Symptoms of vitamin D deficiency can occur when the level of vitamin D in the body drops below the range of 30 to 74 nanograms per milliliter, according to MedlinePlus. The side effects are normally subtle, according to WebMD, but when present, they include muscle weakness and bone pain.Continue Reading
Even in the absence of symptoms, vitamin D deficiency poses risks to health. Low levels of vitamin D have been associated with cognitive impairment in older people, severe asthma in children, cancer and increased risk of death due to cardiovascular disease, according to WebMD. Vitamin D is thought to be important for the prevention and treatment of several conditions, including both Type 1 and Type 2 diabetes, glucose intolerance, hypertension and multiple sclerosis.
The test to check blood levels of vitamin D is known as the 25-hydroxy vitamin D test, as explained by MedlinePlus. This test measures the active form of vitamin D via a blood sample.
Abnormal results can indicate a lack of sufficient vitamin D in the diet and lack of exposure to natural sunlight, according to MedlinePlus. Abnormal levels can also indicate liver or kidney disease, malabsorption of food, and the use of medicines such as rifampin, phenobarbital and phenytoin. It is not uncommon for low levels of vitamin D to be seen in children of African American descent, particularly during winter and in breastfed infants.Learn more about Nutritional Amounts & Limits