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It’s no secret that winter is one of the gloomiest times of the year in Seattle, with short days and little sunlight, which is why if you live in the Pacific Northwest, it’s likely you are not getting a sufficient amount of vitamin D.

Our bodies naturally synthesize vitamin D when exposed to sunlight. All you need for a week’s worth of vitamin D is 15 to 20 minutes in the sun. During the winter months in Seattle, even that can be hard to come by.

Vitamin D helps the body absorb calcium, which supports the development and maintenance of healthy bones. Insufficient amounts of it, especially in children, can cause a condition called rickets, a softening of the bones, making patients more prone to fractures and deformities. For older people, vitamin D and calcium are important in preventing osteoporosis, or brittle bones.

While we’ve known about the connection between vitamin D and calcium for some time, more recent research has shown that vitamin D may also improve muscle recovery and help prevent soreness and aching.

Research has also shown that vitamin D may help with immune function and may improve depression symptoms and help alleviate symptoms of seasonal affective disorder (SAD). Sunlamps can also help with symptoms of SAD, but they do not provide the body with vitamin D.

You can get small amounts of vitamin D from foods including fish, eggs and fortified milk, but for people living in the Seattle area, it’s hard to get enough vitamin D without taking a supplement.

I recommend to my patients that they take a daily vitamin D supplement with 1000 to 2000 international units (IU) to ensure sufficient vitamin D levels.

The Institute of Medicine recommends a minimum daily allowance of 600 IU of vitamin D per day and 800 IU per day for people over age 70. People living in the Pacific Northwest may need more than this due to our limited exposure to the sun compared with other areas of the country, particularly during winter.

During the summer months, when the sun does come out in Seattle, it is easier to get those 15 to 20 minutes of sunshine per week. However, keep in mind that sunscreen blocks the UV light
that allows our skin to synthesize vitamin D.

I don’t advise going into direct sunlight for extended periods of time without sunscreen, especially for those who are fair skinned or have other risk factors for skin cancer. For this reason, it may be worthwhile to take vitamin D supplements all year round.

Some people are more susceptible to low vitamin D than others. People with darker skin tones need more sunlight to synthesize enough vitamin D. Older populations should also be aware of vitamin D levels to ensure bone health. Breast-fed infants are also prone to vitamin D deficiency because breast milk does not usually contain a sufficient amount of vitamin D and infants should not be exposed to direct sunlight.

Seattle’s latitude and propensity for cloudy days make it hard for all of us to get enough vitamin D, so if you’ve got the rainy-day blues and aren’t already taking vitamin D, you might want to consider a supplement to boost your vitamin D.

Lisa Sieberson practices family medicine at Pacific Medical Centers’ Northgate and Lynnwood clinics. She earned her doctor of nursing practice degree from the University of Washington.

Pacific Medical Centers is a private, not-for-profit, multi-specialty health care network of nine clinics in Beacon Hill, Canyon Park, Federal Way, First Hill, Lynnwood, Northgate, Puyallup, Renton and Totem Lake.