The role of vitamin D in depression and anxiety disorders: a review of the literature

ABSTRACT

Background

Prevalence of mental health disorders continue to increase worldwide. Over the past decades, suboptimal vitamin D (VD) levels and gut dysbiosis have been associated with neurological dysfunction and psychiatric disorders.

Methods

In this review, we examined the available literature on VD and mental health disorders, particularly depression and anxiety, in both clinical and pre-clinical studies.

Results

Our extensive review failed to find a link between VD deficiency, depression, and anxiety-related behavior in preclinical animal models. However, strong evidence suggests that VD supplementation may alleviate symptoms in chronically stressed rodents, with some promising evidence from clinical studies. Further, fecal microbiota transplantations suggest a potential role of gut microbiota in neuropsychiatric disorders, although the underlying mechanisms remain to be fully elucidated. It has been postulated that serotonin, primarily produced by gut bacteria, may be a crucial factor. Hence, whether VD has the ability to impact gut microbiota and modulate serotonin synthesis warrants further investigation.

Conclusions

Taken together, literature has suggested that VD may serve as a key regulator in the gut-brain axis to modulate gut microbiota and alleviate symptoms of depression and anxiety. The inconsistent results of VD supplementation in clinical studies, particularly among VD deficient participants, suggests that current intake recommendations may need to be re-evaluated for individuals at-risk (i.e. prior to diagnosis) of developing depression and/or anxiety.

KEYWORDS:

• Vitamin D
• depression
• anxiety
• mental health
• gut-brain axis
• serotonin
• gut dysbiosis

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Karisa Renteria

Karisa Renteria is a M.S. candidate of the Nutrition and Foods Program at Texas State University. Her thesis project focuses on the impact of gut microbiota on vitamin D status and its implication in behavioral changes. She earned her B.A. in Psychology from Texas State University and plans to continue focusing on this research topic at the Ph.D. level.

Hien Nguyen

Hien Nguyen is a graduate student with Texas State University. She holds a B.S. in Nutritional Sciences from Texas State University.

Gar Yee Koh

Gar Yee Koh is an Assistant Professor with the Nutrition and Foods Program at Texas State University with a Ph.D. in Nutritional Sciences. Her research focuses on promoting gut health to prevent complications resulting from obesity and other metabolic diseases. Currently, she has expanded her research to investigate the impact of vitamin D on behavioral changes.