Vitamin D and depression: what links currently exist?

Medically reviewed by Neka Miller, PhD on February 15, 2021. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

While the “sunshine vitamin,” or vitamin D, is a key nutrient when it comes to your physical well-being, could vitamin D also have an impact on mental health and play a role in depression? Keep reading for more on vitamin D and depression and find out if there’s a connection.

Wondering if your vitamin D levels might be too low? Easily check your vitamin D status with the Everlywell at-home vitamin D deficiency test.


What is vitamin D?

Vitamin D, also referred to as calciferol, is an essential fat-soluble vitamin that is naturally found in fatty fish, egg yolks, red meat, and various other foods. It’s also commonly added to foods like dairy products, breakfast cereals, and juice (foods with added vitamins are known as fortified foods).

Vitamin D is the only essential vitamin your body can make on its own, instead of having to get it from the food you eat. That’s because vitamin D production in the body is triggered when sunlight lands on your skin (which is why vitamin D is popularly known as the “sunshine vitamin”).

Vitamin D influences many different aspects of health. It is best known for its partnership with calcium. Vitamin D allows for proper metabolism and absorption of calcium in the gut to ensure bone mineralization and growth. Vitamin D also has effects on immune system function and may help reduce ongoing inflammation.

Check your vitamin D levels from the convenience of home with our easy-to-use Vitamin D Test.

Vitamin D and cognitive function

Along with its impact on bone health and the immune system, several lines of research hint at the possibility that vitamin D might play a role in cognitive function and brain health (though to be clear, this is still an area of ongoing research—and in many respects, definitive conclusions have yet to be reached).

In the first place, the hippocampus (an important part of the brain) and much of the central nervous system have vitamin D receptors (these are unique structures on the surface of some cells that vitamin D molecules are able to latch onto, thereby affecting the cell’s activity). This suggests that vitamin D may influence aspects of the brain’s function.

Other research shows that vitamin D might have a protective effect against neurodegeneration, and vitamin D deficiency may be connected with a greater risk of dementia and Alzheimer’s disease.

Additionally, some studies have found that vitamin D deficiency is associated with changes in mood and that low levels of the “sunshine vitamin” might correlate with depression.

With that in mind, below we’ll dig deeper into the connection between vitamin D and depression—but first, let’s take a step back to consider what depression is.

Understanding depression

Depression is often misunderstood as just a case of the blues. While most people get sad from time to time, depression is typically characterized by a persistent, intense type of sadness (that can’t be turned off or shed away), feelings of emptiness or irritability, and a loss of motivation and interest in things one used to enjoy. In its most severe cases, depression may result in suicidal ideation or actual attempts at suicide. (Note: If you or someone you know is thinking about suicide and/or would like emotional support, call the National Suicide Prevention Lifeline at 1-800-273-8255.)

In addition, concentration and basic cognition can feel foggy for people who are experiencing depression. Depression is often also accompanied by anxiety and restlessness, and it seriously affects one’s quality of life.

Depression can also present with some physical symptoms. Some of these symptoms may include:

  • Sleep problems, like insomnia or sleeping too much
  • A general lack of energy and feelings of tiredness
  • A lack of appetite leading to sudden weight loss
  • Sudden, increased food cravings, resulting in rapid weight gain
  • Unexplained aches and pains, like headaches, back pain, and joint aches

What causes depression?

As with most mental health conditions, the cause of depression can involve a combination of many different factors. The root cause of depression in one person may not coincide with the reason for depression in someone else. Biological, psychological, and environmental factors may all play a role to varying degrees. Included under the umbrella of biological factors are genetics, hormones, nutrition, and more.

Currently, multiple studies suggest some kind of link between vitamin D status and depression. According to some of this research, people with depression were observed to have lower levels of vitamin D when compared to control groups.

Interestingly, in one 2014 study, not only were low vitamin D levels associated with depression, but also people experiencing more severe depression were especially likely to have lower levels. And some studies that control for variables like age, body mass index, gender, and smoking have also found this connection between low vitamin D status and depression.

That being said, a significant link between vitamin D and depression hasn’t yet been established beyond doubt—so the jury is still out on this question. On top of that, it’s important to keep in mind that if there’s a link between vitamin D and depression, this doesn’t necessarily mean that inadequate vitamin D levels cause depression. More research would need to be carried out to determine if low vitamin D triggers depression in some way or if, instead, they are related in some other way.

Vitamin D deficiency may not directly cause depression (correlation does not mean causation), but it may be a potential marker for depression. The link between the two may be more nuanced and complex than we currently understand, but there may be a distinct link between depression and vitamin D.

For example, consider that low vitamin D can point to a lack of sun exposure in your life. A lack of sunlight is also known to contribute to a type of depression known as seasonal affective disorder (SAD), which occurs during seasonal changes, usually starting in the fall and winter. During these months, reduced amounts of sunlight can cause fluctuations in one’s natural circadian rhythms and affect the balance of brain chemicals, contributing to depressive feelings. In a case like this, a drop in vitamin D levels would be connected with the onset of depressive feelings, but the cause of the depression would involve other factors.

The important thing when it comes to vitamin D and depression is to make sure you’re getting enough vitamin D and that you’re not experiencing vitamin D insufficiency. Because regardless of the specific way vitamin D might be linked to depression, having the right vitamin D level is key for a well-functioning body—which, in turn, can help support your mental well-being.

Checking your vitamin D levels

Interesting in learning what your vitamin D levels are like? If so, you can take the Everlywell Vitamin D Test—an easy at-home option that lets you conveniently collect a sample at home, send it to a lab for accurate testing (a prepaid shipping label is included with the kit), and get digital results in days.


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