Skip to main content
OpenTrials
Active, Not Recruiting

NCT Number: NCT05980884

Using Gut Microbial Gbu Gene Testing to Estimate Host TMAO Production Capacity

The risk of cardiovascular diseases from red meat consumption varies among individuals due to variations in gut microbiota. L-carnitine in red meat can be converted to TMAO in the body by certain bacteria. Not everyone experiences a significant increase in TMAO levels after consuming carnitine. Gut microbiota differences are observed between high and low TMAO producers. The presence of the gbu gene in gut microbiota is linked to TMAO production. This clinical research aims to determine if the gbu gene can predict TMAO levels after dietary carnitine intake.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Notify Me

Key information

Age range

18 year–70 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

National Taiwan University Hospital

Taipei, Taiwan

About this study

The risk of developing cardiovascular diseases due to the consumption of red meat varies among individuals, and this may be attributed to differences in the composition and function of gut microbiota. Studies have found that red meat, rich in L-carnitine, may be metabolized by certain anaerobic bacteria in the intestines to produce trimethylamine N-oxide (TMAO) in the human body. Previous research utilizing the oral carnitine challenge test (OCCT) revealed that not everyone experiences a significant increase in blood TMAO levels after consuming carnitine. Moreover, individuals with high TMAO production and low TMAO production showed distinct differences in their gut microbiota.

Furthermore, we have discovered a significant correlation between the abundance of the gbu gene in gut microbiota and the production of TMAO in response to dietary carnitine intake. Therefore, through the design of clinical research, we aim to investigate and assess whether the abundance of the gbu gene in gut microbiota can predict the levels of TMAO produced in the human body under dietary carnitine intake.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Adult with age between 18 to 70
  • Must be able to swallow tablets

Exclusion criteria

  • Antibiotics use within one month
  • L-carnitine supplement use within one month
  • Chronic diarrhea
  • Myasthenia gravis
  • Diabetes mellitus
  • Parathyroid disorders
  • Chronic kidney disease
  • Epilepsy
  • Severe anemia
  • Cardiovascular diseases.

Treatment and study plan

L-carnitine

Dietary Supplement

Participants are required to take a capsule containing 500mg L-carnitine/day continuous for 7-10 days.

Primary outcomes

  1. Blood TMAO level measured by LC-MS/MS

    Time frame: up to 7-10 days

  2. Urine TMAO level measured by LC-MS/MS

    Time frame: up to 7-10 days

  3. Fecal gbuB gene abundance measured by qPCR

    Time frame: up to 7-10 days

Secondary outcomes

  1. Carnitine intake measured by 24hr dietary record

    Time frame: up to 7-10 days

  2. Gut microbiome profiles measured by shotgun metagenome sequencing

    Time frame: up to 7-10 days

Sponsors and collaborators

Lead sponsor

National Taiwan University Hospital

Other

Registry information

Official study title

Evaluation of Microbial-derived TMAO Production From Carnitine Intake by Testing Fecal Gbu Gene

Important dates

Study start
2023
Primary completion
2026
Study completion
2026
First posted
Aug 8, 2023
Registry last updated
Jan 12, 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.

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