By Julie Starkel, MS, MBA, RD

This time of year is awfully dark in the Pacific Northwest. As many of you know, one of the greatest ways to get vitamin D is by exposing our skin to sunlight. In this climate, there is not enough sunlight for our bodies to produce vitamin D between approximately October and March. Our bodies cannot store vitamin D over such a long period of time. What can we do to boost vitamin D during these winter months?

Let’s begin with an explanation of the importance of vitamin

D. Vitamin D regulates calcium and phosphorus levels in our blood by regulating absorption of these minerals from food in our intestines. While also important for bones, calcium is important for muscle contraction. Vitamin D promotes bone formation and mineralization, which is essential for kids and adults alike in maintaining strong skeletons. It affects anti-tumor activity, and newer research has shown that vitamin D deficiencies are linked to colon cancer. There is some evidence, although conflicting, that deficiencies are linked to other cancers as well. Additionally, there are also strong implications that a vitamin D deficiency is linked to several autoimmune diseases such as MS, lupus, or Hashimoto’s (autoimmune hypothyroidism). Interestingly, there are higher rates of autoimmune disease in the northern states of the US, and people with darker skin who live in the northern latitudes have even higher rates of these diseases than the average person in these areas. The theory is that darker skin requires more sunlight to synthesize the active form of vitamin D. If you have not already, you will hear much more about vitamin D in the years to come.

During the summer, if we expose our body to the sun in small increments, our skin converts a cholesterol compound already present in our bodies to the active form of vitamin D for our bodies to use in various reactions in the body. Wearing sunscreen prevents this process, so it’s helpful to spend some time in the sun before applying sunscreen. In the winter, most of us have to find sources other than sunlight.

Unfortunately, very few foods are high in vitamin D. I guess nature intended for us to live in sunnier climates! Most of us, therefore, get our vitamin D through fortified foods. Fortified foods are foods to which manufacturers add vitamins and minerals. The most well known vitamin D fortified food is milk. Most organic brands also add vitamins A and D. Other foods with added vitamin D are some soy milks and cereals. Be sure to read the labels to verify it is added.

How much vitamin D should we consume? Although the US Recommended Daily Intakes suggest a minimum of 200 IU/day for children and adults through age 50, this may be too low by a factor of 3 for northern climates. Many health care practitioners I work with never recommend less than 600 IU and very often suggest up to 2000 IU. The only reliable way to assess someone’s vitamin D level is to do a blood analysis. Ask your physician or nutritionist what is best for you.

The best, most reliable, source of vitamin D in my opinion is cod liver oil. My favorite brand is Carlson’s. In independent analyses, they tested negative for mercury contamination and positive for pleasant taste. They have orange and lemon (my favorite) flavors. One tablespoon provides about 1200 IU, and kids can take less. Get creative in how you take it. One way is to mix it in with some raspberry kefir or yogurt. The kids I know like it! There are also omega-3 fatty acids in fish oils, which is a great benefit of getting your vitamin D from fish oil. Pregnant women should consult their doctor before taking cod liver oil supplements.

There are a few foods that supply vitamin D. These include the following:

• Salmon, 3.5 oz., 360 IU vitamin D
• Catfish, 3 oz., 425 IU vitamin D
• Shrimp, 3 oz., 150 IU vitamin D
• One egg 20 IU vitamin D

It is well worth your effort to make sure you are getting sufficient amounts of vitamin D in your diet during the winter. The evidence of it being important to our overall, long-term health is mounting. So, get outside on the rare sunny days and enjoy a healthy spoonful of fish oil every day this and every winter – until you move to Hawaii, of course!

Julie Starkel, MS, MBA, RD is a whole foods Clinical Nutritionist and Registered Dietitian, who sees clients at Green Lake Nutrition, located in Kirkland and Seattle, Washington. She has a Master of Science degree in Nutrition from Bastyr University and a background of over 10 years in health and fitness. She’s a member of the American Dietetic Association, the Nutrition in Complementary Care dietetic practice group, the Institute of Functional Medicine, and has worked in both the traditional and natural medicine arenas in Chicago and Seattle. See her website, e-mail her, or call 206-465-3469.

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