Vitamin D is essential to help build strong bones and teeth. It helps your body absorb and use calcium. It also helps your body maintain a normal level of phosphorus. Without vitamin D, bones can become thin, brittle, or misshapen. Vitamin D prevents rickets in children and osteomalacia in adults. These are 2 forms of skeletal disease that weaken bones.
Sources of vitamin D include:
Foods that naturally contain vitamin D. The best food sources of natural vitamin D are fatty fish, such as salmon and tuna. Beef liver, egg yolks, cheese, and mushrooms also have small amounts of vitamin D.
Foods fortified with vitamin D. These include cereals, milk, and soy or other milk beverages. But read labels – many dairy foods made from milk, such as cheese and ice cream, are not fortified with vitamin D.
The rays of the sun. Ultraviolet B rays help your body make vitamin D. Sunshine is the way most people get all the vitamin D they need each day.
The current advice from the Food and Nutrition Board for daily vitamin D intake is:
Birth to 12 months: 400 International Units (IU)
Ages 1 to 70: 600 IU
Age 71 and older: 800 IU
You may be at risk for a deficiency of vitamin D if:
You don't get enough vitamin D in your diet
You don't get out in the sun
Your kidneys can't convert vitamin D to the form your body needs
Your body can't adequately absorb vitamin D
You are obese. Body fat binds to some vitamin D and keeps it from getting into the blood.
Older adults also have problems making enough vitamin D. This is because older skin is less efficient at using the sunshine. In fact, older Americans are at highest risk for vitamin D deficiency. They also often don't eat enough foods that contain vitamin D. And they may take medicines that interfere with the body's production of the vitamin.
You don't need to be out in the sun long to get enough sunlight to help your body make vitamin D. You'll get enough if you spend 10 to 15 minutes outdoors between 8 a.m. and 4 p.m. 2 to 3 days a week. The sunlight stimulates a hormone in your body to make vitamin D.
Unfortunately, even if you spend the right amount of time outdoors, you can't always get enough sunlight. In many parts of the country, the sun doesn't shine intensely enough in the winter months to help make vitamin D.
Cloud cover, air pollution, altitude, and a person's skin color also affect the amount of sunshine available to the body. Sunscreens can also block the amount of sunshine that affects the skin.
Don't take a vitamin D supplement until you have discussed it with your health care provider. Too much vitamin D can be toxic.