When to Supplement With Vitamin D?

Surveys indicate that the usual dietary intake of vitamin D in the United States is low - 50 to 70 IU per day. Presumably, vitamin D stores are enriched in most people by regular exposure to sunlight, at least during certain times of the year. Recommended intake for vitamin D for males and females aged 51 to 70 is 400 IU, or 600 IU per day if over age 70. Vitamin D is not recommended for infants and children unless supervised by a doctor.

Vitamin D Deficiency
The symptoms of vitamin D deficiency include muscle twitching, cramps, and convulsions, as well as aching bones. Conditions that would cause a vitamin D deficiency include severe liver failure. Crohn's disease, and celiac sprue (a malabsorption disorder caused by an intolerance to a protein found in wheat, rye, oats, and barley).

Children who are vitamin D deficient get rickets, which is characterized by short stature, bowlegs, or "knock-knees," and deformities of the skull. In the United States, rickets was virtually eliminated by the 1930s because of the fortification of milk with vitamin D. In Europe, however, foods are not fortified with vitamin D, which is why rickets continues to be a health problem in some European countries. Adults who are vitamin D deficient develop osteomalacia, sometimes called adult rickets. Osteomalacia doesn't cause bone deformities, but it does result ina decrease of the mineral content of the bones, leaving them more prone to fractures. Some people with osteomalacia complain of deep bone pain. Adults over age 50 should consider getting a blood test for vitamin D levels because until a deficiency is quite severe, it's hard to detect. Women should also consider getting a bone mineral density test.