Effect of Using Bitter Melon, Blueberries and Cranberries on HbA1c and Diabetes Symptom Levels

NCT07233460 | Completed

• 1 other identifier: RCS05022024
• Study Type: interventional
• Target: 120
• Locations: 1 country
• Sites: 1

Brief Summary

This double-blind, randomized controlled trial investigated the effect of bitter melon, blueberry, and cranberry powder extract use on glycemic control and diabetes symptom levels in individuals with T2DM.

Conditions

Type 2 Diabetes Mellitus; Symptoms and Signs; Patient

Keywords

Type 2 Diabetes Mellitus; Complementary and alternative medicine; Symptoms and Signs; Cranberry; Bitter melon; Blueberry.

Outcome Measures

Primary Outcomes (2)

• HbA1c

  Unlike instant blood glucose values, HbA1c reliably reflects an individual's average blood sugar level over the past two to three months by measuring the amount of glucose bound to hemoglobin during the average lifespan of erythrocytes (approximately 120 days). Before starting the study (pre-test/week 0) HbA1c venous blood values were measured. Patients who voluntarily used bitter melon, blueberry, or cranberry continued to consume 1 teaspoon (10 g total) of powdered extract mixed with yogurt or water twice a day (morning and evening) for 12 weeks. At the end of the study (post-test/12th week), the was administered again to individuals HbA1c venous blood values were measured.

  12 week

• Diabetes Symptom Checklist Scale

  The scale consists of a total of 34 items. These categories are: neurology (3, 11, 15, 21, 25, 34), psychology (1, 2, 4, 6, 17, 20), cardiology (5, 8, 9, 13, 24, 26, 29, 30), ophthalmology (10, 14, 22, 28), psychology/cognition (7, 19, 27, 31, 33), and hyperglycemia (12, 16, 23, 32) Subdimensionss. Responses on the scale are numbered from 0 to 5, with "0" meaning "none" and "5" meaning "extremely." Before starting the study (pre-test/week 0), all group participants first completed "Diabetes Symptom Checklist Scale" were measured. Patients who voluntarily used bitter melon, blueberry, or cranberry continued to consume 1 teaspoon (10 g total) of powdered extract mixed with yogurt or water twice a day (morning and evening) for 12 weeks. At the end of the study (post-test/12th week), the "Diabetes Symptom Checklist Scale" was administered again to individuals were measured.

  12 week

Study Arms (4)

Bitter melon Group

EXPERIMENTAL

Before starting the study (pre-test/week 0), all group participants first completed the "Patient Information Form" and the "Diabetes Symptom Checklist Scale," and their HbA1c venous blood values were measured. At the end of the study (post-test/12th week), the "Diabetes Symptom Checklist Scale" was administered again to individuals in the three groups, and their HbA1c venous blood values were measured. In addition, telephone follow-up was conducted to determine whether the individuals had used the powdered extracts completely for 12 weeks.

Other: Bitter Melon Group

Blueberry Group

EXPERIMENTAL

Before starting the study (pre-test/week 0), all group participants first completed the "Patient Information Form" and the "Diabetes Symptom Checklist Scale," and their HbA1c venous blood values were measured. At the end of the study (post-test/12th week), the "Diabetes Symptom Checklist Scale" was administered again to individuals in the three groups, and their HbA1c venous blood values were measured. In addition, telephone follow-up was conducted to determine whether the individuals had used the powdered extracts completely for 12 weeks.

Other: Blueberry Group

Cranberry Group

EXPERIMENTAL

Before starting the study (pre-test/week 0), all group participants first completed the "Patient Information Form" and the "Diabetes Symptom Checklist Scale," and their HbA1c venous blood values were measured. At the end of the study (post-test/12th week), the "Diabetes Symptom Checklist Scale" was administered again to individuals in the three groups, and their HbA1c venous blood values were measured. In addition, telephone follow-up was conducted to determine whether the individuals had used the powdered extracts completely for 12 weeks.

Other: Cranberry Group

Control Group

NO INTERVENTION

Before starting the study (pre-test/week 0), all group participants first completed the "Patient Information Form" and the "Diabetes Symptom Checklist Scale," and their HbA1c venous blood values were measured. At the end of the study (post-test/12th week), the "Diabetes Symptom Checklist Scale" was administered again to individuals in the three groups, and their HbA1c venous blood values were measured.

Interventions

Bitter Melon Group OTHER

Patients who voluntarily used bitter melon powder extract continued to consume 1 teaspoon (10 g total) of powdered extract mixed with yogurt or water twice a day (morning and evening) for 12 weeks.

Bitter melon Group

Blueberry Group OTHER

Patients who voluntarily used bitter blueberry powder extract continued to consume 1 teaspoon (10 g total) of powdered extract mixed with yogurt or water twice a day (morning and evening) for 12 weeks.

Blueberry Group

Cranberry Group OTHER

Patients who voluntarily used cranberry powder extract continued to consume 1 teaspoon (10 g total) of powdered extract mixed with yogurt or water twice a day (morning and evening) for 12 weeks.

Cranberry Group

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Being 18 years of age or older,
• Volunteering to participate in the study,
• Being conscious and able to communicate,
• Having been diagnosed with T2DM at least 3 months prior and currently using oral antidiabetic medication,
• Be using one of the following powder extracts-bitter melon, blueberry, or cranberry-for the first time as a complementary treatment upon a physician's recommendation and be on the first day of use,
• Not taking any other medications that affect blood sugar,
• No allergy to bitter melon, blueberry, or cranberry,
• Not engaging in exercise,
• Taking 10g of bitter melon, blueberry, or cranberry powder extract daily.

You may not qualify if:

• Having previously received complementary therapy for DM, or having hearing loss.

Sponsors & Collaborators

• Hatice Demirağ, Ph.D: lead
• Karadeniz Technical University: collaborator

Study Sites (1)

Gümüşhane University

Gümüşhane, 29600, Turkey (Türkiye)

Location

MeSH Terms

Conditions

Diabetes Mellitus, Type 2; Signs and Symptoms

Condition Hierarchy (Ancestors)

Diabetes Mellitus; Glucose Metabolism Disorders; Metabolic Diseases; Nutritional and Metabolic Diseases; Endocrine System Diseases; Pathological Conditions, Signs and Symptoms

Study Officials

• Hatice Demirağ

  Study Principal Investigator Gümüşhane Universıty

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: The researcher who collected the data and the person who performed the statistics were blinded.
• Purpose: SUPPORTIVE CARE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Assistant Professor

Model Details: As no reference could be made to any previous four-group study on the subject, and considering the small size of the city where the research would be conducted, it was decided to include a total of 120 individuals with T2DM in the study sample, with 30 individuals in each group (bitter melon group, blueberry group, cranberry group, and control group). However, considering reasons such as death, withdrawal from the study, or missing data, it was decided to increase the sample size by 10% to 132 individuals.

Study Record Dates

• First Submitted: November 14, 2025
• First Posted: November 18, 2025
• Study Start: February 6, 2024
• Primary Completion: February 15, 2024
• Study Completion: May 15, 2024
• Last Updated: November 21, 2025

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)