Functions

The main function of vitamin D is to maintain normal calcium and phosphorus levels in the blood. This nutrient helps the gut absorb calcium, and is needed for healthy bone growth. However, that’s not all vitamin D does to keep your body running.

People who don’t have sufficient vitamin D levels may have an increased risk of osteoporosis, rickets, cardiovascular disease, asthma and cognitive impairment. Vitamin D also regulates the immune system, reduces your risk of multiple sclerosis and cancer and may help people recover from tuberculosis more quickly.

Sources

The main way people get vitamin D is through sun exposure. When you're outdoors, your body produces vitamin D in response to sun exposure.

Vitamin D can also be found in fortified milk and orange juice, salmon, tuna fish, yogurt, eggs and cheese. Many individuals take vitamin D supplements to help increase their levels. 

Daily Value

It is recommended that infants get 400 international units (IUs) of vitamin D a day. After that, people should get between 600 and 800 IUs of vitamin D until age 70, and over that age they need 800 IUs each day.

To understand what it takes to get between 600 and 800 IUs of vitamin D, an 8-ounce glass of milk has 100 IUs, while 3 ounces of salmon has about 550 IUs. 

Types

While there are five types of vitamin D, the one that is most important for human health is vitamin D3, also known as cholecalciferol.

Find out more about vitamin D:

Shedding Some Light on Vitamin D: The Sunshine Vitamin

Are You in Dairy Danger? 

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