Lack of vitamin D linked to winter blues
New research has found that vitamin D deficiency may be responsible for the onset of sesaonal affective disorder (SAD)--a form of depression that usually occurs in the fall and winter.
Previous research has suggested that SAD may be caused by disruption of the body's internal clock or an imbalance of mood-regulating hormones, both of which have been associated with a reduction in sunlight exposure.
In the new study, scientists from the College of Education at the University of Georgia said that vitamin D deficiency may be the root cause. They first noted that levels of naturally-occurring vitamin D in the body change according to the season and sunlight exposure. They found that it typically takes eight weeks for the body develop SAD after sunlight exposure starts to decrease.
The researchers then noted that vitamin D plays an important role in the body's production of the mood-regulating hormones dopamine and serotonin, which they said suggests that there may be a relationship between low vitamin D levels and depressive symptoms.
Lastly, the researchers found that people with darker skin pigmentation may be at higher risk of vitamin D deficiency, particularly if they live in areas with high altitudes.
The new research, published in the journal Medical Hypotheses, suggests that there is strong reason to believe that maintaining adequate levels of vitamin D is important for good mental health, especially in the winter months. Researchers suggested that people should try to get at least a few minutes of sunlight exposure every day to prevent low vitamin D levels.