Can Kefir Darm help with Schlaf?

Whether kefir (gut health) can improve sleep is not yet conclusively supported by strong evidence. Mechanistic studies suggest that probiotics may influence sleep via the gut-brain axis, e.g., by modulating neurotransmitters like serotonin or GABA, or by reducing inflammation and cortisol. Kefir, a fermented milk product rich in diverse bacteria and yeasts, has shown some promise in small human trials for stress reduction, but direct evidence for sleep improvement is limited. The evidence grade is mechanistic/mixed. Individual factors such as genetics (e.g., MTNR1B variants affecting glucose tolerance after late meals), overall diet, and sleep hygiene are more impactful. Kefir is generally safe, but those with lactose intolerance (even with the lactase persistence rs4988235 A allele, symptoms may still occur) should choose lactose-free versions. For chronic sleep issues, medical evaluation is recommended.