What Is Vitamin D Deficiency?
A vitamin D deficiency means you don’t have enough of this vitamin in your body. You need vitamin D to grow and maintain your bones. You could be at risk for deficiency if you don’t get enough sunlight on your skin, you have a disorder that reduces your body’s ability to absorb it, or you don’t eat enough of it in your diet.
Also known as the sunshine vitamin, your body can make it when your skin is exposed to sunlight. But it’s also found in a few foods, such as some fish, fish liver oils, and egg yolks, as well as in fortified dairy products and orange juice.
Why Is Vitamin D Important?
You need vitamin D to build bones and keep them strong. Vitamin D works to build bones by helping your body absorb and use calcium, magnesium, and phosphate from the food you eat. It balances out the level of calcium in your bones and blood. When you don’t take enough vitamin D, your calcium levels drop. Your body has to pull calcium from your bones into your blood to bring your levels back into balance. Vitamin D also plays a role in how your nervous system, immune system, and muscles work.
Vitamin D deficiency can cause weak bones — a condition called osteoporosis in adults and rickets in children. Low blood levels of this vitamin have also been linked to an increased risk for:
Type 2 diabetes
Cancer
Heart disease and stroke
Depression
Multiple sclerosis
Vitamin D Levels
To determine your vitamin D status, your doctor will measure the concentration of 25-hydroxyvitamin D in your blood.
It’s challenging to come up with a minimum amount of vitamin D in the blood that will work for most people. Experts agree that it probably varies based on your age, race or ethnicity, and the type of test your doctor orders. However, according to an expert committee of the Food and Nutrition Board (FNB) at the National Academies of Sciences, Engineering, and Medicine (NASEM):
- 50 nanograms per milliliter or more is probably too high and may cause health problems
- 20 nanograms per milliliter or more is probably good enough for most healthy people to maintain overall health
- 12 nanograms per milliliter or less is considered deficient
Vitamin D deficiency may be categorized in the following way:
Severe deficiency: Less than 5 nanograms per milliliter
Mild deficiency: Less than 20 nanograms per milliliter
Moderate deficiency: Less than 10 nanograms per milliliter