NCT02016430 · The Cleveland Clinic
Gut Flora Metabolite Reduction After Dietary Intervention (GRADY)
(GRADY)
What this study is about
Our group has recently identified the association between gut-flora-mediated carnitine and phosphatidylcholine metabolism, specifically trimethylamine-N-oxide (TMAO), and cardiovascular risk. This study investigates the ability for dietary intervention to modulate TMAO levels.
View original scientific description
Our group has recently identified the association between gut-flora-mediated carnitine and phosphatidylcholine metabolism, specifically trimethylamine-N-oxide (TMAO), and cardiovascular risk. This study investigates the ability for dietary intervention to modulate TMAO levels.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Cohort 1 Inclusion criteria:
- Men and women age 18 years or above.
- Elevated TMAO metabolizers (\>5 µM) based on screening test and/or eGFR \< 60 at most recent measurement.
- Willing to remain on aspirin or able to be off aspirin or aspirin products for 1 week prior to starting the study and staying on the same aspirin regimen during the duration of the study.
- Willing to sign the consent form and follow the study protocol, which includes a 12-week dietary modification. Cohort 2 Inclusion criteria:
- Men and women age 18 years or above.
- Willing to remain on aspirin or able to be off aspirin or aspirin products for 1 week prior to starting the study and staying on the same aspirin regimen during the duration of the study.
- Willing to sign the consent form and follow the study protocol.
- eGFR values ranging from 16-59 Cohort 3 Inclusion criteria:
- Men and women age 18 years or above.
- Willing to remain on aspirin or able to be off aspirin or aspirin products for 1 week prior to starting the study and staying on the same aspirin regimen during the duration of the study.
- Willing to sign the consent form and follow the study protocol.
Exclusion criteria
- (all cohorts):
- Significant chronic illness or end-organ dysfunction, including known history of uncompensated heart failure, renal failure, pulmonary disease, hematologic diseases.
- Active infection or received antibiotics within 2 months of study enrollment
- Use of over-the-counter probiotic within past month, or ingestion of yogurt within past 7 days
- Having undergone bariatric procedures or surgeries such as gastric banding or bypass.
- Any condition which, in the judgment of the Investigator, would place a patient at undue risk by being enrolled in the trial, or cause inability to comply with the trial
Where
- Cleveland, Ohio
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jun 25, 2026 · Source of record for eligibility and locations