Hypovitaminosis D

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at February 29, 2016
StartDiseasesHypovitaminosis D

Hypovitaminosis D, commonly referred to as a vitamin D deficiency, is a prevalent condition affecting approximately 8% of people in the United States. It results from an inadequate nutritional intake of vitamin D, inadequate sunlight exposure to ultraviolet B rays, or lack of both. It can lead to serious adverse health problems because vitamin D is essential for proper body functioning in people of all ages.


Definition & Facts

Vitamin D is a fat-soluble vitamin which is stored in the body's liver and fatty tissues. Vitamin D performs as both a vitamin and a hormone in the body. It is important for the body because it helps to keep bones strong. There are two main sources of vitamin D which are food and sunlight.

Having a vitamin D deficiency means the body has low levels of vitamin D in the blood, and this can cause some serious health risks. Hypovitaminosis D is commonly known for causing rickets in children and osteomalacia in adults. Having low levels of vitamin D is also associated with increased risks for serious diseases such as cancer, cardiovascular disease, osteoarthritis, skeletal diseases, metabolic disorders, infections, and autoimmune disease. However, hypovitaminosis D is treatable.

Symptoms & Complaints

When vitamin D deficiency is only mild to moderate, no symptoms may be prevalent. If the hypovitaminosis is severe, these symptoms may arise:


Vitamin D is produced by the body’s response to the skin being exposed to sunlight, and in particular, ultraviolet B rays. It can also be caused by inadequate intake of vitamin D through a balanced diet. Certain people are at greater risk for developing hypovitaminosis D including:

  • People who are not exposed to direct sunlight because they do not get enough sunlight and UV radiation
  • People of darker skin colors because dark pigmentation reduces vitamin D production in the skin
  • Those who live in the northern latitudes in winter because of the lack of sunny days
  • Those with have milk allergies because they do not get vitamin D from fortified milk products
  • Those who are strictly vegan because their diet is not rich in vitamin D
  • People with liver disease because the liver produces vitamin D and liver conditions impair synthesis
  • Those with kidney disease because their body cannot convert the vitamin D to its active form
  • Obese people because the vitamin D is extracted from the blood by fat cells
  • Adults over the age of 65 because as people age, the body has a harder time absorbing vitamins and minerals

There are also conditions and procedures that affect the body’s ability to absorb vitamin D from the gastrointestinal tract. These conditions include, but are not limited to celiac disease, inflammatory bowel disease, and bariatric surgery.

Diagnosis & Tests

If symptoms of inadequate vitamin D arise contact a doctor. The doctor will ask about symptoms and ask for a thorough medical history. A physical examination will be conducted, and then a blood sample will be drawn for a blood test. The blood test is the most accurate way to measure how much vitamin D is present in the body.

The specific test used is the 25-hydroxy vitamin D blood test. A level of 20 nanograms per milliliter to 50 nanograms per milliliter of vitamin D is considered normal and healthy. Levels lower than 12 nanograms per milliliter indicate a vitamin D deficiency. Once a deficiency is found, there are several options for treatment.

Treatment & Therapy

The goal of treatment is to bring vitamin D levels back to normal, to relieve any associated symptoms, and to decrease the risk of fractures, falls, and other adverse health risks that the patient is prone to. Vitamin D deficiency is treatable, and the treatment is painless. The doctor will recommend one or more of the following treatments:

  • Taking Vitamin D supplements is one option. In the beginning, the patient is given vitamin D3 supplementation in high doses. All vitamin D oral supplements should be taken with a meal that contains fat to help the body absorb the vitamin D. The following weeks, lower doses of vitamin D3 are given. The doses are continued until blood levels return to normal. This entire process takes place over approximately 6-12 weeks.
  • Calcium supplements are often used in conjunction with vitamin D supplements to increase D levels. This can also improve bone strength especially in older women with lower vitamin D levels.
  • Light therapy is another option. The patient is exposed to sunlight or UV radiation which increases D levels. This method works because vitamin D3 is produced in the skin when it is exposed to certain light sources.

Prevention & Prophylaxis

The recommended dietary allowance of vitamin D is 600 international units, or IUs, for people ages 1-70. It is raised to 800 IUs for adults older than age 70 in order to optimize bone health. The safe upper limit is about 4,000 IUs per day.

To make sure that you get the recommended daily amount of vitamin D and prevent hypovitaminosis D, eat a healthy diet. Vitamin D occurs naturally in some foods. Seek out foods that are enriched with vitamin D such as:

  • Fatty fish like salmon, trout, mackerel, tuna, and eel
  • Fish liver oils
  • Beef liver
  • Egg yolks
  • Vegetables like portabella mushrooms and spinach
  • Fortified milk
  • Some juices
  • Fortified grain products - cereals

In addition, you should take a vitamin D supplement if recommended by your doctor. This is okay for children and adults alike. You should also follow your doctor’s advice on getting certain amounts of sun exposure per day or use a UV lamp in your home. Get a doctor’s recommendation on a UV lamp before making a purchase.