Understanding Vitamin D Deficiency
Vitamin D deficiency is a widespread problem today. It is estimated that more than 1 billion people worldwide have low levels of this vital nutrient in their blood and more than 40 percent of U.S. adults are affected by this vitamin deficiency. Not getting enough vitamin D has the potential to affect your health in many ways, so if you think you may be among the many people who are deficient, getting a vitamin D blood test to find out what your blood level is would be wise.
About Vitamin D
Vitamin D is commonly called the sunshine vitamin, and with good reason. Our skin manufactures vitamin D when it is exposed to the sun. While that natural production of vitamin D is where we get the majority of our supply of this nutrient, we also get a relatively small amount from foods, such as fatty fish, eggs and fortified dairy products. Vitamin D is essential to health and well-being in a number of ways. It helps your body maintain healthy bones by regulating the amount of calcium and phosphorus they receive. It helps regulate calcium levels in the blood as well, which aids in maintaining healthy cardiovascular function. Vitamin D also supports healthy muscle, lung, brain and immune system function, and since it is converted into a hormone by the body, it aids communication between cells throughout the body.
Measures the amount of vitamin D, an important factor in bone strength
Vitamin D Deficiency: The Potential Health Effects
The best-known side-effects of vitamin D deficiency are related to bone health. In children, severe vitamin D deficiencies can cause a condition called rickets, while adults may develop a condition called osteomalacia. In both conditions, bones become soft, thin and brittle. It has also been linked to increased risk of osteoporosis, a common disease, often disabling, that makes bones brittle and fragile over time.
According to the Vitamin D council, deficient levels of Vitamin D have also been linked to other conditions, including:
- Many types of cancer
- Type 2 diabetes
- High blood pressure
- Alzheimer's disease
- Autoimmune diseases, including multiple sclerosis, type 1 diabetes and Crohn's disease
According to the Mayo Clinic, there is evidence linking low vitamin D levels to these health issues:
- Thyroid conditions
- Heart disease
- Tooth decay
- Digestive disorders
Symptoms of Vitamin D Deficiency
People with vitamin D deficiencies may have symptoms related to their condition, although many notice no symptoms at all. For those that do experience symptoms, they may include:
- Muscle weakness
- Bone and/or back pain
- Frequent illnesses/infections
- Slow healing
Who is at Risk?
People who are at greater than average risk for vitamin D deficiency include:
- People of color – People with darker skin need more sun exposure to make vitamin D than do those with fair skin, increasing their risk of deficiency.
- People who get little sun exposure – People who spend most of their time indoors, keep most of their skin covered, or wear sunscreen every day are at increased risk.
- People who live in areas with limited overhead sunshine – The further north you are from the equator, the more likely you are to be vitamin D deficient.
- Older people – Skin thins as we age, and thinner skin is often less efficient at manufacturing Vitamin D.
- Breastfeeding babies – If mom is not taking supplements, breastfed babies may not get enough vitamin D.
- Pregnant women – The body uses more vitamin D during pregnancy, which can deplete its stores of the nutrient, leading to deficiency.
- People with a body mass index of 30 or greater – Since body fat absorbs vitamin D from the bloodstream, reducing the supply available for use in the body, high levels of body fat can result in very low levels of vitamin D.
- People with digestive disorders – Disorders like Crohn's disease, celiac disease and irritable bowel syndrome can reduce the absorption of vitamin D from foods or supplements.
- People with kidney disease – To be used by the body, vitamin D must be converted to its active form by the kidneys, making kidney disease a risk factor for deficiency.
- Vegans – Since most foods rich in vitamin D are animal products, a vegan diet can significantly reduce dietary intake of this nutrient.
Vitamin D Testing
Vitamin D levels are checked with blood tests. The most commonly used lab test for this purpose is called a vitamin D 25-hydroxy test. Vitamin D is converted into vitamin D 25-hydroxy as it is processed by the liver. This test measures the concentration of this form of vitamin D in the blood, which is widely considered the best indication of overall vitamin D levels in the body.
Getting tested means having a blood sample drawn and analyzed by a health testing lab. Results are presented as a number in units of ng/ml, which means nanograms per milliliter. The Vitamin D council suggest interpreting vitamin D 25-hydroxy test results as follows:
- D 25-hydroxy levels between 0 and 30 ng/ml indicate deficiency
- D 25-hydroxy levels between 30 and 39 ng/ml are insufficient
- D 25-hydroxy levels between 40 and 80 are sufficient
- D 25-hydroxy levels over 150 ng/ml are toxic
Treatment of vitamin D deficiency focuses on establishing healthy vitamin D levels in the body. Recommendations for improving vitamin D status generally include taking vitamin D supplements, adding foods rich in vitamin D to the diet, and getting at least 15 to 20 minutes of unprotected sun exposure daily.
Vitamin D Council: