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Last updated July 6, 2020. 5 minute read

Vitamin D and depression: how are they connected?

Several studies have found that low levels of vitamin D are associated with depression. But it’s unclear whether supplementing with additional vitamin D can help.

Self Written by Michael Martin
Reviewed by Dr. Mike Bohl, MD, MPH

Depression is a widespread and increasingly common condition. But 70 years after the release of the first antidepressant drugs, science still hasn’t gotten closer to a magic bullet—or even to fully understanding what causes depression. Research has recently turned to whether certain vitamins and supplements can have an effect on depressive symptoms and mood disorders. One of them is vitamin D.


  • Vitamin D is a prohormone that supports several body systems, including the heart and bones.
  • Several studies have found that low levels of vitamin D are associated with depression.
  • But it’s unclear whether supplementing with additional vitamin D can help.
  • If you’re concerned about your vitamin D level, see a healthcare provider.

What is vitamin D?

Potential trivia answer first: Vitamin D isn’t actually a vitamin. Technically, it’s a prohormone—something the body makes and converts to a hormone—that has a role in several important bodily processes. Known as the “sunshine vitamin,” vitamin D is made by the body as a response to sun exposure. When sunlight hits the skin, the body produces a substance that the liver and kidneys convert to forms usable by various organs and systems.


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Vitamin D seems to have several benefits, including helping bones stay strong and preventing osteoporosis (Bischof-Ferrari, 2005), boosting the immune system (Aranow, 2011), providing protection from several cancers (including breast and colon) (Meeker, 2016), helping the body regulate insulin and reducing the risk of diabetes (Schwalfenberg, 2008), and reducing the risk of cardiovascular disease, including heart disease and stroke (Vacek, 2012).

Vitamin D is found in a variety of foods, including eggs and milk. But much of the world’s population is deficient in vitamin D—up to 1 billion people worldwide, and 40% of Americans (Parva, 2018).

Vitamin D and depression

Can low levels of vitamin D in your body impact your mental health? The science is kind of up in the air. There is a slight link between a low bodily level of vitamin D and depression, but it’s not clear whether a low level of vitamin D causes depression, depression depletes vitamin D, or some other factor impacts both (Geng, 2019). It’s also unclear whether supplementation can help relieve depressive symptoms.

Many studies have found lower-than-optimal levels of vitamin D to be associated with depression (von Känel, 2015). A meta-analysis of studies involving more than 31,000 people found that low vitamin D levels were found in depressed people, as compared to a control group (Anglin, 2013).

But is the solution just taking more vitamin D? A 2020 review published in the journal Depression & Anxiety analyzed 25 studies involving more than 7,500 people and found that vitamin D supplementation had a positive effect on patients with major depressive disorder (Cheng, 2020).

However, if you’re experiencing only mild symptoms of depression, just adding a vitamin D supplement to your daily routine might not perk you up.

A 2015 meta-analysis of studies published in the journal Nutrition looked at randomized controlled trials involving 5,000 people and found that vitamin D supplementation had “no significant reduction in depression.” But, the researchers noted, the studies they examined “focused on individuals with low levels of depression” who had adequate vitamin D levels to begin with (Gowda, 2015).

Researchers aren’t sure why vitamin D might have an effect on depression, but they have some theories. Three areas in the brain that help regulate emotions—the prefrontal cortex, hypothalamus, and substantia nigra—have vitamin D receptors. Vitamin D also helps regulate levels of serotonin, and lower levels of vitamin D might lead to lower concentrations of serotonin in the brain (several antidepressant medications aim to alleviate depression by boosting serotonin levels). Vitamin D also helps the brain dispense the natural chemicals dopamine and norepinephrine; low levels of both have been observed in people with depression (Pittampalli, 2018).

How to get more/enough vitamin D

Good sources of vitamin D in food include fatty fish (such as salmon and tuna), fish oil, fortified milk, eggs, and fortified breakfast cereals.

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You could also take a vitamin D supplement. The Office of Dietary Supplements recommends a daily intake of vitamin D of 600 IU for adults up to age 69 and 800 IU for adults 70 and older. The tolerable upper daily limit is 4,000 IU (100 mcg). Be careful when taking vitamin D supplements—vitamin D toxicity is possible (NIH, n.d.).

If you’re concerned that you might have a low level of vitamin D, talk with your healthcare provider, who can check your vitamin D status with a simple blood test.