Can you actually overdose on vitamin D?

I recently came across a disturbing report that claimed excessive vitamin D caused “kidney failure” in a 54-year-old Canadian man.

The headline certainly caught my attention and initially concerned me, as it appeared in the highly respected Canadian Medical Association Journal.

But when I read through the actual medical literature, I discovered that the man didn’t suffer from kidney failure, as the headline claimed. Even more, he had several other serious risk factors that probably contributed to his kidney issues.

So, here’s the real story…

Risk factors hidden in back story

According to this report, a 54-year-old Canadian man with high cholesterol, high blood pressure, and gout had just returned home from a two-week vacation to Southeast Asia.

While on vacation, the man had spent six to eight hours a day sunbathing, which can cause severe dehydration and, by itself, lead to kidney problems if you’re not careful. In addition, he was taking diuretics for his high blood pressure, which can also cause dehydration and lead to kidney problems. Plus, the man had a family history of kidney disease—with two first-degree relatives requiring dialysis by the age of 60.

So, when the man returned to Canada, he wasn’t feeling well and went to his family doctor for advice. After ordering a routine blood test, the doctor learned that the man had high creatinine.

Now, high creatinine is certainly a problem that can indicate impaired kidney function—but it’s nowhere near “kidney failure,” as described in the report’s headline. The man didn’t even need dialysis.

As a precaution, the doctor immediately took the man off his prescription drugs for high cholesterol (disasters in a pill, to begin with), high blood pressure, and gout—all of which can damage the kidneys.

But the man continued to show signs of kidney toxicity, so he was sent to a kidney specialist.

The specialists then learned the man had been taking 8,000 to 12,000 IU of vitamin D daily over the last 2.5 years. So they tested his blood levels of the nutrient.

It turns out, the man’s blood measurement of 25-hydroxyvitamin D3 was 241 nanomoles/Liter (nmol/L), which is considered a “toxic” level. So, the specialists advised him to stop taking vitamin D supplements and initiated drug treatments to lower his vitamin D blood levels. (Although this outcome is extremely rare, it’s another reason why I always recommend asking your doctor to check your vitamin D blood levels twice a year.)

Inaccurate headline skews the story

After this whole ordeal, the man was left with stage 3B kidney disease, which essentially means his kidneys don’t filter as efficiently as healthy kidneys. Clinically, experts categorize this stage as moderate kidney disease.

Patients can manage 3B kidney disease by seeing a doctor for medical monitoring, maintaining a healthy diet and lifestyle, and taking prescription medications (if warranted).

Furthermore, this stage isn’t categorized as kidney failure. And it doesn’t require renal dialysis.

All in all, it’s incredibly frustrating that a well-respected medical journal would inaccurately report that a man’s “kidney failure” was due entirely to “excessive” vitamin D supplementation. Utter nonsense!

What about the patient’s documented, long-term risk factors—such as taking several prescription drugs known to damage the kidney? Not to mention his immediate family history of kidney disease and kidney failure.

And what about the short-term risk factors—such as sudden, excessive sun and heat exposure and dehydration?

Indeed, the man’s toxic vitamin D levels could very well have been caused by suddenly spending eight hours a day sunbathing—which triggers the skin’s natural production of vitamin D—over two weeks in tropical Southeast Asia.

In my view, this sudden, prolonged, intense sun exposure probably sent his body’s production of vitamin D into overdrive, pushing his blood levels of the nutrient much higher than any dietary supplement could ever achieve.

Plus, with a strong family history of kidney disease, you simply have to be more cautious about the drugs you take, sun exposure, and dehydration.

Unfortunately, this report didn’t account for any of those risk factors and placed sole blame on taking 8,000 to 12,000 IU daily of vitamin D.

In the end, I suggest we set aside this highly unusual case where doctors ignorantly blamed vitamin D and ignored all the other plausible, contributing factors.

Because the science tells us you can safely…

  • Continue to supplement daily with 10,000 IU of vitamin D. It will help you achieve optimal blood levels of vitamin D (50 to 60 nanograms/milliliter [ng/mL]), which are required for good health, sharp cognition, and protection against chronic disease.
  • Continue to spend 10 to 15 minutes (not eight hours) in the sun daily without (I will tell you all about the problems with sunscreens in the upcoming August 2019 issue of my Insiders’ Cures newsletter. If you’re not yet a subscriber, now is the perfect time to get started!)
  • Ask your doctor to check your blood levels of vitamin D twice a year. (Ideally, once at the end of summer and again at the end of winter.) This safeguard will protect against the remote possibility of pushing your vitamin D levels too high. In addition, you should always discuss your family history and supplement use with your personal doctor.

There is a wealth of science backing up these recommendations. In fact, I’ve probably written more about the science of vitamin D than any other single topic in the seven years since starting my Daily Dispatch.

To educate yourself on all the cutting-edge science, you can search my archives by typing “vitamin D” into the “search” box at the top, right corner of my home page at www.DrMicozzi.com.

Sources:

“Use of vitamin D drops leading to kidney failure in a 54-year old man.” Canadian Medical Association Journal, 2019; 191(14): E391-394. doi.org/10.1503/cmaj.180465

“Excess vitamin D linked to kidney damage.” Medscape, 4/8/19. (medscape.com/viewarticle/911444)


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