Vitamin D is commonly known as the “sunshine vitamin” because we are able to synthesize vitamin D when our skin is exposed to sunlight. Vitamin D is important for healthy bones and muscles, a good immune system, glucose metabolism, and cell growth. But there are more than just the physical benefits of vitamin D, as this important vitamin also plays a role in mental health and cognitive function (1).
This article focuses on the links between low vitamin D and depression. For more information about vitamin D, see our previous articles:
- Signs of vitamin D deficiency
- How can I boost my vitamin D levels?
- What can increase the risk of low vitamin D?
What is depression?
Depression is also known as major depressive disorder. It is a common medical illness that is estimated to affect 1 in 6 people at some point in their life (2). Symptoms can range from mild to severe and can include:
- Feelings of sadness
- Losing interest in activities that previously enjoyed
- Appetite changes along with weight changes
- Changes in sleeping patterns (increased sleep or difficulties sleeping)
- Lack of energy
- More purposeless activity (e.g., pacing, handwringing)
- Slowed movements or speech
- Feelings of guilt or worthlessness
- Difficulty concentrating and making decisions
- Contemplating suicide
What evidence is there linking low vitamin D to depression?
Evidence has been shown in many studies that there is an association between low vitamin D and an increased risk of depression.
These studies have included large meta-analyses, such as a 2013 study of 31,424 participants, which showed lower vitamin D levels were found in people with depression compared to controls and an increased odds ratio of depression for the lowest versus highest vitamin D categories (3).
Another study published in 2014, analyzed 1892 participants in the Netherlands Study of Depression and Anxiety showed that low vitamin D levels were associated with the presence and severity of depressive disorder suggesting that low vitamin D may represent an underlying biological vulnerability for depression (4).
A 2017 review article examined multiple different studies to also reach the conclusion that there is an association between low vitamin D and depression. This article also discusses a link between vitamin D and Seasonal Affective Disorder (SAD), which is a depressive subtype characterized by symptoms that occur in the darkest time of the year (5).
A recent review article (January 2020) again found an inverse correlation between vitamin D levels and clinical depression (6). There have been a number of other studies that have also been published in recent years, each finding an association to some degree between low vitamin D and the risk of depression. However, whether this relationship is causal (i.e. low vitamin D causes depression) remains to be confirmed.
Are vitamin D supplements effective for treating depression?
Despite the increasing evidence supporting an association between low vitamin D and depression, there are conflicting results about whether or not vitamin D supplements are beneficial for reducing the risk and treating depression. This is likely because the actual relationship between vitamin D and depression has yet to be confirmed. It is likely that low vitamin D doesn’t actually cause depression, but maybe low vitamin D could be considered as a marker of depression, and other factors are also involved.
A recent clinical trial (published August 2020) investigated whether long-term supplementation with vitamin D3 could prevent depression in the general adult population. The study followed 18,353 adults for five years to see if there was a difference in rates of depression in those receiving a vitamin D3 supplement compared to those receiving a placebo. The results from this trial do not support the use of vitamin D3 in adults to prevent depression (7).
Another study in 2013 showed that daily vitamin D3 supplementation for 6 months did not provide a reduction in symptoms of depression (8).
However, a small November 2020 study found that a single parenteral administration of high-dose vitamin D was associated with significant improvements in depression over 12 weeks in individuals that had both major depression and vitamin D deficiency (9). This small study does have some limitations (e.g., small sample size and a single-center design); however, it does illustrate the there may be a vitamin D supplementation approach that is beneficial to treat depression.
How can I measure my vitamin D levels?
Checking your vitamin D levels is quick and simple. It just requires a simple finger prick blood sample with our Vitamin D Test. This test measures your blood concentration of 25-OH vitamin D, which is the main indicator of vitamin D status. This test can tell you if your levels are in the healthy optimal range, or if you have mild to moderate deficiency, or if you have a severe deficiency. It can also detect vitamin D levels that are too high (vitamin D toxicity), which can occur in people who take an excessive amount of vitamin D supplements.
1. Jones G. (2014). Vitamin D. In A. C. Ross, et al., Modern Nutrition in Health and Disease (11th ed). Philadelphia: Lippincott Williams & Wilkins.
2. What is Depression? American Psychiatric Association.
3. Anglin RES, et al. (2013) Vitamin D deficiency and depression in adults: Systematic review and meta-analysis. British J Psychiatry, 202(2): 100-107.
4. Milaneschi Y, et al. (2014). The association between low vitamin D and depressive disorders. Mol Psychiatry 19: 444–451.
5. Parker GB, et al. (2017). Vitamin D and depression. J Affect Disord. 208: 56-61.
6. Menon V, et al. (2020). Vitamin D and depression: A critical appraisal of the evidence and future directions. Indian J Psychol Med. 42(1): 11-21.
7. Okereke OI, et al. (2020). Effect of long-term vitamin D3 supplementation vs placebo on risk of depression or clinically relevant depressive symptoms and on change in mood scores. A randomized clinical trial. JAMA. 324(5): 471-480.
8. Hansen JP, et al. (2019). Vitamin D3 supplementation and treatment outcomes in patients with depression (D3-vit-dep). BMC Res Notes12(203).
9. Vellekkatt F, et al. (2020). Effect of adjunctive single dose parenteral Vitamin D supplementation in major depressive disorder with concurrent vitamin D deficiency: A double-blind randomized placebo-controlled trial. J Psychiatr Res. 129: 250-256.