Vitamin D is an essential nutrient that you get primarily from exposure to the sun. If you don’t get enough of it, some research suggests you could be at a higher risk of depression.
However, research on whether vitamin D supplementation can alleviate symptoms of depression is mixed. Some studies have shown improvement in symptoms when taking vitamin D, while others have found no link.
If you have depression and are considering vitamin D supplementation, it’s important to talk to your healthcare provider about your options.
Vitamin D supports several body functions and is essential for overall health. The vitamin helps your body absorb calcium and is an important component in developing strong bones and teeth.
Together, calcium and vitamin D help protect your body from developing osteoporosis. This condition causes your bones to weaken and become brittle, making them more likely to break. Low vitamin D also makes you more susceptible to osteomalacia, a condition that causes bones to soften, leading to bone pain, muscle weakness, and bone deformities like rickets.
However, the role of vitamin D is not limited to bone health. It also has anti-inflammatory, antioxidant and brain-protective properties and supports several other bodily functions.
For example, an adequate amount of vitamin D can increase your immune system’s ability to fight viruses and other microbes. Your muscles rely on vitamin D to move, and your nerves use vitamin D to send messages between your brain and your body.
Vitamin D deficiency is common—affecting about 35% of adults in the United States—and has been linked to several health problems.
For example, vitamin D deficiency is associated with cancer, cardiovascular disease, diabetes, multiple sclerosis and autoimmune diseases. More recently, vitamin D has emerged as a possible cause of depression.
However, researchers have not definitively determined that vitamin D deficiency causes depression, although the two are linked. One large population-based study found an association between vitamin D status and depression in middle-aged adults.
The results of the study suggest that vitamin D deficiency and insufficiency may help identify adults who are at increased risk of developing depression. Deficiency can also serve as a biomarker for people with depression whose symptoms persist despite treatment, meaning that monitoring deficiency levels can help diagnose depression and monitor treatment progress.
Depression is a mood disorder that affects how a person feels, thinks and copes with everyday activities, such as sleeping, eating or working. People who have depression often experience one or more of the following symptoms almost every day for at least two weeks:
- Sadness and anxiety
- Loss of interest or pleasure in activities or hobbies
- A feeling of hopelessness
- Irritability, frustration or restlessness
- A feeling of helplessness or worthlessness
- Fatigue or loss of energy
- Difficulty concentrating or making decisions
- Sleep that lasts too long, too often or not enough sleep
- Changes in appetite or weight
- Physical pain, headaches, cramps or digestive problems
- Thoughts of death or suicide
Everyone who is depressed experiences this condition differently and will not have all of the above symptoms. If you or someone you love is showing signs of depression, get in touch National Substance Abuse and Mental Health Services Helpline (SAMHSA). at 1-800-662-4357 for information about support and treatment facilities in your area.
Several small studies have found that people who are depressed experience improvements in their symptoms after they start taking vitamin D supplements.
However, other research shows that vitamin D supplementation does not affect symptoms of depression. For example, a large study of more than 18,000 people with depression found that taking 2,000 international units (IU) of vitamin D per day for five years did not change depression scores compared to taking a placebo. Several other studies have reached similar conclusions.
It is important to note that vitamin D is not included in the guidelines for the treatment of mood disorders. Most scientists agree that more research is needed to determine the effectiveness of vitamin D for depression, as well as what blood levels are needed and how to replenish them when a person is depressed.
If you have depression and suspect your vitamin D levels are low, the best thing you can do is talk to your healthcare provider. They may order a blood test to determine your vitamin D status. This will give you a baseline measurement of your vitamin D levels before you start supplementing.
If you can’t afford testing, you may be able to take supplements without testing as long as you stay within the recommended daily intake of vitamin D, which is 600-800 IU for adults. Some health experts think taking vitamin D without testing is safe, especially if you know you don’t get enough sunlight or eat fortified foods.
Your exact vitamin D needs are based on your age, health and skin color; Non-Hispanic black Americans, women, and people aged 20-29 are particularly at risk of vitamin D deficiency.
When taking vitamin D, be careful about how much you take in and avoid taking too much. Because vitamin D is fat soluble, it has the potential to accumulate in your system and can lead to vitamin D toxicity.
People with vitamin D toxicity can develop kidney stones (clusters of minerals in the urine that are difficult and painful to pass through the urinary tract). Other symptoms include:
- Nausea
- Vomiting
- Confusion
- Pain
- Dehydration
- Muscle weakness
- Loss of appetite
- Extreme thirst
- Excessive urination
Extremely high levels of vitamin D can cause irregular heartbeat, kidney failure, and death.
Vitamin D toxicity is almost always caused by supplementation. You can’t get too much vitamin D from the sun. Your skin naturally limits the amount of vitamin D it produces from the sun.
Research shows that symptoms of vitamin D toxicity are most likely to occur when your daily intake is at least 10,000 IU. However, amounts less than the tolerable upper intake level of 4,000 IU can also have a negative impact over time.
Vitamin D supplements may interact with some medications, including diuretics, statins, steroids, and Orlistat (a weight loss drug). Some of these drugs may also increase the risk of vitamin D toxicity. Talk to your healthcare provider before taking vitamin D supplements if you are taking any other medications or supplements.
Research shows a link between depressive symptoms and vitamin D deficiency. People with depression are more likely to be deficient in vitamin D, and vitamin D deficiency can increase the risk of depression.
However, research is not clear on whether vitamin D supplementation can reduce symptoms of depression. If you have symptoms of depression and are considering taking vitamin D, talk to your healthcare provider about your options.