Vitamin D: How much do I need?

How much vitamin D do I need?

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Mayo Clinic dietitian Katherine Zeratsky, R.D., L.D., and colleagues answer select questions from readers.

Answer

This is a good question without a simple answer.

It has long been known that vitamin D is crucial for healthy bones. Some research also suggests that vitamin D may play a role in preventing certain cancers and autoimmune diseases.

The National Academies of Sciences currently recommends 200 international units (IU) of vitamin D for children and adults up to age 50 and 400 to 600 IU for adults older than age 50. However, researchers now question whether these levels are adequate for optimal health.

So, how much vitamin D is enough? There's still much debate about what the recommendations should be. But most researchers agree that a daily intake of 800 to 1,000 IU would benefit many people — especially those at increased risk of vitamin D deficiency, including:

Babies who are exclusively breast-fed
Older adults
People with limited sun exposure
People with darker skin
People with fat malabsorption, such as due to celiac disease, Crohn's disease, pancreatic insufficiency, liver disease or cystic fibrosis

Many foods contain vitamin D, including fortified milk, cheese and yogurt. Sunlight is also a major source of vitamin D.

If you don't get the recommended amounts of vitamin D in your regular diet or from sun exposure, ask your doctor whether a vitamin D supplement is appropriate for you.