Effect of Lemon Juice and Apple Cider Vinegar on Postprandial Blood Glucose and Satiety in Healthy Individuals

NCT07563985 | Recruiting DMC

• 1 other identifier: 10354421-2025/09-10
• Study Type: interventional
• Target: 15
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Satiety; Postprandial Glycemia

Keywords

Lemon Juice; Apple Cider Vinegar; Glycemic Response; Starch Hydrolysis; Satiety; Postprandial Glucose

Outcome Measures

Primary Outcomes (4)

• 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.

  Baseline (0 min) to 180 minutes postprandial on each test day (with 1-week washout between interventions)

• 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.

  Baseline (0 min) to 180 minutes postprandial on each test day

• 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.

  Baseline (0 min) to 180 minutes postprandial on each test day

• Peak Blood Glucose Level (mg/dL)

  Peak postprandial blood glucose level will be determined from capillary glucose measurements over the 180-minute period.

  Baseline (0 min) to 180 minutes postprandial on each test day

Secondary Outcomes (3)

• Subjective Appetite Score (VAS, mm)

  Baseline (0 min) to 180 minutes postprandial on each test day

• Time to Peak Glucose (minutes)

  Baseline (0 min) to 180 minutes postprandial on each test day

• Rate of Glucose Increase (mg/dL/min)

  Baseline (0 min) to 180 minutes postprandial on each test day

Study Arms (5)

Control (Water + White Bread)

EXPERIMENTAL

Participants consume white bread together with plain water only. This arm serves as the control condition to evaluate postprandial blood glucose response without any acidic additive.

Dietary Supplement: Control (Water + White Bread)

Lemon Juice 50 g

EXPERIMENTAL

Participants consume white bread together with water containing 50 g lemon juice. This arm evaluates the effect of low-dose lemon juice on postprandial blood glucose response and satiety.

Dietary Supplement: Lemon Juice 50 g

Lemon Juice 100 g

EXPERIMENTAL

Participants consume white bread together with water containing 100 g lemon juice. This arm evaluates the dose-dependent effect of lemon juice on postprandial blood glucose response and satiety.

Dietary Supplement: Lemon Juice 100 g

Apple Cider Vinegar 10 g

EXPERIMENTAL

Participants consume white bread together with water containing 10 g apple cider vinegar. This arm evaluates the effect of low-dose apple cider vinegar on postprandial blood glucose response and satiety.

Dietary Supplement: Apple Cider Vinegar 10 g

Apple Cider Vinegar 20 g

EXPERIMENTAL

Participants consume white bread together with water containing 20 g apple cider vinegar. This arm evaluates the effect of higher-dose apple cider vinegar on postprandial blood glucose response and satiety.

Dietary Supplement: Apple Cider Vinegar 20 g

Interventions

Control (Water + White Bread) DIETARY_SUPPLEMENT

Participants 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).

Control (Water + White Bread)

Lemon Juice 50 g DIETARY_SUPPLEMENT

Participants 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 50 g

Lemon Juice 100 g DIETARY_SUPPLEMENT

Participants 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.

Lemon Juice 100 g

Apple Cider Vinegar 10 g DIETARY_SUPPLEMENT

Participants 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 10 g

Apple Cider Vinegar 20 g DIETARY_SUPPLEMENT

Participants 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.

Apple Cider Vinegar 20 g

Eligibility Criteria

• Age: 18 Years - 35 Years
• Gender Eligibility Details: All self-identified genders are eligible to participate.
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Alanya Alaaddin Keykubat University: lead

Study Sites (1)

Alanya Alaaddin Keykubat University

Alanya, Antalya, 07400, Turkey (Türkiye)

RECRUITING

Related Publications (4)

• Freitas D, Le Feunteun S. Inhibitory effect of black tea, lemon juice, and other beverages on salivary and pancreatic amylases: What impact on bread starch digestion? A dynamic in vitro study. Food Chem. 2019 Nov 1;297:124885. doi: 10.1016/j.foodchem.2019.05.159. Epub 2019 May 24.

  PMID: 31253299 RESULT

• Ostman E, Granfeldt Y, Persson L, Bjorck I. Vinegar supplementation lowers glucose and insulin responses and increases satiety after a bread meal in healthy subjects. Eur J Clin Nutr. 2005 Sep;59(9):983-8. doi: 10.1038/sj.ejcn.1602197.

  PMID: 16015276 RESULT

• Gheflati A, Bashiri R, Ghadiri-Anari A, Reza JZ, Kord MT, Nadjarzadeh A. The effect of apple vinegar consumption on glycemic indices, blood pressure, oxidative stress, and homocysteine in patients with type 2 diabetes and dyslipidemia: A randomized controlled clinical trial. Clin Nutr ESPEN. 2019 Oct;33:132-138. doi: 10.1016/j.clnesp.2019.06.006. Epub 2019 Jul 9.

  PMID: 31451249 RESULT

• Freitas D, Boue F, Benallaoua M, Airinei G, Benamouzig R, Le Feunteun S. Lemon juice, but not tea, reduces the glycemic response to bread in healthy volunteers: a randomized crossover trial. Eur J Nutr. 2021 Feb;60(1):113-122. doi: 10.1007/s00394-020-02228-x. Epub 2020 Mar 23.

  PMID: 32201919 RESULT

Related Links

• Related Info

MeSH Terms

Interventions

Water

Intervention Hierarchy (Ancestors)

Hydroxides; Alkalies; Inorganic Chemicals; Anions; Ions; Electrolytes; Oxides; Oxygen Compounds

Central Study Contacts

Ezgi Toptaş Bıyıklı, Assistant Professor

CONTACT

90 505 751 96 21; ezgi.biyikli@alanya.edu.tr

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: OTHER
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor Dr. Ezgi Toptaş Bıyıklı

Model Details: The study will be conducted on 15 healthy volunteers aged 18-35 years. On separate test days, participants will consume white bread together with water, lemon juice solution, or apple cider vinegar solution. Postprandial blood glucose levels will be measured using a glucometer at 0, 15, 30, 45, 60, 90, 120, 150, and 180 minutes. Satiety will be assessed using a visual analog scale (VAS). From the recorded glucose values, peak glucose levels, maximum glucose increase, percentage glucose increase, time to peak glucose, and glucose rise rate will be calculated. The study also evaluates the effects of different amounts of lemon juice and apple cider vinegar on glycemic response and satiety in a comparative manner. The findings may provide preliminary evidence for future research and contribute to the understanding of simple dietary strategies for improving postprandial glycemic control.

Study Record Dates

• First Submitted: April 21, 2026
• First Posted: May 4, 2026
• Study Start: May 1, 2026
• Primary Completion (Estimated): July 1, 2026
• Study Completion (Estimated): July 1, 2026
• Last Updated: May 4, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)