Myths vs facts: Cortisol and Darmgesundheit

Cortisol and gut health are linked, but many claims overstate the evidence. Fact: Chronic stress elevates cortisol, which can impair gut barrier function („leaky gut“) and alter microbiome composition. Studies show higher cortisol correlates with lower bacterial diversity and increased inflammation. Myth: A single DNA test (e.g., NR3C1 variants) reliably predicts your cortisol sensitivity or dictates a specific diet. Common variants have negligible effects. Also, no specific supplement or diet is proven to directly lower cortisol in a clinically meaningful way. Evidence is observational and mechanistic, not from large RCTs. Be skeptical of marketing that sells DNA-based cortisol diets. Bottom line: Focus on stress management, sleep, fiber-rich foods, and overall lifestyle. The science is real but the effect sizes are small and individual responses vary.