We’re used to popping a probiotic capsule after a course of antibiotics or when we’re feeling bloated, hoping for quick relief. But have you ever wondered what exactly happens when billions of live bacteria enter your digestive tract? It’s not just “magic” or blindly populating an empty space. There’s a complex, multi-level interaction going on inside us at the cellular and molecular levels.

When we feel fear or anxiety, we often get a “sucking feeling” or “butterflies in our stomach.” From an evolutionary perspective, our brains never existed without signals coming from the gut. However, in today’s world, chronic stress has become the main enemy of our digestive system. З еволюційної точки зору наш мозок ніколи не існував без сигналів, які надходять із кишківника. Проте в сучасному світі хронічний стрес став головним ворогом нашої травної системи.

Have you promised yourself to give up sweets on Monday, but by Wednesday your hand is reaching for a chocolate bar or a bun? We tend to blame it on weak willpower, fatigue, or “bad genes.” However, modern science proves that the real mastermind behind our food cravings lies deep within us.

If you consider yourself 100% human, science is ready to argue with you. The number of human cells in our body is about 30 trillion, while the number of bacterial cells is about 38 trillion. That is, the ratio is about 50:50. In our gastrointestinal tract alone, about 2 kilograms of bacteria, viruses, fungi and protozoa live.