alt Hacker News> A 2014 systematic review concluded that vitamin D supplementation does not reduce depressive symptoms overall but may have a moderate benefit for patients with clinically significant depression, though more high-quality studies were determined to be needed.
The meta-analysis cited in the article is from 2024 and specifically mentions the Shaffer et al. 2014 review cited by Wikipedia as being low quality:
> Some of the available reviews, owing to the limited number of trials and methodological biases, were of low quality (Anglin et al., 2013; Cheng et al., 2020; Li et al., 2014; Shaffer et al., 2014).
https://pmc.ncbi.nlm.nih.gov/articles/PMC11650176/