Because of conflicting reports on Vitamin D and Calcium, the U.S. and Canadian governments asked the Institute of Medicine to assess the current data and come up with a recommendation for intake levels of these vitamins. After reviewing thousands of studies, and obtaining input from scientists and experts, they came up with the following conclusions:
- There is a strong body of evidence that substantiates the importance of Vitamin D and Calcium in promoting bone health.
- The health benefits of Vitamin D, beyond bone health, is mixed and inconclusive. More study is needed.
- There is emerging evidence that taking too much Vitamin D may cause kidney damage.
- Because of a lack of standardization in laboratories doing Vitamin D testing, the number of people with Vitamin D deficiency in the U.S. may have been overestimated. (Many labs are using cut-off points for deficiency that are much higher than the Institute of Medicine suggests is appropriate. They say 20 nanograms per milliliter is the level they found to be needed for bone health. Some labs are using higher levels.)
- They recommend 600 I.U. of Vitamin D for people 50 and younger. 800 I.U. for people 51 and older.
- They recommend you do not exceed 4,000 I.U. of Vitamin D daily. (This excludes short-term high dosage therapy doctors recommend for vitamin d deficiency.)