A nickname for vitamin D is the "sunshine vitamin." That's because your body uses sunlight to help make vitamin D. Exposing your skin to ultraviolet rays from the sun changes a type of cholesterol in your skin to vitamin D. However, getting enough sunshine can be a problem if you live where winters are cold. Getting sun through a window does not work.
The recommended daily dose of vitamin D for most people is about 600 international units (IUs). For your body to make enough vitamin D:
- You need to get 5 to 30 minutes of sun between 10 in the morning and 3 in the afternoon.
- You need to get this much sun at least twice a week.
- The sun should be shining. On a cloudy day, you need to be out twice as long.
Not everyone can get this amount of sunshine, especially in the winter. You also risk overexposure to UV light and skin damage over time. But, there are other ways to get vitamin D.
Vitamin D from Your Diet
It can be hard to get 600 IUs of vitamin D a day because the vitamin does not occur naturally in many foods. But, it has been added to some others. These products usually say "vitamin D fortified" on the label.
Consider adding the following foods to your diet. The IUs listed are the amount you would get from one serving:
- Swordfish: 566 IUs
- Salmon: 447 IUs
- Canned tuna: 154 IUs
- One egg: 41 IUs
- Vitamin D-fortified orange juice: 137 IUs
- Fortified breakfast cereal: 40 IUs
Some yogurts and margarines may be fortified with vitamin D. So is milk. Vitamin D is also found in sardines, liver and beef.
Also, fish oil is very high in vitamin D. A tablespoon of cod liver oil will give you about three times the amount of vitamin D you need for the day. It can be difficult to swallow fish oil. You might try mixing it with a small amount of something more tasteful, such as juice.
Vitamin D from Supplements
Some people might not get enough vitamin D from sunshine and diet. That's especially true in the winter. Then, you might need to add a vitamin D supplement.
For most adults, a supplement of 600 IUs will give you all the vitamin D you need. If you are older than 70, you might need 800 IUs. Vitamin D supplements come as D2 and D3. Either one will get your vitamin D level up.
Of course, it's best to check with your doctor to find out the amount that's right for you. Also, vitamin D supplements can interfere with some medications. That's another reason to talk with your doctor before adding a supplement. A blood test can determine your vitamin D levels.
People who have a vitamin D deficiency usually need supplements. Some people are more likely than others to have this problem. They include:
- Women who are pregnant or breastfeeding
- Anyone older than 70
- People with dark skin (dark skin makes it harder for the body to use sunlight to help make vitamin D)
- People who are lactose intolerant and don't drink fortified milk
- Anyone who's overweight (body fat keeps vitamin D from being absorbed into the blood)
Why Worry About Vitamin D
Vitamin D is a very important vitamin. You need this vitamin all year long—not just when it's warm and sunny and nice to be outside.
Vitamin D helps you absorb calcium. Calcium is important for healthy bones. Vitamin D also helps your muscles and nerves stay healthy and work like they should. Without vitamin D, your nerves could not tell your muscles when to move. Vitamin D also helps your body’s immune system fight off infections from germs.
If you’re at risk of a vitamin D deficiency or would like to know how your levels compare to a normal reference level, ask your doctor to order a vitamin D blood test.
