Six Commonly Missed Diagnoses: Vitamin D Deficiency

Much of medical care is hampered by the black-and-white thinking of doctors. You either have a condition (symptoms confirmed by positive tests) or you don’t (symptoms, but no useful test results, and therefore “nothing’s wrong with you”). Doctors are uncomfortable with grey zones, like when test results seem normal but on closer inspection are normal by just a hairsbreadth.

To some extent the profession has brought this discomfort on itself, relying on laboratory printouts of test results to do their thinking for them. If your numerical test result lands anywhere in the normal range, there’s no visual alert to catch the doctor’s eye. Only when your number lands outside accepted values does the abbreviation ABN (for abnormal) or the words HIGH or LOW appear.

If you watch your doctor’s eyes as she scans your report, you’ll see she’s looking for these prompts to jump-start her decision making. She probably won’t register the actual numerical value, but if she does and sees that your number is barely normal it will likely make her uncomfortable, as doctors everywhere prefer the presence or absence of ABN, like a lighthouse signal in the fog showing the way forward.

Just like last week’s missed B-12 deficiency diagnosis, in which low levels of B-12 were considered officially normal, today’s topic again involves over-reliance on “normal” test ranges. Doing this not only misses many chronic and otherwise undiagnosed symptoms, it also can be dangerous to your long-term health.

Physicians get poor nutrition training
During the utterly mediocre nutritional medicine training fledgling doctors receive in medical school, we’re taught mainly about historical vitamin deficiency diseases, like scurvy (vitamin C), beri beri (thiamine), and rickets (vitamin D). Doctors in training are shown a bunch of photos from the Victorian era and learn that British sailors were nicknamed “limeys” when it was discovered that citrus could prevent shipboard scurvy. Since physicians-to-be are confident they’ll never see these deficiencies in their comfy suburban practices, most quietly place their meager nutrition education on the back burner.

By the way, if you’ve ever wondered why you get so little help from your doctor with nutritional supplements–from a blank stare of ignorance to downright hostility toward all supplements–it’s because medical education spends far more time on vitamin toxicity than deficiency. Virtually every physician mentally associates high doses of vitamin C with kidney stones (a medical myth and totally untrue). Nutritional guru Alan Gaby, MD, always gets an audience laugh from doctors when he says the only vitamin fact he remembered from medical school was “polar bear liver” because all doctors learn this same utterly useless fact: you can get a fatal overdose of vitamin A if you eat it.

Low vitamin D is risky business
In recent years scientists have learned that low levels of vitamin D are linked to a lot more than rickets. Previous health tips have, I hope, made you aware that chronically low vitamin D levels increase your risk of breast and prostate cancer, heart disease, Parkinson’s disease, multiple sclerosis, psoriasis, and poor immune function. Low D also actually appears to accelerate aging. As a result, more primary care physicians are ordering vitamin D levels as part of routine check-ups, and this is a good thing. But when these same doctors accept as normal a test result that’s hanging in the normal range by its fingernails (because the lab printout is lacking LOW or ABN), this is not so good.

In case you once knew but forgot, vitamin D is the sunshine vitamin, so named because it’s manufactured in skin when we’re exposed to sunlight. We also get smaller amounts of vitamin D in foods such as wild salmon, egg yolks, and vitamin D-enriched milk. This enrichment is a holdover from the Victorian era when the main cause of rickets was a low dietary intake of D.

Strictly speaking, by the way, vitamin D is not really a vitamin at all since it can be manufactured by the body. To merit classification as a vitamin, like the B vitamins and C, your body must not be able to produce its own supply. You absorb true vitamins from food or supplements only. Vitamin D is actually classified as a “prohormone,” D converting to a molecule that’s then involved with the absorption and regulation of calcium levels in your blood and bones. Without adequate D, bones fail to develop properly, a condition called osteomalacia (bone softening). The deficiency disease, recognizable by bone deformities like bowlegs, is rickets.

And here’s where the black-and-white thinking of the medical profession comes in. To most doctors, your test result either shows you have a deficiency of vitamin D or you don’t. You’re either at risk for osteomalacia or you aren’t. End of discussion.

But now we know that low levels of vitamin D–even those not low enough to be outside normal range–are linked to a variety of otherwise unexplainable symptoms. Unexplainable because all your other lab tests (including the one for vitamin D) have come back normal, these tests looking for a reason for such vague complaints as “tired all the time,” “no zip,” “feeling achy,” “too many colds”, “sports injuries don’t heal well,” “my skin feels ‘wrong.’”

Vitamin D levels appear on your printout in four groups:
Definitely low: 0-20 ng/mL (nanograms per milliliter)
Acceptable: 20-30 ng/mL
Optimal: 30-100 ng/mL
Toxic: above 100 ng/mL

Being Chicagoans, covered as we are by layers of clothing and living under relentlessly grey skies nine months of the year, most of us have vitamin D ranging between 15 and 25. Results under 25 might prompt your doctor to suggest you add daily supplemental D, but most doctors don’t bother treating anything above that. Yet if you look at the numbers in that wide Optimal range, a truly good level of D should be at least 50 and ideally around 70, certainly a far cry from your doctor’s acceptable 25.

So if you’re feeling “not right” and no one can find anything wrong, get your vitamin D level measured. If you’re not within the Optimal range, take at least 5,000 IU (international units) daily of well-absorbed vitamin D3 such as Bio-D-Mulsion Forte drops or get a prescription for high-dose D (50,000 IU weekly) from your doctor to bring your level up to a healthy range and then see how you feel. You might be very impressed with the results. By the way, most vitamin D capsules don’t absorb very well and hence my preference for drops.

Remember, however, that you can actually take too much Vitamin D, so if you’re getting your levels measured, settle in mid-range of Optimal for the lab your doctor uses. Excessive levels of D have been linked to kidney stones and (trust me on this) you don’t want one.

Even if you’re feeling fine, it’s worth having your D level tested so you can supplement to minimize your risk for the conditions listed above.

Here’s an article on safe sun exposure to produce your own vitamin D, in a piece from the trustworthy Vitamin D Council.

Be well,
David Edelberg, MD