Vitamin D prevents the breakdown and deterioration of bones in the body. Regular exposure to natural sunlight is the primary mode of absorption to ensure adquate levels. Vitamin D synthesis is dependent on UV sun exposure. Very few foods contain Vitamin D, and Vitamin D obtained through ingestion (by food or supplementation) is biologically inactive. As more routine screening has identified increasing deficiencies (low blood calcidiol of 25-hydroxy-vitamin D) in the overall population (especially amongst the elderly) oral supplementation of Vitamin D has increased substantially in recent years. Some studies have shown that Vitamin D supplements are effective for improving bone health, strengthening the immune system, reducing fatigue, and improving mood. However, more recent research has found no health benefits to oral Vitamin D supplementation, and some studies found greater risks of toxicity associated with oral supplements. A secondary review of the existing literature was conducted to determine the safety and efficacy of oral Vitamin D supplementation.
