Vitamin D Supplements & Depression

According to the National Institute of Mental Health, clinical depression affects almost 15 million American adults. A PBS documentary titled "Depression: Out of the Shadows," said that 4 percent of adolescents develop serious depression each year, and by the year 2020, it will become the second most common health problem in the world. While the NIMH says that there are many causes of depression -- physical abuse, substance abuse, illness, genetics or personal problems -- there is one cause that has been shown to not only have a direct correlation to the disease but can be part of a definitive cure: vitamin D.

Depression Causes

Studies have shown that a vitamin D deficiency is directly responsible for depression in adults and in particular older adults. A Reuters article described such a study conducted by the National Institute of Aging in Baltimore in which more than 900 men and women age 65 and older were examined for depression and levels of vitamin D. The study found that 42 percent of the women tested and 18 percent of the men were depressed and of that number, 3/4 of the women and half of the men also had vitamin D levels below 50 nanomoles per litre, which is considered insufficient. In another study, this one done by Dutch researchers and reported in the Archives of General Psychiatry, low levels of vitamin D, along with high levels of hormones secreted by the parathyroid gland, was found to possibly increase the risk of depression in older adults.

Vitamin D

Vitamin D is a steroid vitamin that promotes the body's absorption and usage of calcium and phosphorous. Many people get a sufficient amount of vitamin D from the exposure to the sun, through UV rays absorbed by the skin. However, decreased exposure to the outdoors and decreased dietary consumption can bring about low vitamin D levels. Low vitamin D levels cause the parathyroid glands to secrete high levels of hormones that may bring on depression.

Sunlight

When it comes to obtaining vitamin D from the sun, doctors at the National Institutes of Health say that location and time of year, among other factors, play a role in the amount of vitamin D that is absorbed by the body. The researchers, for instance, state that the area above 42 degrees north latitude produces insufficient levels of vitamin D from November to February. Also, complete cloud coverage cuts the amount of vitamin D available by nearly 50 percent. Glass, the researchers add, does not allow the sun's UV rays to penetrate, so exposure to the sun indoors does not supply the body with vitamin D.

Amount

As a general rule, doctors at NIH recommend approximately five to 30 minutes of exposure to the sun on the face, arms, back and legs without sunscreen between 10 a.m. and 3 p.m. twice weekly to get a sufficient amount of vitamin D.

Food

In addition to obtaining vitamin D from the sun, people suffering from depression may also receive vitamin D from various food and vitamin supplements. Although few foods contain vitamin D, some of the best sources are fish -- salmon, tuna or mackerel -- fish oils, beef liver, egg yolks and cheese. Also, some mushrooms contain a form of vitamin D as well. Vitamin D is also found in fortified foods, such as most milk in the U.S., some breakfast cereals and calcium fortified juice drinks.