Theobromine From Cocoa and Cardiovascular Risk Factors

March 16, 2026 updated by: Siraphat Taesuwan, Chiang Mai University

Theobromine Consumption From Cocoa and Cardiovascular Risk Factors in Humans: Evidence for Health Claims

The goal of this clinical trial is to examine whether consumption of dark chocolate affects blood pressure and a cardiovascular risk factor called trimethylamine N-oxide in Thai male participants with hypertension. The main questions it aims to answer are:

Can consumption of dark chocolate lower blood pressure? Can consumption of dark chocolate lower blood trimethylamine N-oxide?

Researchers will compare dark chocolate to white chocolate to see if the effects are due to theobromine (a key bioactive compound in dark chocolate).

Participants will consume either 100 g 72% dark chocolate bar or 80 g white chocolate bar daily for 14 days, rest for 7 days, and then switch to the other type of chocolate.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

This is a randomized cross-over trial conducted in Chiang Mai, Thailand. The goal of this clinical trial is to examine whether consumption of dark chocolate affects cardiovascular risk factors, with the primary outcomes being blood pressure and a cardiovascular risk factor called trimethylamine N-oxide. Participants are Thai males aged 35-70 years with hypertension who live in the Chiang Mai area.

42 Participants will consume either 100 g 72% dark chocolate bar (~2.5 servings, providing ~900 mg theobromine) or 80 g white chocolate bar (~2 servings, providing 0 mg theobromine) daily for 14 days. After a 7-day wash-out period, the participant will repeat the protocol with the other intervention.

Study Type

Interventional

Enrollment (Actual)

53

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Thailand
    • Chiang Mai
      • Mueang, Chiang Mai, Thailand, 50200
        • Research Institute for Health Sciences, Chiang Mai University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion criteria

  • Male
  • Age between 35 to 70 years
  • BMI less than 30 kg/m^2
  • Systolic blood pressure between 130 to 159 mmHg or Diastolic blood pressure between 85 to 99 mmHg.
  • Do not smoke.

Exclusion criteria

  • Cannot drink beverages and consume foods that have caffeine.
  • Take medicine to lower cholesterol and triglyceride levels, treat high blood pressure, or diabetes.
  • Have liver and kidney inflammation.
  • Use antibiotics within 1 month of study.
  • Use choline or probiotic supplements regularly within 1 month of study.
  • Consume more than 30 alcoholic drinks per week.
  • Have chronic diseases.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Dark chocolate
100 g/day of dark chocolate
Other: dark chocolate
Consumption of 100 g/day of 72% dark chocolate bar for 14 days consecutively
Placebo Comparator: White chocolate
80 g/day of white chocolate
Other: white chocolate
Consumption of 80 g/day of white chocolate bar for 14 days consecutively

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Blood pressure
Time Frame: Measured at the beginning and the end of each intervention period (14 days)
Office blood pressure measured in the morning after fasting
Measured at the beginning and the end of each intervention period (14 days)
Fasting blood trimethylamine-N-oxide
Time Frame: Measured at the beginning and the end of each intervention period (14 days)
Fasting blood trimethylamine-n-oxide concentrations
Measured at the beginning and the end of each intervention period (14 days)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Postprandial trimethylamine-N-oxide
Time Frame: Measured at the beginning and the end of the dark chocolate intervention (14 days)
Urinary trimethylamine-N-oxide concentrations at 24 and 48 hours after consumption of a test meal (3 boiled eggs)
Measured at the beginning and the end of the dark chocolate intervention (14 days)
Ankle-brachial index
Time Frame: From the beginning and end of each intervention period of 14 days
Ankle-brachial index is a noninvasive test that measures the ratio of blood pressure in the ankle to the blood pressure in the arm.
From the beginning and end of each intervention period of 14 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Chiang Mai University

Investigators

  • Principal Investigator: Kongsak Boonyapranai, Doctoral degree, Research Institute for Health Science, Chiang Mai University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

February 15, 2025

Primary Completion (Actual)

April 30, 2025

Study Completion (Actual)

April 30, 2025

Study Registration Dates

First Submitted

February 6, 2025

First Submitted That Met QC Criteria

February 6, 2025

First Posted (Actual)

February 11, 2025

Study Record Updates

Last Update Posted (Actual)

March 18, 2026

Last Update Submitted That Met QC Criteria

March 16, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 21/67

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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