I assume these are both result from the fact that "The U.S. Dietary Reference Intake Tolerable Upper Intake Level (upper limit) of vitamin D for children and ad

I assume these are both result from the fact that "The U.S. Dietary Reference Intake Tolerable Upper Intake Level (upper limit) of vitamin D for children and adults is set at 50 micrograms/day (2,000 IU)," the U.S. Dietary Reference being a product of the USDA. There's a long history of government medical pronouncements being mistaken or outdated (e.g. encouraging grains over fat consumption), perhaps due to the incentives under which regulatory bodies operate - there's little disincentive for being suboptimal or even mistaken, as in the case of fat. The incidences I've found of Vitamin D toxicity have been found at far higher levels, 40-50,000 IU. For reference a toxic aspirin dose is roughly 30x a standard dose. Source: http://en.wikipedia.org/wiki/Vitamin_D#Overdose_by_ingestion http://en.wikipedia.org/wiki/Vitamin_D#Overdose_by_ingestion