In 1936, Dr Ferdinand Vowinckel was apparently experimenting on himself to see if vitamin D could cure arthritis. Reportedly, he took 2,100,000 IU/day of D2 for 18 days and died.
Why did he take so much? Apparently, the reason he took so much was that the year before two physicians reported that megadoses of vitamin D “cured” arthritis. Dr. Reed and his colleague Dr Dreyer of the University of Illinois, reported giving as much as 3,000,000 IU/day with the average dose being 300,000 to 500,000 IU/day.
By the early late 1930s and early1940s, such doses were reported to be injuring patients.
Deaths were reported. For example, nine weeks after taking 300,000 IU/day, a New Jersey woman died.
However, it took a few years more until such doses were clearly known to cause death or severe toxicity. In 1947, medical convention proceedings warned that “even in doses [of vitamin D] of 50,000 to 100,000 IU/day” could cause toxicity or even death “unless carefully administered.” Apparently, at the time, a 50,000 IU tablet was the lowest dose available.
When I hear of people taking 50,000 IU per day I worry. Everyone is different in how they metabolize vitamin D. Some people can tolerate 50,000 IU per day and some people can’t. By the time you realize you are in the latter category, it may be too late. Make sure to follow the Council’s guidelines for adults of 5,000 IU/day, at the most 10,000 IU/day, as 10,000 IU/day is the no observed adverse effects level (NOAEL) of the 2010 Food and Nutrition Board, the amount that has never been shown to cause harm. Do not exceed 10,000 IU/day unless you have a scientific level of understanding of vitamin D metabolism and test often.