM (aged 40-65 years). The study will investigate the effect of flour particle size on postprandial glycemic responses to bread and appetite sensations.

Within the framework of the clinical study, a total of three bread products will be prepared. Their final recipes will be determined after a series of tests to ensure the desired properties and organoleptic characteristics.

Intervention 1: White wheat bread with conventional fine wheat flour Intervention 2: White wheat bread with the addition of 30% finely milled chickpea flour Intervention 3: White wheat bread with the addition of 30% chickpea flour of larger particle size (>1.6 mm)

Inclusion and Exclusion Criteria

• Group 1

Participants in Group 1 will be men and women aged 40-65 years with BMI < 31 kg/m², fasting glucose > 125 mg/dL, and HbA1c < 8.5%, diagnosed with T2DM for at least one year before entering the study.

Patients must be on stable treatment (hypoglycemic, lipid-lowering, antihypertensive) for at least 3 months prior to enrolment. Most participants will be individuals monitored at the Diabetes Clinic of the 1st Propaedeutic Department of Internal Medicine at Laiko General Hospital.

Individuals with conditions that could affect study outcomes (e.g., endocrine, cardiovascular, pulmonary, renal, or gastrointestinal disorders), those with sensitivity, intolerance, or allergy to any bread ingredients used in the clinical trial, pregnant or breastfeeding women, individuals with eating disorders, and those taking medications or supplements considered incompatible with the study will be excluded.

• Group 2

Group 2 will consist of apparently healthy men and women aged 18-35 years with BMI 18-25 kg/m², who are not following a diet program or dietary counseling during the study period.

Individuals with fasting glucose > 110 mg/dL, blood pressure > 160/100 mmHg, metabolic or dietary disorders, conditions that could affect the study outcomes (e.g., endocrine, cardiovascular, pulmonary, renal, or gastrointestinal diseases), those with sensitivity, intolerance, or allergy to the bread ingredients used, pregnant or breastfeeding women, and those taking medications that could affect the study (e.g., hypoglycemic drugs, appetite-modifying medications, or any other relevant medications) will be excluded.

All volunteers, after providing informed written consent, will undergo a blood sample collection to confirm eligibility based on defined criteria, as well as for additional hematological and biochemical analyses. Subsequently, each participant will have a Continuous Glucose Monitoring (CGM) sensor placed by trained personnel according to the manufacturer's instructions, in order to monitor glucose values throughout the postprandial protocol. Measurements will include the period following consumption of the first meal (bread) and a second standardized meal, consumed 3 h later.

Cohort Healthy Participants

Inclusion criteria

• Age: Adults aged 18-35 years.
• Health Status: Healthy individuals with no diagnosed chronic diseases, including diabetes, cardiovascular disease, or gastrointestinal disorders.
• Body Mass Index (BMI): 18.5-27 kg/m² (normal to overweight range).
• Fasting Glucose: Normal fasting plasma glucose (<100 mg/dL or <5.6 mmol/L).
• No regular use of medications known to affect glucose metabolism (e.g., insulin, metformin, corticosteroids).
• Ability and willingness to comply with study procedures, including continuous glucose monitoring and standardized test meals.
• Informed Consent: Ability to understand and provide written informed consent.

Exclusion criteria

• Diagnosed chronic diseases: Diabetes (type 1 or type 2), cardiovascular disease, kidney or liver disease, gastrointestinal disorders (e.g., celiac disease, inflammatory bowel disease).
• Abnormal glucose metabolism: Fasting plasma glucose ≥100 mg/dL (≥5.6 mmol/L) or HbA1c ≥5.7%.
• Medication use: Regular use of medications that affect glucose metabolism, insulin sensitivity, or digestion (e.g., metformin, corticosteroids, GLP-1 analogs).
• Allergies or intolerances: Allergy or intolerance to wheat, chickpeas, gluten, or other ingredients used in the study foods.
• Pregnancy or lactation: Women who are pregnant, breastfeeding, or planning pregnancy during the study period.
• Recent major weight change: Significant weight loss or gain (>5% body weight) in the past 3 months.
• Extreme physical activity: Competitive athletes or individuals engaging in extreme exercise regimens that could influence glucose metabolism.
• Inability to comply: Individuals unable or unwilling to follow study procedures, including continuous glucose monitoring and standardized test meals.

Cohort 2: Participants with Type 2 Diabetes Mellitus

Men and women aged 40-75 years. Body mass index (BMI) < 31 kg/m². Fasting plasma glucose > 125 mg/dL. HbA1c < 8.5%. Diagnosis of type 2 diabetes mellitus (T2DM) for at least 1 year before enrolment.

Stable treatment with hypoglycaemic, lipid-lowering, and/or antihypertensive medications for at least 3 months prior to enrolment.

Most participants will be recruited from the Diabetes Clinic of the 1st Propaedeutic Department of Internal Medicine, Laiko General Hospital.

Exclusion criteria

Endocrine, cardiovascular, pulmonary, renal, or gastrointestinal disorders that could affect study outcomes.

Sensitivity, intolerance, or allergy to any ingredients of the study breads. Pregnancy or breastfeeding. Eating disorders. Use of medications or dietary supplements considered incompatible with the study protocol.