While this is a better understanding than the parent comment, it's not quite right either. The microbiome acquired at birth and early childhood is EXTREMELY ro

While this is a better understanding than the parent comment, it's not quite right either. The microbiome acquired at birth and early childhood is EXTREMELY robust to change throughout the rest of a lifetime. As an adult, it's frustratingly difficult / next to impossible to meaningfully change your microbiome. Even if you completely change your diet and you move across the world, your microbiome will be closer to what it was when you were 5 than it will be to anyone in your vicinity. This is a simplification, but the effect is spectacular. What the authors here claim is not that the microbiome is very plastic throughout your life-- merely that it retains some plasticity in very early childhood.