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Stay ahead of Seasonal Affective Disorder (SAD) this winter with Vitamin D

Vitamin D, frequently referred to as the “Sunshine Vitamin”, has recently been linked to mental health. The reason for the connection is that Vitamin D is a neurosteroid that has the ability to interact with brain receptors (Harms, et al. 2011). Because of this, Vitamin D may play a role in normal brain function and neurodevelopment.

The sun is a major source of Vitamin D during the summer months but does not provide adequate Vitamin D during the winter.

Multiple studies have linked deficiency in Vitamin D to depressed mood. Researchers have found Vitamin D receptors on cells located in regions in the brain linked with depression. Seasonal Affective Disorder (SAD), a mood disorder with depressive symptoms, occurs during the dark winter times of the year when there is relatively little sunshine and coincides with a drop in Vitamin D levels in the body. Several studies have suggested that the symptoms of SAD may be due to changing levels of Vitamin D, which may affect serotonin levels in the brain (Berk et al., 2007).

Currently, it is unclear if associations between Vitamin D deficiency and mental illness are causative or circumstantial. Does the depressed person become deficient because they spend less time outdoors and thus intake less Vitamin D? Or does the Vitamin D deficiency cause the person to be depressed? Still, there is some evidence for symptom improvements with Vitamin D supplementation. If Vitamin D does have an effect on mental illness, it is likely a modest one and treatment with Vitamin D would most likely be in parallel to other treatments (Greenblatt, 2011).

Surprisingly, about 1 billion people in the world are deficient in Vitamin D. Deficiency is more likely in individuals living far from the equator, those with dark skin, the elderly, and those with chronic diseases that interfere with the activation of Vitamin D. In most of the United States, it is almost impossible to get enough vitamin D from the sun during winter due to lower sunlight intensity and duration and more skin coverage.

Whether or not you are feeling gloomy, it is important to get your Vitamin D levels checked regularly for two reasons:

1.) Your Vitamin D levels can change with the seasons and variations in diet and supplementation. So even if your levels were fine last summer, you may be deficient after the long winter.

2.) As a hormone, Vitamin D plays a role in many parts of your body. Even if your mood seems fine, an unknown Vitamin D deficiency could be wreaking havoc on your bone density, weakening your immune system and muscles, and increasing your risk for cancer and heart disease.

For Recommended Dietary Allowances (RDA) and a list of foods high in Vitamin D, visit this web page:


Berk, M., Sanders, K.M., Pasco, J.A., Jacka, F.N., Williams, L.J., Hayles, A.L., & Dodd, S. (2007). Vitamin D deficiency may play a role in depression. Medical Hypotheses, 69 (6): 1316-1319.

Greenblatt, J.M. (2011). Psychological consequences of vitamin D deficiency: Vitamin D supplementation may help depression. The Breakthrough Depression Solution Integrative medicine for mental health. North Branch, MN: Sunrise River Press.

Harms, L.R., Burne, T.H.J., Eyles, D.W., & McGrath, J.J. (2011). Vitamin D and the brain. Best Practice & Research Clinical Endocrinology & Metabolism, 25, 657–669


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