Vitamin D is known as the sunshine vitamin. Vitamin D helps the body absorb calcium and is needed for optimal skeletal health. The term vitamin D refers to either vitamin D2 or Vitamin D3. Vitamin D3, also know as cholecalciferol, is either produced endogenously when ultraviolet rays from sunlight strike the skin and trigger vitamin D synthesis or it is obtained in the diet from fatty fish. Vitamin D2, also known as ergocalciferol, is obtained from irradiated fungi, such as yeast.
Symptoms of bone pain and muscle weakness can mean that you may have a vitamin D deficiency. The symptoms may also be subtle. Low blood levels of this vitamin may cause cognitive impairment in older adults, increased risk of death from cardiovascular disease and cancer.
Vitamin D deficiency can result from a variety of causes, including inadequate exposure to sunlight, malabsorption problems and effects of certain medications. Medications like prednisone, often prescribed to reduce inflammation, can reduce calcium absorption and impair vitamin D metabolism. Both the weight loss drug, orlistat, and cholesterol lowering drug, cholestyramine, can reduce the absorption of vitamin D and other fat soluble vitamins. Other risk factors include obesity (body mass index greater than 30). It is also associated with older age (50+) and digestive disorders like celiac disease.
In the United States, vitamin D deficiency is highest among people who are elderly, institutionalized or hospitalized. Sixty percent of nursing home residents and 57 percent of hospitalized patients were found to be vitamin D deficient.
However, vitamin D deficiency is not restricted to the elderly and hospitalized population: several studies have found a high prevalence to Vitamin D deficiency among young healthy adults.
Vitamin D supplementation offers protection against fractures, has been shown to improve bone mineral density, and may decrease the risk of developing breast, colon and prostate cancer. It is also associated with a reduction of falls in the older population. Research suggests that vitamin D could play a role in prevention and treatment of a number of conditions, including type 1 and type 2 diabetes, hypertension, glucose intolerance and multiple sclerosis.
The blood serum concentration of 25-hydroxy-vitamin D is typically used to determine vitamin D status. It reflects vitamin D produced in the skin as well as threats from the diet but does not reveal the amount of vitamin stored in other body tissues. Individuals who are at high risk for vitamin D deficiency, including patients with osteoporosis, malabsorption syndromes, black and Hispanic individuals, obese individuals and those with other medical conditions should be screened. The daily maintenance dose of vitamin D varies by age but most children and adults require 400 to 2,000 IU of vitamin D daily.
Carolyn Reeves, DO at the Northwest Primary Care in Bentonville, Ark.
