New evidence from a
small study suggests that vitamin D supplements may improve symptoms of seasonal
affective disorder (SAD), a pattern of depression related to changes in seasons
and a lack of exposure to sunlight.
SAD usually occurs during the winter months and may cause headaches, irritability and a low energy level. It is unclear exactly what causes SAD, although disruptions in the circadian rhythm and abnormal levels of melatonin, serotonin and vitamin D have all been suggested as potential contributors.
During the winter
months, many people are exposed to less sunlight, and sunlight helps the body
make vitamin D3. Therefore, some researchers have suggested that vitamin D
deficiency may play a role in SAD.
The study, published
in the journal, Applied Nursing Research, included nine women
who had borderline-low serum vitamin D levels (less than 40 nanograms per
milliliter of blood) during the winter months. Six of these women completed questionnaires
about their SAD symptoms before and after supplementation with 5,000
international units of vitamin D3 daily.
The researchers found
that vitamin D supplementation was linked to an increase in serum vitamin D
levels by an average of 27 nanograms per milliliter of blood and a significant
improvement in SAD symptoms.
"This pilot study provides evidence to suggest that women who suffer from seasonal depressive symptoms may benefit from vitamin D3 supplementation if serum vitamin D levels are low," the authors concluded.
Although these early results are promising, this study is limited by its small sample size.
For more information about vitamin D, please visit Natural Standard’s Foods, Herbs & Supplements database.