Food-derived substances without side effects have been reported to alleviate depression by improving neurotransmitter synthesis, modulating the activation of the brain-derived neurotrophic factor tropomyosin receptor kinase B (BDNF-TrκB) pathway, inhibiting the expression of inflammatory genes, and reshaping the intestinal flora of depressed mice [7,8]. The gene discussed is BDNF; the disease is major depressive disorder.