Association between Vitamin D Supplementation and Mental Health in Healthy Adults: A Systematic Review

Journal of Clinical Medicine

Nov 2021

DOI: 10.3390/jcm10215156

Citations:32

Influential Citations:0

Systematic Reviews / Meta-Analyses

Enhanced Details

Methods

Adults (healthy status) from diverse settings and ages studied; subgroups included older/postmenopausal women, pregnant women, and endurance athletes. Study designs encompassed randomized controlled trials (including double‑blind, placebo‑controlled), quasi‑experimental trials, cross-sectional analyses, nested case–control studies, and other observational interventional designs; 14 studies were included in the review.

Intervention

Vitamin D regimens varied across 14 studies. Forms used included cholecalciferol (Vitamin D) and calcifediol in one trial. Doses ranged from 15 µg/day to 1250 µg/month or higher; weekly regimens included 500 µg/week and 1500 µg/week; monthly regimens included 1250 µg/month and 300 µg/month (calcifediol); bolus dosing included 2500 µg/day following a 500 µg/week period; single large annual doses such as 12,500 µg/year; durations spanned roughly 2 weeks to 3–5 years (with many in the 2–24 month range). Some regimens were combined with calcium or physical activity; all administrations were oral.

Results

Overall, Vitamin D supplementation did not demonstrate a consistent positive effect on mental health in healthy adults. Most studies showed no beneficial impact on depressive symptoms, mood, well‑being, quality of life, anxiety, or related outcomes; high‑quality studies often found no positive effects or conflicting results for depression. Some findings suggested potential benefits only in specific contexts (e.g., when combined with physical activity) or when dietary Vitamin D intake was considered rather than supplementation alone. Vitamin D should not be used as the sole intervention for improving mental health in healthy adults; correcting deficiency and using a broader approach (including physical activity and dietary patterns) may be appropriate, but robust evidence is lacking. More high‑quality, standardized trials are needed.

Limitations

Heterogeneous regimens and populations across studies; varied mental-health outcomes and measures; many studies with small samples or risk of bias; English-language peer‑reviewed publications only; data available up to October 2019; no meta-analysis due to incomparable results.

Abstract

Vitamin D is considered to be a crucial factor that influences symptoms of depression, negative emotions, and quality of life, but to date, no systematic review has been conducted with regard to its effect on other domains of mental health. The aim of the study was to evaluate the influence of vitamin D supplementation on mental health in healthy adults. The systematic review was registered in the PROSPERO database (CRD42020155779) and performed according to the PRISMA guidelines. The literature search was conducted in PubMed and Web of Science databases and included intervention studies published until October 2019. The human studies were included if the supplementation regimen involved the administration of a specified dosage of vitamin D to an adult sample. A total of 7613 records were screened and assessed independently by two researchers, based on their title, abstract, and full text sequentially. Finally, 14 studies were included, and their risk of bias was assessed using the Newcastle–Ottawa Scale (NOS). The studies were included if they presented the results of various doses of vitamin D, compared the supplementation results with the placebo effect, compared the outcome with no supplementation, or observed effect of specific dose applied. The assessed mental health outcomes mainly included depressive symptoms, or depression, well-being, quality of life, mood, general mental component, and anxiety, but single studies also included other parameters such as distress, impression of improvement, and fear of falling and flourishing. The results of the majority of studies did not confirm a positive influence of vitamin D supplementation. None of the high-quality studies (assessed using NOS), which evaluated outcomes other than depression, supported the hypothesis that vitamin D supplementation effectively ameliorates mental health issues, while they present conflicting evidence for depression. Some studies indicated that supplementation should be combined with physical activity to provide effective results, and that supplementation is less effective than vitamin D supply from food sources. The included studies were conducted in diverse populations and followed various doses and intervals of administration, so the results may be incomparable, which should be considered as a limitation. The conducted systematic review did not provide strong evidence for a positive effect of vitamin D supplementation on mental health in healthy adults. show less