“D” Gets an Incomplete

“To coin a phrase, the jury is still out on Vitamin D.”—By Sanford Rose

Dolors & Sense

By Sanford Rose

KISSIMMEE Florida—(Weekly Hubris)—5/5/2014—To coin a phrase, the jury is still out on Vitamin D.

Perhaps the most hyped vitamin of the past decade, D helps in the absorption of calcium and phosphorous.

The body makes it from sun.

But it doesn’t usually make enough of it in northern latitudes because the sun isn’t strong enough most of the year.

Of course that doesn’t mean people in those latitudes must take supplements.

We can get our D from diet—e.g., a lot of sardines, wild salmon, mushrooms, and fortified milk products. Or we can use “safe” tanning beds.

The point is: we don’t.

Many medics argue that we are deficient, although the definition of deficiency varies widely.

If, indeed, we are, what price do we pay?

We all learned that  D prevents rickets.

According to its hierophants, it does far more. They argue that, among other things, it:

Prevents falls and fractures in the aged.

Promotes cardiovascular health.

Guards against cancers of the colon, breast, pancreas, and prostate.

Fights depression.

Protects against multiple sclerosis and other auto-immune diseases.

Wards off the flu and colds.

And just plain cuts total mortality.

(Probably also cures writer’s block.)

Observational studies seem to bear out some of these claims.

One study shows mortality falling as D levels increase until a plateau is reached at 30 nanograms per milliliter. Past that level, mortality starts rising again.

But randomized-control trials—the gold standard of medical evidence—do not support many of the more extravagant assertions about D’s benefits.

To be sure, it seems to prevent falls and fractures in the elderly. But only if combined with calcium. And not too much calcium, which can lead to cardiovascular problems that obviously cancel out the orthopedic benefits.

And there is one trial showing a 9 percent statistically significant decline in total mortality among women randomized to D ingestion relative to those given a placebo.

But there is no credible evidence that D supplementation confers any of the other benefits. Indeed, one large study showed that it had absolutely no effect at all on the incidence of colds.

There is a mammoth trial under way, testing many of the above claims. But results won’t surface for another five years.

If, in the interim, you feel the need to take a daily D supplement, take only about 800 IUs and take it with calcium and those other co-factors that potentiate its benefits—e.g.,Vitamin K2,  magnesium, zinc, and boron.

(Vitamin K2 allegedly prevents the calcium, the absorption of which D facilitates, from being deposited in the organs, where it can do harm.)

And avoid taking a big bolus. Take a divided dose of D, calcium citrate, magnesium, and K2 with every meal.