Evidence

Research on vitamin D use for specific conditions shows:

• Cancer. Findings on the benefits of vitamin D for cancer prevention are mixed. More studies are needed to determine whether vitamin D supplementation may reduce the risk of certain cancers.
• Cognitive health. Research shows that low levels of vitamin D in the blood are associated with cognitive decline. However, more studies are needed to determine the benefits of vitamin D supplementation for cognitive health.
• Inherited bone disorders. Vitamin D supplements can be used to help treat inherited disorders resulting from an inability to absorb or process vitamin D, such as familial hypophosphatemia.
• Multiple sclerosis. Research suggests that long-term vitamin D supplementation reduces the risk of multiple sclerosis.
• Osteomalacia. Vitamin D supplements are used to treat adults with severe vitamin D deficiency, resulting in loss of bone mineral content, bone pain, muscle weakness and soft bones (osteomalacia).
• Osteoporosis. Studies suggest that people who get enough vitamin D and calcium in their diets can slow bone mineral loss, help prevent osteoporosis and reduce bone fractures. Ask your doctor if you need a calcium and vitamin D supplement to prevent or treat osteoporosis.
• Psoriasis. Applying vitamin D or a topical preparation that contains a vitamin D compound called calcipotriene to the skin can treat plaque-type psoriasis in some people.
• Rickets. This rare condition develops in children with vitamin D deficiency. Supplementing with vitamin D can prevent and treat the problem.