Setting the record straight on “too high” vitamin D dosages

How mainstream medicine’s accusations can harm your health

When it comes to your health, springtime means your body is once again able to produce vitamin D with ease. As you may recall, for latitudes north of Atlanta (or north of LA, if you’re on the west coast), the sun’s ultraviolet B (UVB) rays—which your body uses to activate vitamin D production—only penetrate the earth’s atmosphere from April to October.

While I recommend soaking up the sunshine during warm weather months to allow your body to create its own D (aim for 15 to 20 minutes a day without sunscreen), there is one catch… Even in the spring and summer, UVB rays only reach the earth’s surface between 10 a.m. and 2 p.m. So that tight four-hour window is your sole opportunity to “naturally” increase your D levels.

That’s the reason why it’s so important to supplement with vitamin D year-round. And, based on all the latest science, I recommend 10,000 IU of this vital vitamin every day.

Of course, mainstream medicine scoffs at this supposedly “high” level, and issues all kinds of dire warnings. But I think that’s just a plot to scare people away from improving their health naturally.

Not to mention, it preys on the fact that most people (including many well-meaning primary care doctors) don’t understand how D is really measured. So let’s set the record straight…

The complicated universe of supplement measurements

Unlike most other vitamins, minerals, and herbal supplements, vitamin D has been measured in IUs, or international units, rather than milligrams or micrograms.

The metric measurements indicate the relative potency of a substance, especially when dissolved in the human body, which is made up of kilograms of mostly water.

The bottom line? When you convert IU into more commonly used measurements, it’s actually a very, very small amount.

What’s an IU anyway?

As I mentioned earlier, vitamin D has been measured in IUs rather than in metric units. IUs don’t refer to mass or volume that we can physically see or feel, as in the case with milligrams or micrograms. Instead, an IU measures the potency, or biological activity, of a compound.

If IUs were translated into the metric system, the doses would appear to be very tiny. In fact, the 10,000 IU of vitamin D I recommend per day is only 250 micrograms.

To put that into perspective, you often see recommendations for vitamin and herbal supplements—and even drugs—of 250 milligrams. That dose is 1,000 times bigger than my vitamin D recommendation.

The units for measuring actual blood levels of vitamin D are also miniscule. The most common measurement is nanograms per milliliter. One nanogram equals 1 trillionth of a gram. And every 100 IU of vitamin D you ingest raises your blood levels by one nanogram per milliliter.

When I first started working in laboratory medicine as a clinical chemist and toxicologist (for the new McDonnell Douglas lab using NASA technology), it wasn’t even possible to measure anything in the blood or tissues in such small “nano” levels.

Vitamin D overdoses are virtually unheard of

It’s amazing how much good the body does with such small amounts of vitamin D.

What’s even more amazing is that sunlight actually destroys any excess vitamin D that happens to be made in the body (and is not stored by the organs). That’s why you can never get too much sunlight, at least in terms of vitamin D production.

Because of these natural biological checks and balances, clinical vitamin D overdose is one of the rarest medical conditions in the world. And yet, the government wants doctors and patients to think taking any amount of vitamin D over 4,000 IU (a measly 100 micrograms) is “high.”

Which raises the question: Does the arbitrary IU measurement—rather than the more common metric measurement—contribute to the medical myth of vitamin D “overdose” and toxicity? I certainly think so…

How this vitamin overpowers prescription drugs

Even when you look at it from the mainstream medicine perspective, the fixation with “high” doses of D doesn’t make sense.

When it comes to prescription medications, pharmacologists use what’s known as a therapeutic index to determine the relative safety of a drug. This index is the toxic dose of a drug divided by the therapeutic dose.

For instance, digitalis, a drug for the heart, has a therapeutic index of only 2 or 3. That is, taking just two or three times the therapeutic dose can make you sick—or even kill you (as was the case with my late neighbor, as I mentioned on page 3). You can just imagine how many other drugs have an even scarier therapeutic index.

So what’s the therapeutic index of vitamin D?

For bone disease, it’s at least 300. That is, the dose needed to cause any toxicity is 300 times more than the dose effective for preventing or treating bone disease.

For preventing and reversing chronic diseases like heart disease, diabetes, cancer, and Alzheimer’s, just to name a few, vitamin D’s therapeutic index is at least 20. That’s quite a good margin of safety for vitamin D in comparison to most drugs.

Why the concept of “high” D doses is so ridiculous 

Imagine if you took 20, or even 100, times the recommended dose of a prescription or over-the-counter drug.  It’s very unlikely you’d survive the experience. In fact, as a medical examiner and consulting forensic pathologist, I investigated many fatal poisonings due to that very scenario.

And let’s not forget to mention how the government attempts to assuage our concerns about pesticides and chemicals in our food and consumer products by referring to the concentrations in parts-per-million (ppm) or -per-billion (ppb) to make them seem quite low. (Despite the fact that these chemicals are extremely toxic, even in trace amounts.)

And yet somehow, the government-medical-industrial complex is unwilling to apply the same logic about levels of a healthy nutrient like vitamin D—even when 10,000 IU translates to less than 100 nanograms in a milliliter of blood.

For the time being, stick to a daily dose of 10,000 IU and enjoy time outside without worry. Look for vitamin D3 in an easy-to-use liquid form, combined with astaxanthin (which carries strong benefits for your vision, as I discuss on page 7).