Vitamin D was discovered in 1922 for its role in the development of rickets, a childhood disease characterized by softened and weakened bones. Since then the importance of this vitamin in preventing bone diseases such as rickets and osteoporosis has been widely studied and well established. But recent researches have revealed more benefits of vitamin D, often in previously unrecognized areas.
Vitamin D and Tuberculosis
Tuberculosis, or TB, is a highly infective disease that kills nearly two million people worldwide each year. Vitamin D plays a role in the host defense against this deadly bacteria disease. A type of immune cells called macrophages possess the ability to activate vitamin D, which is circulating in the blood mostly as an inactive hormone. When stimulated by the TB bacteria, macrophages speed up the activation of vitamin D and use it to instruct the production of an antibacterial protein called cathelicidin, which kills TB. The higher risk of contracting TB in people of African descent may be due to vitamin D deficiency, according to Harvard University.
Vitamin D and Autoimmune Diseases
Autoimmune diseases such as multiple sclerosis, type-1 diabetes and Crohn's disease are more prevalent in people living at higher latitude, where they receive less sunlight. Sun exposure stimulates vitamin D production in your body. According to a review by Dr. Michael Holick at Boston University School of Medicine, women who take vitamin D supplements are less likely to develop multiple sclerosis, osteoarthritis and rheumatoid arthritis. Children who receive vitamin D supplements early in life are less prone to develop type-1 diabetes.
What You Should Do
Dark-skinned and home-bound individuals as well as the elderly are at greater risk for developing vitamin D inadequacy. Also at risk are pregnant women, lactating women and infants. If you are among the high risk groups, consult with your doctor for a blood test of 25-hydroxy vitamin D, the circulating form of this vitamin. A blood level less than 30ng per milliliter of 25-hydroxy vitamin D indicates inadequate vitamin D status.
Sources of Vitamin D
Sun exposure is the most effective means of getting vitamin D for most people. Exposing your face, arms, legs or back to the sunlight for 5 to 30 minutes a day between 10 am to 3 pm for at least twice a week is usually sufficient, according to the Office of Dietary Supplements. However, the production of vitamin D in your body decreases with age and may vary with factors such as weather conditions and air pollution. Dietary intake is often necessary. Very few foods naturally contain vitamin D. Fortified foods such as vitamin D-fortified milk and orange juice, and vitamin D-containing supplements provide alternative sources.
