Vitamin D: Winter Update

As we are now squarely in the winter season; the daylight hours are shorter; the weather is colder; and the end of the quarter – accompanied by all of its stress – is here. Seattle has one of the lowest rates of clear skies in the country, with clear skies occurring only about 28% of the time during the winter months. Furthermore, many people in the Pacific Northwest experience Seasonal Affective Disorder, which has symptoms similar to depression. Signs and symptoms include: fatigue, low energy, increased appetite, and feeling sad or down.


One common explanation for changes in mood during the winter is reduced direct sunlight. It can be hard to find time to get outdoors in the winter, which in turn can impact the amount of Vitamin D we get from sunlight. Although the link between Vitamin D and problems with mood is not fully understood, there does seem to be evidence that Vitamin D is related to levels of serotonin in the brain. When we get less exposure to sunlight, thus getting less Vitamin D, our serotonin levels also go down. Lower serotonin is generally related to increases in depression. In fact, many medications that are used to treat depression target serotonin levels.

While increasing Vitamin D levels doesn’t help everyone improve their mood, many people do report benefits. There are several ways to make sure we get adequate Vitamin D when our access to sunlight is limited:

  • Try getting small amounts of sunlight throughout your day. When it’s not raining, consider going for a short walk during lunch or between meetings and classes. All of the smaller amounts can add up to help you get enough exposure to the UVB rays.
  • Eat foods that are high in Vitamin D. Fatty fish, like salmon, eggs, fortified milk, orange juice, cheese, and mushrooms all contain large amounts of Vitamin D.
  • Some experts recommend using sun lamps or light boxes that produce a full-spectrum bright light to increase Vitamin D. These lights that are made for light therapy don’t increase risk for skin cancer, unlike tanning beds.
  • Vitamin D supplements have mixed evidence in terms of improving mood. At this point, research does not clearly indicate that taking Vitamin D supplements improves mood.

If you are someone who typically starts feeling down during the winter, it may help to start adding some of the tips above into your day. Exercise, whether indoors or outside, also has been consistently shown to improve mood. If none of these tips work for you, consider reaching out for help from friends or family, your church community, or a mental health therapist.

Update (4/2018): Check out this comprehensive and useful guide for how to get a good night's sleep!

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