Abstract <p>Brain-derived neurotrophic factor (BDNF) is widely recognized as a critical molecule for the survival, growth, and maintenance of neurons in both the central and peripheral nervous systems, as well as for the development of cognitive abilities and emotions. However, recent studies have shown that, in addition to its role as a universal brain “fertilizer”, BDNF acts as a metabotrophin linking neuronal signaling with systemic metabolism. BDNF serves as a key factor that integrates the body’s response to stress, physical activity, and food intake with cellular mechanisms underlying neural plasticity and normal brain function. The review presents evidence supporting BDNF as a bidirectionally metabolic “bridge”: body metabolism controls BDNF production in the brain, while brain BDNF regulates body metabolism. Disruption of this regulatory axis is associated with a broad range of neurological and somatic disorders, as well as their comorbidities. Cellular mechanisms associated with disruptions in BDNF functions are explored in detail through the example of alcohol dependence, a condition characterized by both impaired brain signaling and somatic pathologies accompanied by metabolic changes.</p>