Vitamin D & Depression

By Charles Li, MD

TL;DR: Vitamin D vs. Depression

Vitamin D & Depression
Studies have found a link between Vitamin D Deficiency and depression. Individuals who are depressed tend to have lower Vitamin D levels.
Risk of Depression
Likewise, those with the lowest Vitamin D levels were around twice as likely to be depressed.
Inconclusive Trials
However, clinical trials have not been able to find conclusive evidence supporting Vitamin D supplements.


Unlike most vitamins, your body can actually make some of its own Vitamin D with the help of the sun. 

Your body needs the sun’s rays to catalyze an important step in producing Vitamin D.

key facts
  • Type
    Fat Soluble Vitamin
  • Source
    Diet, skin
  • Other Names
    calciferol, cholecalciferol
used for

Bone Growth



Vitamin D Key Facts: Vitamin D is a fat soluble vitamin that you obtain through your diet and through your own body's skin cells. Skin cells harness the sun to generate Vitamin D. It is also known as calciferol and cholecalciferol. Vitamin D is used for bone growth and immune system support.
How Vitamin D is made.
How Vitamin D is Made: Skin cells are believed to create 7-Dehydrocholesterol. UVB Rays from the sun convert this to Vitamin D3. Your liver and kidneys convert this to active Vitamin D. Vitamin D is then distributed throughout the body.

Not getting enough sun can lead to Vitamin D deficiency. Together with Vitamin D that you consume, your daily Vitamin D plays important role in absorbing nutrients, keeping your bones strong, and supporting your immune system. 

Vitamin D and Depression

Vitamin D has also been suspected to play a role in mental health.

Most studies that have looked at Vitamin D and depression have found a significant link.

A meta-analysis, which combined results from 10 studies, found that those with low Vitamin D are 31% more likely to be depressed.

However, as with all observational studies, this result only points to a correlation and doesn’t necessarily indicate that Vitamin D causes good mental health.

Low Vitamin D & Depression
Risk of Depression
High Vit D
Low Vit D
1.31x odds (1.0-1.7)
10 Cross-sectional Studies
A meta-analysis has found a link between low Vitamin D & depression. By combining data from 10 cross sectional studies, researchers found that those with low Vitamin D have a 31% higher chance of being depressed.
Study Source
From the abstract:

"Our analyses are consistent with the hypothesis that low vitamin D concentration is associated with depression"

Vitamin D deficiency and depression in adults: systematic review and meta-analysis

Clinical Trials: Vitamin D & Depression

Clinical trials of Vitamin D have so far been unable to confirm this link. One trial of nearly 20,000 volunteers gave Vitamin D to some and a placebo to others. Those that received Vitamin D were slightly less likely to get depression. However, the results were not significant.

Clinical Trial
Vitamin D & Depression
Risk of Depression
No Difference
Vit. D Supplements
0.97x (0.87-1.09)
Non-depressed, Older than 50
Duration: 5.3 years
Clinical trials of Vitamin D as a treatment for depression have not found significant benefit. Those given Vitamin D supplements in the trial above did not experience significantly less depression than those who were not given supplements.
Study Source
From the abstract:

Among adults aged 50 years or older without clinically relevant depressive symptoms at baseline, treatment with vitamin D3 compared with placebo did not result in a statistically significant difference in the incidence and recurrence of depression or clinically relevant depressive symptoms or for change in mood scores over a median follow-up of 5.3 years.

Effect of Long-term Vitamin D3 Supplementation vs Placebo on Risk of Depression or Clinically Relevant Depressive Symptoms and on Change in Mood Scores