Vitamin D: criteria for safety and efficacy


RP Heaney, Creighton University Medical Center, 601 N. 30th Street – Suite 4841, Omaha, NE 68131, USA. E-mail:, Phone: +1-402-280-4029, Fax: +1-402-280-4751.


The functional status indicator for vitamin D, for both safety and efficacy, is serum 25-hydroxyvitamin D concentration. Efficacy for several health endpoints requires levels of 80 nmol/L or higher. Toxicity occurs at levels of 500 nmol/L or higher. The input needed for efficacy, in addition to typical food and cutaneous inputs, will usually be 1000–2000 IU/day of supplemental cholecalciferol. Toxicity is associated only with excessive supplemental intake (usually well above 20,000 IU/day).