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Information on the latest vitamin D news and research.

Find out more information on deficiency, supplementation, sun exposure, and how vitamin D relates to your health.

Dear Dr Cannell: Vitamin D in the 1930’s

Dear Dr. Cannell:

I learned somewhere that vitamin D was Rxed in the 1950’s at an average dose of 150,000 units per day to treat asthma and allergies. i don’t know but suspect they would have used D2 as they wouldn’t have known any better. Doses crept up until some were at 1,000,000 units per day before people became symptomatic.

Then I read your last edition of your e-letter and you seemed to warn people against doses that would raise people above 100.

if you know, would you please comment on the doses our predecessors used and at what level people become symptomatic; and why you would recommend that people stay within the reference range (other than medico legal).

You have taught me so much. I very much appreciate your efforts.


James Clark, MD

Dear Dr. Clark:

Beginning in the early 1930s, several doctors began recommending vitamin D (D2) in pharmacological doses for arthritis and asthma. The doses ranged from 100,000 IU/day to 500,000 IU/day and the doctors reported good results. The practice caught on in some medical circles. If the patients developed clinical signs of toxicity, they would stop the vitamin D for several weeks and then restart at a “lower” dose. Sometimes they measured serum calcium but the high results were ignored, depending instead on clinical signs of toxicity in the patient (nausea, anorexia, abdominal pain) to lower the dose.

However, by 1935, deaths from these doses began to be reported in the medical literature, the reports increased in the late 30s, and early 40s until high dose vitamin D treatment was universally condemned.

Unfortunately, in this country, that is how vitamin D got its reputation for easy toxicity. I hope people do not use these doses least history repeat itself.

John Cannell, MD

  About: John Cannell, MD

Dr. John Cannell is founder of the Vitamin D Council. He has written many peer-reviewed papers on vitamin D and speaks frequently across the United States on the subject. Dr. Cannell holds an M.D. and has served the medical field as a general practitioner, emergency physician, and psychiatrist.