Vitamin D and Depression

This chapter discusses the relationship between vitamin D and depression, shedding light on the physiological functions of the unique characteristics of vitamin D, its synthesis, and its role in extraskeletal activities apart from its established function in bone metabolism. It further delves into the global prevalence of vitamin D deficiency and the rising incidence of depression worldwide. The link between vitamin D and depression is presented emphasizing the potential roles of vitamin D in neuromuscular and immune function. The document also discusses the purported mechanisms underlying the relationship between vitamin D and depression, including neuroinflammation, imbalance in calcium homeostasis, and deficiency in neurotransmitters. Furthermore, the document presents a comprehensive review of the existing literature on the topic, citing multiple studies and reviews to support the discussed findings. It covers various aspects, including the molecular basis of vitamin D, its impact on neurobehavioral health, and its association with depressive symptoms across different age groups primarily fetal origins, children, adolescents, adults, and older adults. Many studies suggest a possible connection between depression and vitamin D insufficiency, but the exact nature of this relationship and whether the supplementation of vitamin D could effectively treat depression remains ambiguous. Given that the link between vitamin D and depression has attracted attention, further well-designed trials are needed to establish causality, elucidate the practical consequences, and address the existing discrepancies and limitations in the evidence.