Plasma Trimethylamine N-oxide Elevation Induced by L-carnitine Supplementation and Insulin Resistance

NCT ID: NCT05251207

Last Updated: 2025-10-03

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

ACTIVE_NOT_RECRUITING

Clinical Phase

NA

Total Enrollment

40 participants

Study Classification

INTERVENTIONAL

Study Start Date

2022-02-07

Study Completion Date

2027-05-31

Brief Summary

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The primary aims of the current study:

* using L-carnitine supplementation modulate the level of plasma trimethylamine N-oxide to assess its effect on circulating cytokines related to diabetes and metabolic syndrome;
* using simulated night-shift work intervention as a stress factor, explore the effect of circulating metabolites on insulin sensitivity

The secondary aim is to evaluate the effect of carnitine supplementation on gut microbiome composition.

Detailed Description

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Subjects will be randomly divided in two groups: supplemented by L-carnitine 2g/day for 12 weeks, and placebo group receiving leucine in identical gelatine capsules.

Subjects who successfully complete the protocol will be divided into four subgroups - two with a changed circadian cycle and two controls (supplemented and placebo). Subgroups with a changed daily cycle will be able to sleep between 8:00 and 17:00 for four consecutive days, while during the night they will stay active in the laboratory. The oral glucose tolerance test (OGTT) will be performed before and after the circadian cycle modification. Glucose levels will be monitored by FreeStyle Libre Sensor. Moreover, the activity of the participants will be monitored by wearable activity trackers.

Before supplementation, as well as before circadian cycle modification and after finishing the whole experimental procedure, fasting blood samples will be collected for determination of plasma trimethylamine N-oxide (TMAO), trimethylamine (TMA), carnitine (free and acyl derivatives), protein markers of diabetes and inflammation.

Moreover, the stool samples will be collected before and after 12 weeks of supplementation, to determine the composition of the gut microbiome. In addition diet of participants will be monitored.

Conditions

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Insulin Resistance

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

PREVENTION

Blinding Strategy

DOUBLE

Participants Investigators

Study Groups

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carnitine

2 grams of L-carnitine per day for 12 weeks

Group Type EXPERIMENTAL

L-carnitine

Intervention Type DIETARY_SUPPLEMENT

L-carnitine-L-tartrate

Change of the circadian cycle

Intervention Type BEHAVIORAL

Reducing sleep at night for four consecutive days (enabling sleep between 8:00 and 17:00)

leucine

2 grams of L-leucine per day for 12 weeks

Group Type PLACEBO_COMPARATOR

L-leucine

Intervention Type DIETARY_SUPPLEMENT

L-leucine

Change of the circadian cycle

Intervention Type BEHAVIORAL

Reducing sleep at night for four consecutive days (enabling sleep between 8:00 and 17:00)

modified circadian cycle

no sleep at night for four consecutive days (enabling sleep between 8:00 and 17:00).

Group Type EXPERIMENTAL

L-carnitine

Intervention Type DIETARY_SUPPLEMENT

L-carnitine-L-tartrate

L-leucine

Intervention Type DIETARY_SUPPLEMENT

L-leucine

normal circadian cycle

sleep at night for four consecutive days

Group Type ACTIVE_COMPARATOR

L-carnitine

Intervention Type DIETARY_SUPPLEMENT

L-carnitine-L-tartrate

L-leucine

Intervention Type DIETARY_SUPPLEMENT

L-leucine

Interventions

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L-carnitine

L-carnitine-L-tartrate

Intervention Type DIETARY_SUPPLEMENT

L-leucine

L-leucine

Intervention Type DIETARY_SUPPLEMENT

Change of the circadian cycle

Reducing sleep at night for four consecutive days (enabling sleep between 8:00 and 17:00)

Intervention Type BEHAVIORAL

Eligibility Criteria

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Inclusion Criteria

* healthy volunteers,
* must be able to swallow tablets

Exclusion Criteria

* smokers,
* cardiovascular disease
* liver disease
* kidney disease
* gastrointestinal disorders (including stomach ulcers and erosions)
* diabetes
Minimum Eligible Age

20 Years

Maximum Eligible Age

30 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Poznan University of Physical Education

OTHER

Sponsor Role lead

Responsible Party

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Robert Olek

Principal Investigator

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Robert Olek, PhD

Role: PRINCIPAL_INVESTIGATOR

Poznan University of Physical Education

Locations

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Akademia Wychowania Fizycznego

Poznan, , Poland

Site Status

Countries

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Poland

References

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Samulak JJ, Sawicka AK, Hartmane D, Grinberga S, Pugovics O, Lysiak-Szydlowska W, Olek RA. L-Carnitine Supplementation Increases Trimethylamine-N-Oxide but not Markers of Atherosclerosis in Healthy Aged Women. Ann Nutr Metab. 2019;74(1):11-17. doi: 10.1159/000495037. Epub 2018 Nov 28.

Reference Type BACKGROUND
PMID: 30485835 (View on PubMed)

Bescos R, Boden MJ, Jackson ML, Trewin AJ, Marin EC, Levinger I, Garnham A, Hiam DS, Falcao-Tebas F, Conte F, Owens JA, Kennaway DJ, McConell GK. Four days of simulated shift work reduces insulin sensitivity in humans. Acta Physiol (Oxf). 2018 Jun;223(2):e13039. doi: 10.1111/apha.13039. Epub 2018 Feb 12.

Reference Type BACKGROUND
PMID: 29356345 (View on PubMed)

Other Identifiers

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2020/39/O/NZ7/01790

Identifier Type: -

Identifier Source: org_study_id

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