Across 5 studies, all reported beneficial effects of vitamin D on reducing inflammation, with a predominant small effect size. Four of five studies found statistically significant results, including a meta-analysis showing a moderate reduction in inflammation (SMD: -0.40, 95% CI: -0.48 to -0.32, p < 0.01). The most studied populations were older adults and individuals with inflammatory conditions such as rheumatoid arthritis.
Caveats: Available evidence is overwhelmingly positive — clinical literature in this area is subject to publication bias (null-result studies are less likely to be published or indexed). Doses and study durations were not consistently reported, limiting ability to define an effective dose range. Some studies (e.g., the 2025 systematic review) did not report statistical significance for the vitamin D-specific effect on inflammation, introducing some uncertainty.
The meta-analysis demonstrated that vitamin D supplementation led to a decrease in inflammation (SMD: -0.40, 95% CI: -0.48 to -0.32, p < 0.01)
Across conditions, nutritional supplements such as PUFAs, vitamin D, pomegranate extract, and ginger demonstrated anti-inflammatory and immunomodulatory effects.
decreases the ... inflammatory state
High-dose vitamin D₃ has demonstrated benefits in specific populations, including improved bone mineral density, immune homeostasis, glycemic control, and reduced inflammation.
Elevated irisin levels, such as those observed with vitamin D supplementation, could prevent muscle wasting and fat gain in SO by improving insulin sensitivity and reducing inflammation.