Vitamin D is an essential nutrient that plays a role in bone health, immune function, and cell growth. Although some research has shown a link between low vitamin D and depression, there is no evidence that low levels cause depression.

People often associate vitamin D with sunshine, but it is available through food sources, too. Some people who find it difficult to consume enough of the vitamin choose to take supplements.

There is no proof that low levels cause depression or other mental health conditions, but experts do know that many people with depression have low vitamin D. This may be due to lifestyle factors such as inadequate nutrition and a lack of time outdoors.

Certain factors can increase the risk of having low vitamin D. These include having dark skin, being pregnant, having obesity, and living with a health condition such as gout or multiple sclerosis (MS).

This article looks at the link between vitamin D and depression. It also discusses the symptoms and treatment of vitamin D deficiency and depression.

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A 2020 systematic review of 61 studies found that there was a link between vitamin D and depression. However, it neither determined why this link existed nor showed a causal relationship.

Other researchers have investigated the link with the aim of identifying causation. For a 2020 randomized clinical trial, researchers recruited 18,353 adults aged 50 years or older without depression or depression symptoms. They gave some participants vitamin D supplements and others a placebo over the space of 5 years.

At the end of the study, they found no conclusive link between vitamin D and depression symptoms. They concluded that vitamin D3 supplementation did not play a role in preventing depression.

Despite being unable to prove causation, experts agree that vitamin D and depression are connected. This likely comes down to a complex combination of lifestyle factors and co-occurring conditions.

For example, people with depression may have difficulty eating a nutritious, well-balanced diet, so they may not be consuming enough dietary vitamin D. They may also be more likely to stay indoors, so their body is able to synthesize less vitamin D from sunlight.

Vitamin D is an essential fat-soluble vitamin. This means that the body absorbs it with fats and oils, storing it in fatty tissue.

One of its key roles in the body is aiding calcium absorption. It promotes healthy bone growth and remodeling, and without it, a person’s bones can become weak and brittle.

Additionally, it helps prevent hypocalcemic tetany. This involuntary contraction of the muscles can cause muscle cramps and spasms.

Other roles of vitamin D in the body include:

  • reducing inflammation in the body
  • promoting proper immune function
  • aiding in cell growth
  • regulating glucose metabolism, which is the process of the body breaking down carbohydrates for energy

The amount of vitamin D that a person needs varies depending on their life stage. People who have an increased risk of brittle bones, including older adults, need more vitamin D.

According to the National Institutes of Health (NIH), these are the recommended daily allowances (RDA) of vitamin D in micrograms (mcg):

Age/life stageRDA
0–12 months10 mcg
1–13 years15 mcg
14–18 years15 mcg
19-50 years15 mcg
51-70 years15 mcg
over 70 years20 mcg
pregnant or lactating15 mcg

Certain factors can increase a person’s risk of having low vitamin D levels.

Diet

Having a limited diet and not eating a variety of foods can increase a person’s risk of low vitamin D. As many animal products contain or are fortified with vitamin D, following a plant-based diet may also raise a person’s risk.

Limited sun exposure

People who do not get adequate unprotected sun exposure may not synthesize enough vitamin D. Those who live in regions with limited sunlight, such as in areas very far from the equator, are at particularly high risk.

Skin tone

Melanin inhibits vitamin D absorption, so people with dark skin will absorb less vitamin D than those with light skin.

A 2019 study used UV radiation to investigate vitamin D synthesis in people with different skin tones. It found that although melanin only inhibited a small amount of vitamin D3 production, this inhibition was enough to explain the differences across skin tones. The study authors advise people with dark skin to increase their UV exposure.

Obesity

A 2021 study found that low vitamin D was associated with depression in adults with obesity. However, the study merely showed a link and did not prove causation.

Some health conditions

Research has found a connection between vitamin D and depression in pregnant people and those with certain health conditions.

  • Pregnancy: A 2020 review of 14 studies found that some research suggested a link between vitamin D deficiency and postpartum depression (PPD). However, other research has not confirmed this. The authors note that poor sleep quality played a significant role.
  • Gout: A small 2019 study showed that low vitamin D was independently associated with depression in adults with gout.
  • Stroke: According to a 2015 study involving people who had had a stroke, those who developed depression afterward had significantly lower vitamin D levels than those who did not.
  • MS: A 2021 study found a correlation between low vitamin D and depression in people with MS. The authors note that this association was more prevalent in males.

Both vitamin D deficiency and depression can produce various symptoms.

Vitamin D deficiency symptoms

The possible symptoms of vitamin D deficiency include:

  • bone pain
  • muscle twitches
  • weakness
  • joint stiffness
  • muscle aches and pain
  • bone fractures

Learn more about vitamin D deficiency.

Depression symptoms

Some symptoms of depression include:

  • changes in sleep
  • appetite changes
  • changes in energy levels
  • lower pleasure in activities
  • feelings of worthlessness
  • poor concentration
  • low mood
  • suicidal thoughts

Learn more about the symptoms of depression.

Suicide prevention

If you know someone at immediate risk of self-harm, suicide, or hurting another person:

  • Ask the tough question: “Are you considering suicide?”
  • Listen to the person without judgment.
  • Call 911 or the local emergency number, or text TALK to 741741 to communicate with a trained crisis counselor.
  • Stay with the person until professional help arrives.
  • Try to remove any weapons, medications, or other potentially harmful objects.

If you or someone you know is having thoughts of suicide, a prevention hotline can help. The 988 Suicide and Crisis Lifeline is available 24 hours a day at 988. During a crisis, people who are hard of hearing can use their preferred relay service or dial 711 then 988.

Click here for more links and local resources.

Treatment options are available to address a vitamin D deficiency and lessen depressive symptoms.

Vitamin D deficiency

People with a vitamin D deficiency can increase their levels with nutritional changes, supplements, and increased sun exposure.

  • Dietary supplements: People can take supplements containing vitamin D2, vitamin D3, or both.
  • Nutrition: Foods containing vitamin D include fatty fish, egg yolks, and some cheeses. Other foods, such as milk and cereal, are frequently fortified with vitamin D.
  • Sun exposure: Experts suggest that people get 5–30 minutes of unprotected sun exposure, ideally between the hours of 10 a.m. and 4 p.m.
  • Vitamin D lamps: Special UV lamps can recreate the effects of sunlight, and people often use them to treat seasonal affective disorder.

Depression

The treatment for depression usually involves a combination of therapy and medication.

Depression is a complicated condition, and people react differently to treatment methods. Most doctors will recommend an antidepressant, such as a selective serotonin reuptake inhibitor (SSRI), alongside talk therapy.

Learn more about the treatment options for depression.

Studies have shown a connection between low vitamin D levels and depression, but experts do not fully understand why this link exists. Some theories suggest that people with depression have lifestyle practices that make them more likely to have low levels of vitamin D.

People can treat low vitamin D levels with supplements, dietary changes, and increased sun exposure.