The first seven years of life constitute a critical period where the brain develops at a near-fetal rate, and the experiences lived during this phase set the definitive limits of our neuroplasticity and the health of our microbiota for the rest of our existence.

noli's read

Neurodevelopmental research confirms that early childhood is characterized by phenomenal synaptic growth, with the brain reaching approximately 90% of its adult size by age 5 (scientific consensus from the Harvard Center on the Developing Child). Similarly, observational cohorts (such as the CHILD study) validate the existence of a critical window during the first years of life where the intestinal ecosystem stabilizes and durably influences our immunity. However, the claim that our adult brain plasticity or the flexibility of our microbiota is definitively constrained by these first seven years is exaggerated. Neuroscience research (functional imaging studies) shows that the brain retains a remarkable capacity for adaptation and learning at any age. Finally, clinical trials (RCT) on dietary transitions and lifestyle habits prove that an adult can profoundly enrich their bacterial diversity, demonstrating that there is no absolute biological determinism.

the sources

No named source held this one up — that absence is part of the verdict.