What is vitamin D deficiency?

Vitamin D deficiency is common around the world. Though Vitamin D is called a vitamin, it is actually a prohormone. A prohormone is something that your body converts into a hormone.
You use vitamin D in your body to help absorb calcium. It’s linked to many other health conditions.
Vitamin D deficiency occurs when your body doesn’t have or make enough vitamin D.
Vitamin D helps your body absorb calcium and keep a balanced amount of it in the blood. This helps your body strengthen your bones. Vitamin D also has many other functions.
The body makes vitamin D from sunlight. When sunshine hits your skin, a chemical reaction occurs. Your liver and kidneys convert vitamin D to an active form that your body can use.
Sometimes you may not have enough and this is called vitamin D deficiency.
Symptoms of vitamin D deficiency
Vitamin D deficiency causes a number of problems.
In order to work in your body, vitamin D must bind to a protein called a receptor. Every cell in your body has receptors for vitamin D. It plays a role in your muscle, immune, and nervous systems.
Symptoms of vitamin D deficiency include:
Causes of vitamin D deficiency
Vitamin D deficiency is common around the world. It can be caused by several factors.
Not enough sunlight
Not enough exposure to sunlight is the most common cause of vitamin D deficiency. This occurs in people who do not spend much time outside. It is also common among older or sick people who live in a nursing home, are hospitalized or housebound.
Vitamin D deficiency is also common with people who live in far northern or far southern parts of the world. This is because there is less exposure to sunlight during longer winter seasons.
This type of Vitamin D deficiency can also occur in people who keep their bodies fully covered most of the time.
Breastfed babies who are not exposed to sunlight may also be at risk for vitamin D deficiency. Breast milk does not contain enough vitamin D for their development.
Not enough in your diet
Vitamin D deficiency can also occur because you don’t get enough from your diet.
Some countries don’t fortify their milk products with vitamin D. People who are lactose intolerant or who don’t consume dairy products or vitamin-rich foods also may not get enough.
Kidney or liver disease
Some people may not have enough vitamin D because their liver or kidneys cannot convert vitamin D to its active form. This can cause deficiency.
Malabsorption disorder
Vitamin D is a fat-soluble vitamin, which means it is stored in your fatty tissue and liver.
If you have a malabsorption disorder or you are unable to absorb fats, you may not be able to absorb enough vitamin D from food.
Medications
Some medications may interfere with your body’s ability to absorb or convert vitamin D.
These may include anticonvulsants, glucocorticoids, antifungal drugs, medicines for autoimmune disorders, and the antibiotic rifampin.
Sunscreen
Even if you get enough sunlight, there may be times when your skin forms less vitamin D. This may occur in older people, people who have darker skin, and people who wear sunscreen.
Certain other conditions or diseases may also cause vitamin D deficiency. These include:

QUESTION
Next to red peppers, you can get the most vitamin C from ________________. See AnswerTests for vitamin D deficiency
Your doctor will take a list of your symptoms and your personal and medical history to diagnose your vitamin D deficiency. They may ask about your diet and sun exposure.
The most common test for vitamin D deficiency is a blood test. Your doctor will measure the levels of vitamin D, calcium, and phosphate in your blood.
In some far northern and southern areas of the world, doctors may not test your blood. They may simply recommend you eat vitamin-rich foods or take a supplement, as vitamin D deficiency is a common problem.
If you or your child are experiencing muscle spasms or bone pain, your doctor may do imaging tests like an X-Ray to check the structure and health of your bones.
Treatments for vitamin D deficiency
Treatment for vitamin D deficiency usually involves taking high doses of vitamin D for one month to bring your levels up. After one month, your doctor may reduce your intake to the normal daily recommended dose.
Your doctor will recommend:
- Vitamin D supplement
- Sometimes calcium and phosphate supplements
You can usually buy vitamin D supplements as over-the-counter products at your pharmacy. People with liver or kidney disease may need specific kinds of vitamin D supplements.
You can eat a diet rich in vitamin D to prevent vitamin deficiency. These foods include:
- Cheese
- Mushrooms
- Egg yolks
- Beef liver
- Fatty fish like salmon, tuna, and mackerel
You can also get vitamin D from fortified foods. Some countries fortify milk and plant milks, but not all do. You should check the label.
Vitamin D fortified foods may include:
- Milk
- Orange juice
- Yogurt
- Cereal
- Soy milk
- Other plant milks
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Health Solutions From Our Sponsors
Merck Manual: "Vitamin D Deficiency."
Wirral University Teaching Hospital: "Treatment of Vitamin D Deficiency in Adults."
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