BDNF (Brain-Derived Neurotrophic Factor)
The brain's 'Miracle-Gro' protein that maintains neuronal plasticity
Definition
BDNF (Brain-Derived Neurotrophic Factor) is a protein of the neurotrophin family that regulates the survival, growth, and plasticity of neurons. It is essential for adult hippocampal neurogenesis (formation of new neurons in the key memory region) and long-term potentiation (LTP), the molecular mechanism of learning. Chronically low levels are associated with depression, cognitive decline, Alzheimer's, and Parkinson's disease.
Detailed explanation
BDNF binds to its TrkB receptor, activating intracellular cascades that stimulate neuronal protein synthesis, dendritic spine formation, and myelination. It works as a molecular fertiliser for the brain — hence the 'Miracle-Gro' nickname popularised by psychiatrist John Ratey.
Documented interventions that increase BDNF:
Aerobic exercise: 30-45 min of running or cycling at moderate-to-high intensity acutely raises BDNF up to 3× and chronically with regular training. Intermittent fasting: 16-48 h of fasting activates ketone body production that directly stimulates BDNF expression. Caloric restriction: effect demonstrated in humans by the CALERIE study. Deep sleep (N3): overnight memory consolidation requires BDNF peaks. Novel learning: learning a language or musical instrument stimulates BDNF expression in the hippocampus.
Exposure to pollution, sedentary behaviour, chronic stress, and depression reduce circulating BDNF. The Val66Met polymorphism (affecting ~30% of Europeans) reduces activated BDNF secretion and is associated with poorer antidepressant response.
Scientific sources
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