People do not worry about vitamin D toxicity today as they did 14 years ago, when I started the Vitamin D Council. Then, anything above 400 IU/day was considered toxic by many people. However, toxicity does occur and frequently linked to a manufacture’s error. That is, instead of a 1,000 IU capsule, they make an order of magnitude error and make a 1,000,000 IU capsule.
The reason for such errors is that not all manufactures know how potent vitamin D is. For example, 1 mg of vitamin D is 40,000 IU. If you are taking 5,000 IU/day, all you are taking is 125 mcg. When you look at your other supplements of prescriptions, you will see virtually all of them are mg dosages. The only exception that comes to mind is thyroid hormone where 125 – 250 mcg are standard doses. (It is interesting that the two hormones have the same ranges, 125 – 250 mcg/day or 5,000 – 10,000 IU)
Not many people know that vitamin D supplementation dosages have dramatically changed over the last 80 years in the US. We went from toxic doses (50,000 – 300,000 IU/day) in the 1930s, to close to homeopathic doses in the 50’s to 90’s (400 IU/day) and we are beginning to take physiologic doses (1,000 – 5,000 IU/day) in recent years. If you want to read details of how that happened, read the newsletter below:
Recently the British Medical Journal reported on a case of vitamin D toxicity in a four-year-old autistic child. The article is open access:
The child presented with a 3-week history of vomiting, loss of appetite, constipation, excessive urination, excessive thirst and a loss of 7 pounds in the previous 2 weeks. His serum calcium was 16.3 mg/dl and his 25(OH)D was 853 ng/ml. The parents report they were giving him a total of 3,000 IU/day of vitamin D, but the authors do not say how long he had been on the vitamin D supplement. He was treated for two weeks, until his serum calcium was normal and then discharged. The authors do not report if a 25(OH)D was done on discharge, nor whether the vitamin D supplements his mother gave him were capsule or drops. They do not give his weight, only that he had lost 7 pounds during his toxicity. The authors did not assay the vitamin D supplements to see how much vitamin D they actually contained.
Does anyone see a problem here? The average four-year-old weighs 40 pounds. What 25(OH)D would you expect if a 40-pound child took 3,000 IU/day? 854 ng/ml? Not a chance. What happened here, and what I reported to the authors, was like the Gary Null case above, there was a manufacturing error. This child was probably getting 2,000,000 IU/day to obtain a 25(OH)D of 853 ng/ml.
That means there is a vitamin D manufacturer out there who is making an order of magnitude mistake. It means other children will become toxic. I reported my suspicion to both authors, but they did not agree to contact public health. I wrote a letter to public health in the UK warning about this.
Cases like this explain why we recommend Biotech Pharmacal’s vitamin D3 supplements. Their in-depth quality assurance process allows individuals to feel comforted by the fact that the supplement contains exactly the same amount as that on the bottle’s label.