Evidence check: Kefir Darm in the context of Schlaf

The combination of kefir (a fermented dairy product with probiotics) and sleep is not well studied scientifically. Plausible mechanisms exist: the gut microbiome influences the production of neurotransmitters like serotonin and GABA via the gut-brain axis, which regulate sleep. Kefir contains lactic acid bacteria and yeasts that may modulate gut flora and indirectly improve sleep quality. However, evidence comes mainly from animal studies or small human trials with other probiotics (e.g., Lactobacillus, Bifidobacterium). Specific studies on kefir and sleep are largely lacking. MyBody-X tests can analyze the microbiome but cannot derive direct sleep recommendations from kefir. The evidence is therefore mechanistic and preliminary. Beware of exaggerated marketing claims. A balanced diet and sleep hygiene are more important.