Vitamin D: Toxicity and FAQ

Risks, Facts, Resources & Links

Toxicity

Each time new research comes out people get concerned about the toxicity of vitamin D, but the old wife’s tale about high vitamin D levels being toxic is completely untrue. The main fear is that vitamin D is a fat soluble vitamin and isn’t quickly excreted from the body when there is excess. While this concern is valid for other fat soluble vitamins like vitamin A, it does not appear to apply to vitamin D.

If you have kidney stones or other kidney disorders you especially need to consult with your doctor before starting supplementation. There are some drug interactions with vitamin D supplements as well, so if you are on prescriptions ask your doctor and do some research.

Itchy skin, lack of appetite and excessive urine are all signs of Vitamin D toxicity. There are no good studies that define toxic levels, but a study did show that 10,000 IU per day was safe for a period of 6 months. Nobody has ever been poisoned by the sun because your body has control mechanisms built in, but you can take too much by mouth.

To my knowledge there hasn’t been a death from vitamin D toxicity reported in the medical literature. The closest a family came to having a problem was a when their housekeeper accidentally cooked all their meals with a horse supplement that contained about 50,000,000 (fifty million) times the RDA for humans. She thought it was cooking oil. The family didn’t die, and after treatment didn’t have any long term affects.

There is some research about the levels of vitamin D being in proper proportion with vitamin A. Unfortunately, we do not yet know the optimal ratios between these two vitamins, but it is clear that nearly all cod liver oil products supply A and D in levels that do not appear to be ideal. It’s highly unfortunate, but many people in developed countries are potentially sabotaging the multitude of health benefits they could receive from adequate vitamin D by taking excessive amounts of vitamin A, either in the form of multi-vitamins or cod liver oil. I still recommend fish oil supplements, but keep in mind that dosing should be strictly followed to avoid these ill effects.

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