Vit D Toxicity Redefined: Vit K and the Molecular Mechanism
With the mounting evidence of very high rates of Vit D deficiency and the gradually increasing use of Vit D in higher levels, any increased understanding into how toxicity would occur is valuable.
This author suggests that the toxicity of Vit D may be related to interfering w/ Vit K metabolism. If this is proves true, the addition of Vit A may help alleviate side effects associated with even higher dosages. Keep in mind that toxicity from Vit D is not seen with commonly used levels (1,000 to 4,000 IU / day).