Why Should You Care?

When mentioning Vitamin D, many people think of bone health, but the “sunshine vitamin” actually plays an important role in cardiovascular, immune system, musculoskeletal, and brain health. Deficiencies can attribute to the development of cancer, Type 2 diabetes, and respiratory infections, among other things.

Vitamin D is actually a hormone, not a vitamin. Generally, we get vitamins from the foods we eat, but our bodies can make Vitamin D, along with other hormones.

How Do You Know If You Are Deficient?

Most people are actually deficient in Vitamin D. To determine your status, ask your doctor to order you a Vitamin D, 25 Hydroxy blood test. Health care professionals generally recommend that you maintain Vitamin D levels of 50-70 ng/mL (recommended ranges vary slightly).

What Do You Do If You Are Deficient?

There are three ways to increase your Vitamin D levels: food, supplements, and sunlight exposure.


Very little of your Vitamin D comes from dietary sources. This is because Vitamin D is naturally present in very few foods. Those high in Vitamin D include: salmon, eggs, tuna, halibut, sardines, trout, cod liver oil, and fortified dairy products. However, you would have to eat large quantities of these foods daily to get the amount of Vitamin D you need, so it’s pretty much impossible to maintain normal levels from diet alone.

Sun Exposure

This is a great way to increase your Vitamin D levels, if you do it correctly. Your body makes Vitamin D when UVB rays shine on exposed skin. (UVA rays increase your risk of skin cancer and sun damage.) You can safely optimize your Vitamin D levels by using what Vitamin D expert, Dr. Michael Holick, calls “sensible sun exposure.” To do this, start by limiting your sun exposure to a few minutes for the first few days (longer if you have darker skin). Gradually build up to about 15-20 minutes per day for two to three days per week. Here are some additional things to keep in mind:

  • Expose your arms, legs, and back without sunscreen;
  • Always protect your face and eyes, since these areas (1) don’t really contribute much to vitamin D production and (2) are more susceptible to premature wrinkling and sun damage;
  • If you stay in the sun longer than 15-20 minutes, protect your skin in some way (i.e., healthy sunscreen, clothing, etc.)
  • Never allow your skin to burn – staying in the sun longer does not cause your body to make more Vitamin D and increases your risk of sun damage and skin cancer;
  • Sunscreens almost completely prevent your body from making Vitamin D;
  • You don’t make Vitamin D when you are exposed to sunlight through a window (i.e., in your car or home) because the UVB rays can’t penetrate the glass; and
  • The amount of sun exposure you need depends on several factors, including the season, time of day, and where you live;

Unless you live near the equator, there are several months when you won’t be able to get Vitamin D from the sun. During these times, it may be necessary to take Vitamin D supplements.


If you decide to take a Vitamin D supplement, make sure you take Vitamin D3 (the active form, cholecalciferol) and not Vitamin D2 (the inactive form). The dosage you should take depends on your health status, and should be discussed with a qualified health care professional.

While your body self-regulates Vitamin D levels from sun exposure, it is possible (though not likely) to increase your Vitamin D levels to abnormally high levels from taking supplements. Vitamin D is fat soluble, so your body can store extra amounts. So, if you take more than 5,000 IU daily, make sure your health care provider monitors your Vitamin D blood levels about every two to three months. Also, when supplementing with Vitamin D, make sure your Vitamin K levels are also normal. Without going into detail, these two vitamins interact, particularly with respect to bone and heart health.