Your microbiome builds in infancy, matures through childhood, stabilizes in adulthood, transforms during pregnancy and lactation, and declines with age — though far less inevitably than once thought — and this chapter gives the typical pattern and maintenance levers for each stage.
IV. Life stages
Your genes determine only about 10–20% of your microbiome — environment and diet account for the rest — so microbiome-based "personalized" nutrition isn't yet worth paying for.


