Overview
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.
Description
Glycemic response plays an important role in the prevention and management of metabolic conditions such as diabetes and obesity. Different foods can cause rapid or slow increases in blood sugar levels. One factor that may influence this response is the acidity of foods. Acidic components may slow starch digestion and delay the rise in blood glucose by affecting digestive enzymes and gastric emptying. However, there are limited studies examining how the acidity of meals influences glycemic response in practical, real-life conditions.
This study is designed to investigate the effects of consuming acidic beverages, specifically lemon juice and apple cider vinegar, together with a starch-rich food. The study will compare their effects on post-meal blood glucose levels and feelings of fullness in healthy individuals. Different amounts of these acidic components will also be evaluated to understand dose-related effects.
Participants will consume standardized meals under controlled conditions, and their blood glucose response and satiety levels will be monitored over time. The study follows a comparative approach to assess the relative effectiveness of each intervention.
The findings of this study may help identify simple and practical dietary strategies to support better blood sugar control. As lemon juice and vinegar are widely available and easy to include in daily meals, the results may offer accessible approaches for improving dietary habits and supporting metabolic health.
Eligibility
Inclusion Criteria:
- 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
- No history of chronic metabolic, gastrointestinal, or endocrine diseases
Exclusion Criteria:
- 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)
- Current or recent (past 3 months) smoking or smoking cessation
- Use of any medication or supplements affecting glucose metabolism
- History of eating disorders
- Pregnancy, lactation, or menopause
- Female participants currently in menstruation period (testing will be postponed during menstruation days)
- Alcohol consumption within 24 hours prior to testing days
- Caffeine intake or major dietary changes on the day before testing


