Skip to main content
OpenTrials
Completed

NCT Number: NCT06820944

Theobromine From Cocoa and Cardiovascular Risk Factors

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.

Completed

Looking for future studies?

Notify Me

Key information

Conditions

Hypertension Cardiovascular Diseases Vascular Diseases

Age range

35 year–70 year

Sex eligibility

Male

Study type

Interventional

Phase

Not applicable

Primary location

Research Institute for Health Sciences, Chiang Mai University

Mueang, Chiang Mai, 50200, Thailand

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Dark Chocolate

Other

Consumption of 100 g/day of 72% dark chocolate bar for 14 days consecutively

white chocolate

Other

Consumption of 80 g/day of white chocolate bar for 14 days consecutively

Primary outcomes

  1. 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

  2. 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

Secondary outcomes

  1. 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)

  2. 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.

Sponsors and collaborators

Lead sponsor

Chiang Mai University

Other

Registry information

Official study title

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

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
Feb 11, 2025
Registry last updated
Mar 18, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.