
Studies suggest that there might be some danger in the current trend of taking high dose vitamin D.
As a licensed experienced nutritionist, I have never recommended more than 2,000 IU of vitamin D and that was only for people who were tested as significantly low. If a person's vitamin D does not increase into the normal ranges with 2,000 IU of vitamin D, it is not because of a lack of vitamin D. It is likely the need for the helper nutrients of magnesium and Vitamin A. When I give those WITH the vitamin D, the person's Vitamin D status normalizes.
Also, too much Vitamin D can contribute to too much calcium in the blood - hypercalcemia. Too much calcium in the muscles can cause muscle dysfunction. Vitamin K2 should be taken with Vitamin D to ensure that calcium is moved correctly in the body. 