Nutrients and Functional Components of Medicine and Food Homology Substances on Antidepressant Effects: A Mechanism-Oriented Review

Depression is one of the most common mental disorders in modern society, and it has become a serious threat to human health. The limitations of existing antidepressant drugs have prompted people to turn to the multi-target, low-toxic side effects of natural products. This article reviews the conventional nutrients (omega-3 fatty acids, folic acid, and mineral elements) and functional active ingredients (flavonoids, polysaccharides, saponins, and terpenoids) in medicinal and food homologous substances (MFHs). They show antidepressant potential by regulating neurotransmitters, improving hypothalamic–pituitary–adrenal (HPA) axis function, promoting neuroplasticity, inhibiting neuroinflammation, regulating ferroptosis, and interfering with the gut–brain axis. In addition, this paper discusses the application prospects of modern technologies such as microbial fermentation and nano-delivery in improving the bioavailability of MFHs and product development. In summary, MFHs have potential application value in dietary intervention and adjuvant therapies for depression; in the future, randomized controlled clinical trials should be strengthened, and multi-omics technology should be combined to promote the development of precision products so as to provide a new perspective for the development of new antidepressant drugs.