Is CYP2C19 useful for gut health?

CYP2C19 is a drug-metabolizing enzyme primarily known for its role in processing medications such as proton pump inhibitors (PPIs) and clopidogrel. There is no direct evidence that CYP2C19 genotype is useful for assessing or improving gut health in terms of microbiome composition, intestinal barrier function, or inflammation. The main indirect link is through PPI metabolism: poor metabolizers have higher PPI exposure, which can alter the gut microbiome over time. However, this is a pharmacological side effect, not a gut health biomarker. Some nutrigenetic claims suggest CYP2C19 influences metabolism of dietary compounds, but the evidence is weak and largely mechanistic. Consumer DNA tests that list CYP2C19 as relevant for gut health overstate its utility. Current evidence does not support using CYP2C19 genotyping for personalized gut health advice. Caution is warranted against marketing that implies a direct benefit.