Low Vitamin D Linked to Depression
Vitamin D Basics
Vitamin D comes in two basic forms, known as vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Only a limited number of foods contain these substances, the National Institutes of Health’s Office of Dietary Supplements explains. Examples of these foods include mackerel, salmon, tuna, various types of fish oil, egg yolks, mushrooms, cheese and beef liver. Food manufacturers commonly add supplemental vitamin D to a variety of foods, including items such as orange juice, milk and cereal. In addition to these natural and fortified foods, the main source of vitamin D for most people is sunshine, which contains a form of light called ultraviolet light. When ultraviolet light hits the skin, it starts a chemical process in the body that ultimately results in production of the vitamin. Many people augment their daily supply of the vitamin with either standalone supplements or vitamin D-containing multivitamins.
Vitamin D Deficiency
Between the ages of 1 and 70, the average person needs to get 15 micrograms of vitamin D each day, the U.S. National Library of Medicine reports. Newborns and infants need less than this amount, while people over the age of 70 need slightly more. Any given individual can develop a vitamin D deficiency if he or she doesn’t consume enough of the vitamin for extended periods of time, has difficulty properly absorbing the vitamin D content of consumed foods or drinks, doesn’t get enough safe sun exposure, or doesn’t create the vitamin properly after sun exposure. Other potential underlying causes of a deficiency include strict adherence to a vegan or ovo-vegetarian diet, intolerance to a sugar in dairy products called lactose, and the presence of a milk allergy.
Links to Depression
In a study published in 2012 in the journal Mayo Clinic Proceedings, a multi-institution research team used information gathered from 12,600 individuals over a period of four years to examine the links between vitamin D levels and the symptoms of major depression. After reviewing their data, these researchers concluded that people with low levels of vitamin D in their bodies have an unusually high chance of developing major depression symptoms, especially when they have previous histories of such symptoms. Conversely, people with higher-than-average vitamin D levels typically have substantially diminished chances of developing major depression symptoms; risks are especially reduced in individuals with a past depression history.
In another study, presented in 2012 at the annual meeting of the Endocrine Society, researchers from Delaware’s Bayhealth Medical Center examined the effects of vitamin D supplementation on the mental health status of three women previously diagnosed with severe major depression. All of these women had significant deficiencies of the vitamin before receiving the supplements. In a period of two to three months, supplementation allowed all of the study participants to return their vitamin D levels to the normal range. After their levels for the vitamin returned to normal, all three women experienced a substantial decline in their depression symptoms and moved from a severely depressed state to a minimal or moderately depressed state.
No one really knows how vitamin D levels affect depression, the authors of the study in the Mayo Clinic Proceedings report. In addition, no one knows if the presence of depression can lead to a reduction in an affected individual’s vitamin D levels. The authors of the study presented to the Endocrine Society echo these statements, and also note the need for continuing, large-scale research to truly describe the underlying connections between depression and vitamin D status. As a result of the current limitations on scientific understanding, neither of these studies fully recommends that doctors use vitamin D supplements as a treatment for depression. However, they do recommend the use of vitamin D screening in patients with high depression risks. People affected by depression should never change their current treatment plans without explicit advice from their doctors.