Vitamin D Toxicity: What You Need to Know

Given my very bullish recommendation on vitamin D supplementation, it’s not surprising that more than a few people have asked me if taking too much vitamin D can be toxic.

The answer is yes.

(And please don’t stop reading here.)

The question became a lot more than theoretical when a  case involving the well-known health guru, Gary Null, came to light recently.

Apparently Null became very very sick from taking too much vitamin D.

This case was even weirder because the source of this vitamin D was his own product, “Ultimate Power Meal”.

Ultimate Power Meal was labeled as containing 2,000 IUs of vitamin D, an amount I personally feel is the minimum everyone should supplement with (but that’s just my opinion).

Unfortunately, his supplier and formulators made a bit of a mistake and left off a couple or three zeros.

Ultimate Power Meal contained 2,000,000 —  that’s two million — IUs per serving, not two thousand. That means in a month, he consumed 60 million IUs; just for the record, 10,000 IUs per day (the amount I take) adds up to, let’s see…300,000 IUs a month, about 1/200 the amount Null consumed, and one hundred times the amount someone popping a 2,000 IU pill on a daily basis would consume.

For the record, Null fully recovered within three months after stopping the defective supplement.

Nonetheless, the question remains: can vitamin D be toxic? And the answer is, “of course”, just as water and oxygen and omega-3’s can be toxic, but the number of cases in which that happens are about as common as an appearance by Bill Clinton at a fundraiser for Sarah Palin. (There was a case of death from the overconsumption of water a couple of years ago during an insane shock-jock radio stunt — try to name another. I can’t.)

The Vitamin D council- not exactly a radical, wild-eyed group — did a little digging and found studies going back to the 30’s in which patients were medically treated with two hundred thousand IUs a day (for arthritis). (Ref: Dreyer I, Reed CI. The treatment of arthritis with massive doses of vitamin D. Archives of Physical Therapy. 1935;16:537- 43). While the vast majority of patients improved substantially, about 10% got sick. The doctors in charged simply took the patients off that dose, told them to drink lots of fluids, and ultimately all recovered quite nicely.

Other studies going way back show administration of what we would consider insane amounts (ranging from 150,000 IUs to 300,000 IUs a day, for extended periods). Most showed no ill effects over a short course of treatment (remember, Null took 200,000 IUs daily for over three months.)

Now listen carefully. I am not — repeat not — in a million years recommending any dose like that, or anything even near it.

But I think it’s really important to look beneath the inevitable headlines and sound bites about the Null case (“Vitamin D is toxic!” “Health guru Gary Null made terribly ill by vitamin D”, etc) and realize that we are talking about thousands — repeat thousands — of times the dose I and other health professionals have been recommending.

Vitamin D — like water, oxygen and omega-3’s — can theoretically be a problem but the key word is theoretically. If anyone knows of a single case report published anywhere in the world showing serious problems with a dose of 8-10,000 IUs a day, I’d like to hear about it. And I’ll personally send a “reward” (a set of any four of my books you’d like) to anyone who can find a substantiated report of a problem at the 2,000 IU level (which now considered safe by even the Institute of Medicine).

For the record, a blood test for vitamin D is easily available and highly recommended. It’s called a 25-Hydroxy-vitamin D test, and the majority of people in this country come up low. By even the most outdated and conservative standards, less than 37.5 is generally considered inadequate, but all the experts I know and respect are looking for numbers more in the range of 75-80.

Want to know what’s considered “potentially toxic”? Consistent levels of greater than 500.

Also for the record, symptoms of “toxicity” (as listed by the Dietary Supplement Fact Sheet, National Institutes of Health, Office of Dietary Supplements) are: nausea, vomiting, poor appetite, constipation, weakness, and weight loss. (More seriously it can cause elevated blood levels of calcium, but please remember the doses we’re talking about here!)

Very few foods in nature have a lot of vitamin D and our national sun phobia hasn’t helped the situation.

Considering the incredible benefits of vitamin D — improved bone health, mood, physical performance, lowered risk of dying from all causes, improved immune system function, reduced risk of cancer and MS, even increased likelihood of benefiting from a weight loss program! — I wouldn’t even consider not supplementing on a daily basis.