A Guide to Vitamin D: Benefits, Sources, Risks, and More

Medically Reviewed By Peter Pace, MS, RDN, CSCS, CPT
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Vitamin D helps your body make full use of calcium. If you do not get enough calcium, you may experience bone problems, such as rickets or osteoporosis. Vitamin D also plays an important part in your nerve, muscle, and immune function. You can get vitamin D through diet and supplements. Fatty fish and fish oils are some of the best sources of vitamin D. This includes salmon, tuna, trout, and mackerel.

You can also get vitamin D from your skin absorbing sunlight. Too much exposure to sunlight can bring health risks such as skin cancer, so it is good to get vitamin D from dietary sources too.

This article explains the benefits of vitamin D, provides ideas of foods you can get vitamin D from, and explores the risks of vitamin D deficiency.

The health benefits of vitamin D

there is a cooked fish on a yellow plate
Carmen Palma/Stocksy United

Adequate vitamin D levels can bring many health benefits to your body, the most notable of which is improving your body’s ability to absorb calcium.

Calcium absorption

One of the most important roles that vitamin D can play in the body involves calcium. Calcium is crucial for bone health, and having appropriate vitamin D levels can help you make full use of its benefits.

Vitamin D promotes the absorption of calcium in your gut. It also helps your body maintain the right levels of serum calcium and phosphate concentrations it needs for bone mineralization. This can help prevent hypocalcemic tetany, which occurs when the muscles cramp and spasm.

Because of its effects on calcium absorption, vitamin D can help prevent:

  • brittle, thin, or misshapen bones
  • osteoporosis
  • rickets
  • osteomalacia

Other benefits

Having adequate levels of vitamin D has many other benefits for your health, including:

  • reducing inflammation
  • modulating cell growth
  • boosting neuromuscular and immune function
  • improving glucose metabolism

Dietary sources of vitamin D

There are many foods that are great sources of vitamin D. If you can, incorporate these foods into your diet to get the benefits of vitamin D without the dangers of sun exposure.

FoodAmountPercentage of the daily value of vitamin D
cod liver oil1 tablespoon170%
cooked trout3 ounces (oz)81

%

cooked salmon3 oz71

%

UV-treated white mushroomshalf a cup46

%

canned sardines2 sardines6

%

scrambled egg1 large egg6

%

braised beef liver3 oz5

%

canned tuna3 oz5

%

Fortified foods

Most foods that contain high levels of vitamin D are animal products. However, there are fortified foods that people can choose as an alternative.

Fortified foodAmountPercentage of the daily value of vitamin D
soy, almond, and oat milks1 cup13–18%
ready-to-eat cereal1 serving10%

Supplements

Vitamin D is also available in supplement form. Some people may choose to take vitamin D supplements if they are more likely to have a deficiency. Such people include:

  • older adults
  • infants who are receiving breast milk
  • people with dark skin
  • people with obesity
  • those with certain health conditions, such as:

You should always discuss supplements and correct dosages with your doctor.

Vitamin D from the sun

Vitamin D is well known for being a benefit of sun exposure. Our skin converts UV rays into vitamin D if it is unprotected.

However, it is important to remember that sun exposure can increase the risk of skin cancer. Therefore, it may be safer to receive vitamin D through a combination of responsible sun exposure and dietary sources and supplements.

The following table shows the recommended daily amounts of vitamin D in micrograms (mcg).

AgeAmount
0–12 months10 mcg
1–70 years15 mcg
over 70 years20 mcg

Breast milk

If you are pregnant or lactating, you need 15 mcg of vitamin D per day.

According to the Centers for Disease Control and Prevention (CDC):

  • Infants who are receiving only breast milk will need vitamin D supplementation, as breast milk does not contain all the vitamin D they need.
  • Infants who are receiving formula will not need vitamin D supplementation.
  • Infants who are receiving a combination of formula and breast milk will still need vitamin D supplementation.

Discuss this with your doctor.

Signs and symptoms of vitamin D deficiency

In children, vitamin D deficiency can appear as rickets. Signs and symptoms of this include:

In adults, vitamin D deficiency can cause osteomalacia. Signs and symptoms of osteomalacia include:

  • bone pain
  • bone irregularities
  • seizures
  • spasms
  • tooth anomalies

Risks of too much vitamin D

Getting too much vitamin D can lead to a condition called hypercalcemia, which occurs when there is too much calcium in the body. People with this condition may experience:

Experts believe that excessive vitamin D is more likely to come from supplementation than from sun exposure.

It is also important to remember that most people in the United States have low levels of vitamin D rather than overly high levels. This highlights the importance of discussing all supplementation dosages with a doctor or registered dietitian.

Medication interactions

Vitamin D supplements may have negative effects in people who take certain medications.

If you take any of the following medications, discuss vitamin D supplementation with your doctor before beginning:

  • orlistat
  • statins
  • steroids
  • thiazide diuretics

Summary

Vitamin D plays a vital role in the body’s absorption of calcium. Because of this, it can strengthen bones and muscles.

Most people in the U.S. do not have sufficient vitamin D levels and are at risk of certain conditions, such as osteomalacia and rickets.

The body does convert sunlight into vitamin D, but there are many risks associated with sun exposure, including skin cancer. Therefore, it may be safer to get adequate vitamin D levels through a combination of responsible sun exposure and dietary sources and supplements. There are also several vitamin D-fortified foods that are not animal-based.

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Medical Reviewer: Peter Pace, MS, RDN, CSCS, CPT
Last Review Date: 2022 Mar 29
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