The new meta-analysis covered a total of 53,235 study participants from 41 studies, including those with and without depression, people taking vitamin D supplements and people taking placebos, and individuals with a variety of physical conditions.
While the doses used varied, the typical vitamin D supplement was 50-100 micrograms [2,000 - 4,000 units] a day. In the participants with depression, vitamin D supplements were shown to be more effective than placebos at alleviating depressive symptoms.
Vitamin D supplements seemed to be most effective in shorter bursts (under 12 weeks), the researchers report. However, in healthy individuals, it was placebos that had a slightly greater impact on depressive symptoms.
"Our results suggest that vitamin D supplementation has beneficial effects in both individuals with major depressive disorder as well as in those with milder, clinically significant depressive symptoms," write the researchers in their published paper.
However, before we get ahead of ourselves, the data we have so far isn't enough to prove that low vitamin D levels cause depression, or that supplements are an effective treatment. Even though this new meta-analysis shows a link, previous research hasn't been quite so conclusive.
Note: Vitamin D supplementation does so many OTHER good things for you that IMO it's worth looking into whether you suffer from depression or not.
Soon electric car batteries will be reprocessed into lithium supplements.