This clinical study aims to examine how acidic drinks (lemon juice and apple cider vinegar) affect blood sugar when consumed with a starchy food. The study focuses on healthy individuals and aims to understand whether these drinks can slow the rise in blood sugar after meals and affect feelings of fullness.
The main questions this study aims to answer are:
Do lemon juice or apple cider vinegar lower the rise in blood sugar after a meal? Do these drinks increase feelings of fullness? Do different amounts change their effects?
Researchers will compare lemon juice and apple cider vinegar to see which one is more effective.
Participants will:
Consume white bread in the morning on an empty stomach with one of the following drinks:
Water only Water with lemon juice (50 g or 100 g) Water with apple cider vinegar (10 g or 20 g) Have a one-week break between each test. Have their blood sugar measured at regular intervals for 3 hours after eating. Report their level of fullness using a simple scale.
This study explores whether simple and practical dietary choices can help manage blood sugar levels. The findings may support new, easy-to-apply nutrition strategies for managing diabetes and weight.
Healthy male and female volunteers aged 18-35 years
Body Mass Index (BMI) between 18.5 and 25.0 kg/m²
Willingness to provide written informed consent
Ability to comply with study procedures and fasting requirements
Presence of any chronic disease (e.g., diabetes mellitus, cardiovascular disease, gastrointestinal disorders)
Food allergies or intolerances to study foods (white bread, lemon juice, apple cider vinegar)
BMI <18.5 or >25.0 kg/m²
Regular participation in high-intensity physical activity (≥5 days/week)
Crossover
Control (Water + White Bread)
Dietary supplementParticipants will consume 100 g of white bread together with plain water (no acidic additive). This condition serves as the control arm for assessing baseline postprandial glycemic response and satiety. Capillary blood glucose will be measured at baseline and at multiple time points up to 180 minutes following consumption. Satiety and appetite sensations will be assessed using a 100-mm visual analog scale (VAS).
Lemon Juice 50 g
Dietary supplementParticipants will consume 100 g of white bread together with 50 g of lemon juice diluted in water. This intervention is designed to evaluate the effect of a low-dose acidic beverage (citric acid source) on postprandial blood glucose response and satiety. Capillary blood glucose levels will be measured at predefined time points up to 180 minutes, and subjective appetite sensations will be assessed using a 100-mm VAS.
Lemon Juice 100 g
Dietary supplementParticipants will consume 100 g of white bread together with 100 g of lemon juice diluted in water. This condition evaluates the dose-dependent effect of citric acid intake on postprandial glycemic response, glucose peak, and satiety. Serial capillary blood glucose measurements and VAS-based appetite assessments will be conducted over a 180-minute postprandial period.
Apple Cider Vinegar 10 g
Dietary supplementParticipants will consume 100 g of white bread together with 10 g of apple cider vinegar diluted in water. This intervention aims to assess the effect of a low-dose acetic acid source on postprandial glucose regulation and satiety. Capillary blood glucose will be measured at multiple time points for 180 minutes, and subjective appetite ratings will be recorded using a visual analog scale.
Apple Cider Vinegar 20 g
Dietary supplementParticipants will consume 100 g of white bread together with 20 g of apple cider vinegar diluted in water. This intervention evaluates the potential dose-response effect of acetic acid on postprandial glycemic control, including glucose peak, incremental glucose response, and satiety perception over a 180-minute period.
Postprandial Blood Glucose (mg/dL)
Capillary blood glucose levels will be measured at baseline (0 min) and at 15, 30, 45, 60, 90, 120, 150, and 180 minutes after consumption of test meals. Measurements will be performed in duplicate and mean values will be used.
Incremental Area Under the Curve (iAUC)
Incremental area under the curve (iAUC) for postprandial blood glucose will be calculated based on capillary glucose measurements over 180 minutes.
Total Area Under the Curve (AUC)
Total area under the curve (AUC) for postprandial blood glucose will be calculated using capillary glucose measurements over 180 minutes.
Peak Blood Glucose Level (mg/dL)
Peak postprandial blood glucose level will be determined from capillary glucose measurements over the 180-minute period.
Subjective Appetite Score (VAS, mm)
Subjective appetite sensations (hunger, satiety, fullness, prospective food consumption, and desire for sweet foods) will be assessed using a 100-mm Visual Analog Scale (VAS) at baseline and at 15, 30, 45, 60, 90, 120, 150, and 180 minutes postprandially.
Time to Peak Glucose (minutes)
Time to reach peak postprandial blood glucose will be calculated from capillary glucose measurements.
Rate of Glucose Increase (mg/dL/min)
Rate of increase in postprandial blood glucose will be calculated based on capillary glucose measurements.
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