Vitamin D is an essential nutrient you mainly get from sun exposure. If you don’t get enough of it, some research suggests you could be at a higher risk of experiencing depression. However, research on whether supplementing with vitamin D can relieve depressive symptoms is mixed.
Vitamin D deficiency is common—affecting about 35% of adults in the United States—and is associated with several health problems.
For instance, lack of vitamin D is linked to 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 determined definitively that vitamin D deficiency causes depression, though the two are linked. One large population-based study found an association between vitamin D status and depression in middle-aged adults.
The study results suggest that vitamin D deficiency and insufficiency may help identify adults who are at an increased risk of developing depression. Deficiency may also serve as a biomarker for people with depression whose symptoms persist despite treatment, meaning monitoring deficiency levels may help with depression diagnosis and tracking treatment progress.
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 causing bones to soften, leading to bone pain, muscle weakness, and bone deformities like rickets.
However, vitamin D’s role is not limited to bone health. It also has anti-inflammatory, antioxidant, and brain-protective properties and supports several other bodily functions.
For instance, having adequate amounts of vitamin D can boost your immune system’s ability to fight off viruses and other germs. Your muscles rely on vitamin D to move, and your nerves utilize vitamin D to send messages between your brain and your body.
Depression is a mood disorder that affects how a person feels, thinks, and handles daily activities, such as sleeping, eating, or working.
People who have depression often experience one or more of the following symptoms nearly daily for at least two weeks:
- Sadness and anxiety
- Lost interest or pleasure in activities or hobbies
- Feelings of hopelessness
- Irritability, frustration, or restlessness
- Feelings of being helpless or worthless
- 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 aches or pains, headaches, cramps, or digestive problems
- Thoughts about death or suicide
Everyone who is depressed experiences this condition differently and will not have every symptom listed above. If you or someone you love is showing signs of depression, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on 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 supplementing with vitamin D does not affect symptoms of depression. For example, a large study including more than 18,000 people with depression found that taking 2,000 international units (IU) daily of vitamin D for five years did not change depression scores compared with taking a placebo. Several other studies came to similar conclusions.
Vitamin D is not included in the guidelines for treating mood disorders. More research is needed to determine the effectiveness of vitamin D for depression, as well as what blood levels are needed and how to supplement when a person is depressed.
If you have depression and suspect that your vitamin D levels are low, the best thing you can do is to talk with a 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 begin supplementation.
If you cannot afford testing, you may be able to supplement 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 maintain that taking vitamin D without testing is safe, especially if you know you aren’t getting adequate sunlight or eating fortified foods.
Your exact vitamin D needs are based on your age, health status, and skin color; non-Hispanic Black Americans, women, and people 20-29 years old are particularly at risk for vitamin D deficiency.
When taking vitamin D, be aware of how much you consume and avoid taking too much. Because vitamin D is fat-soluble, it has the potential to build up in your system and can result in vitamin D toxicity.
People with vitamin D toxicity may develop kidney stones (mineral clusters in 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 vitamin D levels may cause irregular heartbeat, kidney failure, and death.
Vitamin D toxicity is almost always caused by supplementation. You cannot get too much vitamin D from the sun. Your skin naturally limits the amount of vitamin D it makes from sunshine.
Research indicates 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 could 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 medications can also increase your risk of vitamin D toxicity. Talk to a healthcare provider before taking vitamin D supplements if you are taking any other medications or supplements.
