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

Not Applicable

Recruiting

• Conditions: Gut Dysbiosis for TMAO Production From L-carnitine Consumption
• Interventions: Dietary Supplement: L-carnitine

• Registration Number: NCT05980884
• Lead Sponsor: National Taiwan University Hospital

Brief Summary

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.

Detailed Description

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.

Study Timeline

• Study First Submitted: 2023-07-20
• Study Start: 2023-07-24
• Study First Submitted QC: 2023-07-31
• Study First Posted: 2023-08-08
• Status Verified: 2025-05
• Last Update Submitted: 2025-05-06
• Last Update Posted: 2025-05-11
• Primary Completion: 2026-04-25
• Study Completion: 2026-07-30

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 230

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.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
L-Carnitine supplementation	L-carnitine	Participants are required to take a capsule containing 500mg L-carnitine/day continuous for 7-10 days. During the intervention, participants are asked to collect urine sample and dietary record each day. Blood and fecal samples will be collected before and after the intervention. Each participant needs to complete a food frequency questionnaire.

Primary Outcome Measures

Name	Time	Method
Blood TMAO level measured by LC-MS/MS	up to 7-10 days
Urine TMAO level measured by LC-MS/MS	up to 7-10 days
Fecal gbuB gene abundance measured by qPCR	up to 7-10 days

Secondary Outcome Measures

Name	Time	Method
Carnitine intake measured by 24hr dietary record	up to 7-10 days
Gut microbiome profiles measured by shotgun metagenome sequencing	up to 7-10 days

Trial Locations

Locations (1)

National Taiwan University Hospital; 🇨🇳 Taipei, Taiwan