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.

(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. - Pregnancy. - 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