What role does BDNF play in longevity?

BDNF (Brain-Derived Neurotrophic Factor) is a protein that supports neuronal survival, growth, and synaptic plasticity. In the context of longevity, BDNF is linked to cognitive health in aging, neuroprotection, and possibly extended healthspan. Low BDNF levels have been associated with neurodegenerative diseases like Alzheimer's. However, direct causal evidence for BDNF extending human lifespan is limited; most data come from animal models or observational studies. The provided context does not include any specific information on BDNF. Therefore, the evidence level is 'mechanistic'. Consumer DNA tests that report BDNF variants should be interpreted cautiously, as they do not provide clinically validated predictions of longevity.