wie oft sollte man kefir trinken — when to see a doctor?

The optimal amount of kefir depends on individual tolerance. Generally, 1–2 servings (150–250 ml) per day are considered safe and may support gut health. However, evidence for specific health claims is limited – many studies are small or observational. You should see a doctor if you experience new gastrointestinal symptoms (bloating, diarrhea, cramps), have a weakened immune system (e.g., after chemotherapy), known lactose or milk protein allergy, or if you intend to replace prescribed medications (e.g., blood pressure drugs) with kefir. Caution is also advised if you take blood thinners (vitamin K content) or have histamine intolerance. Genetic tests for individual tolerance have low predictive value. Kefir is a food, not a medicine.