Vitamin D deficiency is when you do not have enough vitamin D in your body. This is a problem, because the body needs vitamin D to absorb calcium and for other important jobs.

People who do not have enough vitamin D can:

Have weak or soft bones, which can break easily or change in shape

Have weak muscles, which makes them more likely to fall

Is there a test for vitamin D deficiency? Yes. Your doctor or nurse can do a blood test to see if you have enough vitamin D. But you might not need this test. Doctors measure vitamin D levels only in people who are at risk for vitamin D deficiency. This includes people who:

Spend most or all of their time indoors

Have medical problems that make it hard for them to absorb vitamin D

Have a condition called “osteoporosis,” which makes bones weak

Broke a bone too easily, such as by falling down

What foods and drinks have vitamin D? Foods and drinks that have a lot of vitamin D include:

Milk, orange juice, or yogurt with vitamin D added

Salmon or mackerel

Canned tuna fish

Cereals with vitamin D added

Cod liver oil

People’s bodies can also get vitamin D from the sun. The body uses sunlight that shines on the skin to make vitamin D.

What are supplements? Supplements are pills, capsules, or liquids that have nutrients in them. Supplements are another way people can get vitamin D.

Do I need to take vitamin D supplements? Experts recommend that most adults take supplements that have 600 to 800 international units of vitamin D a day. This is the same as 15 to 20 micrograms of vitamin D. People who do not get enough vitamin D from their food or from the sun might need to take even more.

If your doctor recommends that you take vitamin D supplements, ask him or her which type, how much, and when to take the supplements.

The type and dose of supplement that is right for you will depend on your medical problems and the other medicines you take.

It is important not to take too much vitamin D. Taking too much vitamin D can make you sick.

Can I get extra vitamin D from the sun? It is not a good idea to try to get vitamin D by spending time in the sun or using tanning beds. This can lead to sunburn and increase your risk of skin cancer.