Too much Vitamin D is extremely rare, but it can happen and should be avoided. Learn about high levels of
Vitamin D here.
Vitamin D can be harmful if taken in excess. Vitamin D intoxication is extremely rare but can be caused by accidental or intentional intake of high doses of vitamin D. The amount of vitamin D that causes vitamin D toxicity is more than 4 times the amount that adults get naturally through exposure to sunshine. Most reports of vitamin D toxicity have been as a result of mistakes in vitamin D manufacturing facilities, or errors in medically dosing with prescription vitamin D.
Symptoms and consequences of Vitamin D toxicity:
How much is too much?
The following summarize the facts for adults:
The current safety limit for vitamin D supplements in adults is 2,000 IU (50ug)
Review of the literature shows the lowest dose of vitamin D proven to cause toxicity in adults is 40,000 IU/day for many months
Farmers and lifeguards, who are exposed to long periods of sunlight would manufacture 10,000 IU of vitamin D in their skin daily without the use of sunscreen.³
Some experts believe that the official safety limit is very conservative and not based on current evidence
The following summarizes the facts for infants:
“The Tolerable Upper Intake Level (UL) for vitamin D for infants up to one year of age is set at 25ug (1,000 IU) per day which is based on studies examining the highest intake at which no adverse affects were observed on linear growth.” Note that the UL is defined as the highest continuing daily intake of a nutrient that is likely to pose no health risks for almost all individuals.
Overall, it is best to seek individual advice from an informed healthcare profession who is familiar with vitamin D and your health status. Also, follow the directions on the label of products and notify your healthcare provider if you have concerns.
1Cannell J., Hollis BW, Zasloff M, Heaney RP. Diagnosis and treatment of vitamin D deficiency. Expert Opin Pharmacother. 2008; 9(1);1-12.
2Standing Committee on the Scientific Evaluation of Dietary Reference Intakes: Dietary reference intakes: calcium, phosphorus, magnesium, vitamin D and fluoride. National Academy Press, 1997.
3Vieth R. Vitamin D supplementation, 25-hydroxyvitamin D concentrations and safety. Am J Clin Nutr. 1999; 69; 842-856
4Hathcock JN, Shao A, Veith R, Heaney R. Risk assessment for vitamin D. Am J Clin Nutr. 2007; 85; 6-18 5Vitamin D supplementation for breastfed infants 2004. Health Canada recommendation document (p3)