Vitamin D Deficiency

Medically Reviewed By William C. Lloyd III, MD, FACS

What is vitamin D deficiency?

Vitamin D deficiency is a common condition in which the body has inadequate stores of vitamin D. This fat-soluble vitamin is produced in the skin as a result of exposure to the sun’s rays, which are the main source of vitamin D. Vitamin D is also available in dietary supplements and in liver, eggs, oily fish, and fortified milk and dairy products.

Vitamin D is essential for many aspects of health, including the absorption of calcium and phosphorus from food and the building of strong bones. Vitamin D is also important for hormone regulation, inflammation reduction, and the optimal functioning of the nervous system and the immune system. It is critical for normal development and growth of cells, bones and teeth.

Vitamin D deficiency is far more common than once believed. The sun’s rays are the primary source of vitamin D, and lifestyle changes have made it difficult for many people to get enough time in the sun. Reasons for limited sun exposure include working indoors, as well as using sunscreen and avoiding the sun to prevent skin cancer. People who live in Northern latitudes also have difficulty getting enough vitamin D because in these areas the sun’s rays are not strong enough during winter months to allow the skin to produce sufficient amounts of vitamin D.

Untreated vitamin D deficiency can lead to serious complications, such as bone fractures and bone deformities. Vitamin D deficiency has also been linked to a variety of serious conditions, such as certain cancers and cardiovascular disease. Seeking regular medical care and following your treatment plan can help reduce the risk of serious complications from vitamin D deficiency.

What are the symptoms of vitamin D deficiency?

Symptoms of vitamin D deficiency can vary depending on the individual and the severity of the deficiency. Many people have no symptoms of vitamin D deficiency until complications, such as rickets (a softening of the bones in children), are present. Symptoms may also be mild or subtle. Symptoms of vitamin D deficiency include:

  • Bone pain

  • Delayed tooth formation

  • Dental deformities

  • Developmental motor delay

  • Easily fractured bones

  • Increased perspiration

  • Muscle cramps

  • Poor growth in children

  • Spine and other bone deformities

  • Stooped posture and a loss of height

  • Tingling

  • Weakness

What causes vitamin D deficiency?

A major cause of vitamin D deficiency is limited sun exposure. Your skin produces vitamin D when it is exposed to the sun. Many people who live far from the equator in the northern and southern hemispheres get inadequate exposure to the sun because the sun’s rays are not strong enough during winter months. Having an indoor occupation and using sunscreen also limit the amount of sun exposure a person receives.

Vitamin D deficiency can be caused by not eating enough food rich in vitamin D, such as liver, eggs, oily fish, and fortified milk and dairy products. People at risk for vitamin D deficiency include vegetarians, vegans and infants, especially breast-fed infants.

Vitamin D deficiency can also be caused by a condition in which the kidneys cannot convert vitamin D into its active form that the body can use. In addition, as people grow older, their kidneys are less able to effectively convert vitamin D into its active form.

Certain diseases of the digestive system can cause malabsorption of vitamin D from food in the intestines. These include Crohn’s disease, celiac disease, and cystic fibrosis. Obesity and gastric bypass surgery can also lower vitamin D stores in the body.

What are the risk factors for vitamin D deficiency?

A number of factors are thought to increase your chances of developing vitamin D deficiency:

  • Age older than 50 years

  • Avoiding sun exposure or working at an indoor occupation

  • Being breast-fed

  • Crohn’s disease

  • Cystic fibrosis

  • Dark skin (Dark skin has high levels of the pigment melanin, which reduces the skin’s ability to produce vitamin D.)

  • Excessive use of sunscreen

  • Gastric bypass surgery

  • Kidney or liver disease

  • Living in Northern latitudes

  • Malabsorption syndrome

  • Obesity

  • Using antacids

  • Vegetarian or vegan diet

How can you reduce your risk for vitamin D deficiency?

In some cases, you can prevent vitamin D deficiency by getting adequate sun exposure. It is also important to eat a diet that includes a sufficient amount of vitamin D. Foods high in vitamin D include fortified milk and dairy products, liver, eggs, and oily fish.

You may also need to take a vitamin D supplement, as recommended by your health care provider, if you:

In addition, breast-fed infants may need vitamin D supplementation.

How is vitamin D deficiency treated?

Vitamin D deficiency is treatable. With prompt diagnosis and treatment, you can expect to have a good prognosis and a minimal risk of developing serious permanent complications, such as rickets, osteomalacia and osteoporosis.

Treatment of vitamin D deficiency includes:

  • Eating more foods rich in vitamin D, such as fortified milk and dairy products, liver, eggs, and oily fish

  • Increasing sun exposure

  • Taking oral vitamin D supplements

  • Treating underlying causes and risk factors for vitamin D deficiency

Receiving regular medical care, monitoring the condition, and treating any underlying diseases or disorders, such as Crohn’s disease, cystic fibrosis, and liver disease, are also necessary to ensure a good prognosis.

What are the potential complications of vitamin D deficiency?

Complications of vitamin D deficiency can be serious. You can treat vitamin D deficiency and minimize the risk of complications by following the treatment plan that you and your health care professional design specifically for you.

Serious complications of vitamin D deficiency include:

  • Bone deformities

  • Bone fractures

  • Growth abnormalities

  • Osteomalacia (soft, weak bones due to lack of vitamin D during the bone-building process)

  • Osteoporosis (loss of calcium from previously formed bones)

  • Rickets (osteomalacia in children)

Vitamin D deficiency has also been linked to:

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  1. Domino FJ (Ed.) Five Minute Clinical Consult. Philadelphia: Lippincott Williams & Wilkins, 2013.
  2. Misra M, Pacaud D, Petryk A, et al. Vitamin D deficiency in children and its management: review of current knowledge and recommendations. Pediatrics 2008; 122:398.
Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jan 20
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