Evidence check: COMT in the context of blood sugar

COMT (catechol-O-methyltransferase) is an enzyme that degrades catecholamines such as dopamine, epinephrine, and norepinephrine. The common Val158Met polymorphism (rs4680) alters enzyme activity: the Met variant reduces activity, leading to higher catecholamine levels. This can amplify stress responses and indirectly affect blood sugar, as catecholamines stimulate glucose release from the liver. Some studies have linked COMT variants to fasting glucose, insulin resistance, or type 2 diabetes risk, but the effects are small and inconsistent. The evidence is mixed: mechanistic plausibility and some GWAS hits exist, but no robust clinical prediction. A consumer DNA test for COMT cannot reliably indicate your personal blood sugar risk. Lifestyle factors—diet, exercise, sleep, stress management—are far more impactful. No specific dietary or supplement changes are warranted based on COMT alone. If you have concerns about blood sugar, consult a healthcare professional for proper testing and advice.