Vitamin D, also called the sunshine vitamin, is an essential nutrient. Unfortunately, not everyone gets enough and this can contribute to some illnesses. So we have put together a short Q&A about vitamin D and what it does.

What is vitamin D?

Vitamin D is a nutrient found in fish oils, dairy products, egg yolks and a few other foods. Your skin makes vitamin D when exposed to sunshine.

Why do I need it?

Vitamin D helps the body absorb calcium so it can build strong bones. But research shows that there may be more to this tiny, but mighty vitamin.

One study found that vitamin D may prevent a type of vertigo called benign paroxysmal positional vertigo, or BPPV. Having normal vitamin D levels might protect against some cancers, reports another study. A study published in The American Journal of Clinical Nutrition found that elderly patients with normal levels of vitamin D were better able to walk after a hip fracture. Vitamin D may even prevent infection from COVID-19, reports this study, published in the Journal of the American Medical Association.

How much vitamin D do I need?

The amount of vitamin D you may need varies by age. The recommended daily amount (RDA) for adults aged 19 to 70 years is 600 IU daily. For adults over age 70, the RDA is 800 IU daily. Generally, the level of vitamin D in the blood should be between 30 nmol/L and 125 nmol/L, but a level of at least 50 nmol/L is considered to be healthy for most people.

The National Institutes of Health reports that almost no one in the US has levels of Vitamin D that are considered too high, but some Americans have levels that are too low. The older a person gets, the more vitamin D is needed to maintain normal levels. Nursing babies may need a vitamin D supplement because breast milk does not supply enough of the nutrient. People who don't absorb nutrients well, like those with celiac or Crohn's disease, or people who are obese or have had gastric bypass surgery, are at risk of low Vitamin D levels and may need to supplement. People who eat a vegan diet may not get enough Vitamin D.

Where can I get vitamin D?

Some foods provide vitamin D, such as fatty fish, egg yolks, cheese, beef liver, mushrooms and milk. Vitamin D is added to some processed foods, such as orange juice and cereals. Exposing your skin to the sun causes your body to make vitamin D, but this doesn't work when you're sitting in a window or if it's cloudy. Too much sun exposure can also raise your risk of skin cancer, so remember to limit your time in the sun and put on protective clothing and sunscreen if you'll be out for more than a few minutes. Tanning beds might seem like a good option, but they can also cause skin cancer and aren't recommended.

The two forms of vitamin D

Vitamin D comes in 2 forms: vitamin D2 and vitamin D3. Vitamin D2 comes from plants and can be found in fortified foods. Vitamin D3 is found in animal products and is produced by the body with sun exposure. If your doctor recommends that you take a supplement, be sure to ask which form your doctor prefers.

What happens if I don't get enough?

Children who don't get enough vitamin D can develop rickets, a condition in which bones don't harden, resulting in bones that are deformed. Adults who don't get enough vitamin D can develop osteomalacia, a softening of the bones, but this condition is reversible if vitamin D levels are raised to normal levels.

What if I get too much vitamin D?

You typically can't get too much vitamin D from food or sun exposure. Taking too much of a vitamin D supplement may cause nausea, vomiting, lack of appetite constipation and weight loss. Vitamin D increases the amount of calcium in your blood and having too much calcium in your body may cause kidney or heart damage. It's important to ask your doctor to measure the amount of vitamin D in your blood to make sure you are getting enough and not too much.

Can I take vitamin D with my other medicines?

Vitamin D may interact with certain medicines. You should always check with your doctor or pharmacist before taking any supplement, including vitamin D.