What is vitamin D deficiency?

Vitamin D deficiency means that you do not have enough vitamin D in your body. Vitamin D is unique because your skin actually produces it by using sunlight. Fair-skinned individuals and those who are younger convert sunshine into vitamin D far better than those who are darker-skinned and over age 50.

Why is vitamin D so important?

Vitamin D is one of many vitamins our bodies need to stay healthy. This vitamin has many functions, including:

  • Keeping bones strong: Having healthy bones protects you from various conditions, including rickets. Rickets is a disorder that causes children to have bones that are weak and soft. It is caused by a lack of vitamin D in the body. You need vitamin D so that calcium and phosphorus can be used to build bones. In adults, having soft bones is a condition called osteomalacia.
  • Absorbing calcium: Vitamin D, along with calcium, helps build bones and keep bones strong and healthy. Weak bones can lead to osteoporosis, the loss of bone density, which can lead to fractures. Vitamin D, once either taken orally or from sunshine exposure is then converted to an active form of the vitamin. It is that active form that promotes optimal absorption of calcium from your diet.


What are the Health Effects of Getting Enough Vitamin D?

Getting enough vitamin D may also play a role in helping to keep you healthy by protecting against some conditions such as fractures from poor bone health.

How much Vitamin D do you need?

In healthy people, the amount of vitamin D needed per day varies by age. If your doctor is checking your blood levels, he or she might recommend higher or lower dose than the Recommended Dietary Allowance based on your individual needs.

If you have osteoporosis, your doctor might suggest a blood test of your vitamin D levels. The amount of vitamin D supplement can be customized for each person, based on the results. For many older patients, a vitamin D supplement containing anywhere between 800 to 2000 IUs daily, which can be obtained without a prescription, can be both safe and beneficial. It is important to speak with your doctor about your individual needs.


What does sunlight have to do with getting enough Vitamin D?

Vitamin D is produced when your skin is exposed to sunshine, or rather, the ultraviolet B (UV-B) radiation that the sun emits. The amount of vitamin D that your skin makes depends on such factors as the season, where you live, the time of day, the amount of cloud cover and the melanin content of your skin.

What does your diet have to do with getting enough vitamin D?

Vitamin D doesn’t occur naturally in many foods. That’s why certain foods have added vitamin D. In fact, newer food nutrition labels show the amount of vitamin D contained in a particular food item.

It may be difficult, especially for vegans or people who are lactose-intolerant, to get enough vitamin D from their diets, which is why some people may choose to take supplements. It is always important to eat a variety of healthy foods from all food groups. The vitamin content of various foods is shown in the following table.

It is important to check product labels, as the amount of added vitamin D varies when it is artificially added to products such as orange juice, yogurt and margarine.


What are the sources of Vitamin D?

You can get vitamin D in a variety of ways. These can include:

  • Being exposed to the sun. About 15-20 minutes three days per week is usually sufficient.
  • Through the foods you eat.
  • Through nutritional supplements.

What other factors can lead to vitamin D deficiency?

  • Age: The skin’s ability to make vitamin D lessens with age.
  • Mobility: People who are homebound or are rarely outside (for example, people in nursing homes and other facilities) are not able to use sun exposure as a source of vitamin D.
  • Skin color: Dark-colored skin is less able to make vitamin D than fair-colored skin.
  • Human breast milk: A woman’s breast milk only contains a small amount of vitamin D. Often infant formulas also only include a small amount of D also. Therefore infants are at risk of not receiving enough vitamin D. 

Can medications cause a vitamin D deficiency?

Yes. Vitamin D levels can be lowered by certain medications. These include Laxatives, Steroids (such as prednisone) and Cholesterol-lowering drugs. Please check with your Doctor or Pharmacist regarding this question.

Always tell your doctor and pharmacist about the drugs you take and any vitamin D supplements or other supplements or herbs/alternative health products that you take.

What are the signs and symptoms of vitamin D deficiency?

Severe lack of vitamin D causes rickets, which shows up in children as incorrect growth patterns, weakness in muscles, pain in bones and deformities in joints. This is very rare. However, children who are deficient in vitamin D can also have muscle weakness or sore and painful muscles.

Lack of vitamin D is not quite as obvious in adults. Signs and symptoms might include Fatigue, Bone pain, Muscle weakness, muscle aches, or muscle cramps and Mood changes, like depression.



Fitzgerald PA. Fitzgerald P.A. Fitzgerald, Paul A.Endocrine Disorders. In: Papadakis MA, McPhee SJ, Rabow MW. Papadakis M.A., McPhee S.J., Rabow M.W. Eds. Maxine A. Papadakis, et al.eds. Current Medical Diagnosis & Treatment 2019 New York, NY: McGraw-Hill; .

  • Bender DA. Bender D.A. Bender, David A.Micronutrients: Vitamins & Minerals. In: Rodwell VW, Bender DA, Botham KM, Kennelly PJ, Weil P. Rodwell V.W., Bender D.A., Botham K.M., Kennelly P.J., Weil P Eds. Victor W. Rodwell, et al.eds. Harper’s Illustrated Biochemistry, 31e New York, NY: McGraw-Hill.
  • National Institutes of Health Office of Dietary Supplements. Vitamin D. Accessed 10/16/19.
  • Genetic and Rare Disease Information Center. Rickets. Accessed 10/16/2019.
  • Vitamin D Council. Vitamin D hypersensitivity. Accessed 10/16/2019.