The safety of the vitamins: an overview.

On the basis of the reviewed information it is considered that the vitamins can be divided into two broad categories. a) Those with a safety level at least 50-100 times the RDA and no clear indication of serious adverse reactions above the level. This level should be adequate to match any required pharmacological dose, and these vitamins should be regarded as safe for elevated dose use, not necessarily controlled by doctors. b) Those with a safety ratio of about 10 times, often influenced by the health status of the individual or those with serious irreversible adverse reactions. These vitamins (retinol, calciferol, pyridoxine) can be used safely at an RDA level but should only be administered at higher dosage under medical supervision to avoid dose escalation.