In our last column, we mentioned just a few of the unsuspected adverse effects of vitamin supplementation.

To reiterate: vitamins are vital to human life within a certain range of dosages. Even higher doses than the "Recommended Daily Allowance" (RDA) are routinely employed for some categories of medical patients, such as pregnant women (folate), people on poor diets, alcoholics (B1), and the elderly (D and B12).

Note that I'm just addressing vitamins here, not minerals or the hodgepodge of other chemical "supplements" that are hyped for their supposed ability to prevent old age, bad breath or cooties. That's a whole 'nother can of scam.

It is becoming apparent that relying on vitamin pills and potions as some sort of broadly based guarantor of good health is largely futile at best, and dangerous at worst.

They're not cheap, but they're easy. Not getting enough exercise? No time to eat well? Worried by your smoking? Have we got a pill for you!

Incorporating rational levels of supplemental vitamins and minerals directly into common foodstuffs has been a valuable practice. We routinely "fortify" milk and cereal, which has reduced iron-deficiency and rickets in children, among other things.

In other cases, "fortification" with vitamins is just part of a sales pitch based on a con.

Nobody who can afford high-priced flavored water is likely to depend on it to keep from becoming vitamin-deficient. These small additional amounts just don't make a difference, good or bad. The scam comes when the sellers exploit another common belief -- that vitamins not only help the body function over the long term, but also produce instant energy. That is, they're presumed to provide an immediate boost in mental and physical power, like amphetamines.

That's not the way these chemicals work, but the ploy sells worthless nostrums at expensive prices.

Though they're otherwise placebos, many "energy drinks" do contain pharmacologic doses of caffeine and related xanthine chemicals, such as theobromine in tea and caffeine-boosters from guarana. The subjective combined effect of these mixtures does differ somewhat from that of plain caffeine in coffee, but not to the extent of manufacturing energy from a vacuum. The vitamins themselves are irrelevant.

Apart from cynical sales pitches, where did we get the notion that extra vitamins are so doggone good for us?

Science's discovery of vitamins and their roles in human health tempted some into premature speculation -- since vitamins are necessary for life, life would be even better we if swallowed even more vitamins! It's the "more is better" philosophy, and we apply it to many things other than vitamins.

As nutritional and medical sciences intersected, we discovered the "free-radical" concept -- chemicals in the body that can cause injury, such as heart disease and cancer, by destroying ("oxidizing") good chemicals that we need. Some vitamins have "anti-oxidant" properties -- at least, they do in the test tube. Maybe that means that if we flood our bloodstream with high doses of these vitamins, we might prevent heart attacks and cancer?

That provided a theoretical basis for using supplements, but did it work out in practice?

At first, it seemed to. Large-scale studies of diet and disease showed that people among the least likely to suffer from those "oxidative" diseases ate more foods high in certain vitamins. (But were also likely to follow healthier lifestyles in other respects.) Maybe we could just skip the broccoli and get our cancer-fighters in a pill?

Or maybe not. As the studies summarized in The Medical Letter suggested, the vitamins we concentrate in a convenient pill simply don't exert the same effects as the vitamins eaten in regular food.

There are a couple reasons for this. One is simply the dose, the amount. Pills don't mimic diet. Even foods touted as "rich" in a given vitamin do not contain nearly as much of that vitamin as a few pills do. Foods do allow us to meet our RDAs, which is all we usually need. (Treating isolated deficiencies requires higher dosing.)

But for most or all of these vitamins, more is not better. Our biologic processes evolved in an environment that is reflected in our biochemistry. That, I propose, is what's "natural" about vitamins. When we try to go Mother Nature one better, up the ante with concentrates and pills, we are doing a very unnatural thing. When we don't respect our bodies' evolved wisdom, all the bets are off.

At the heart of this matter, however, might rest an important principle that modern medical science has largely forgotten: the "ensemble effect."

Simply put, one chemical's full biological function depends on its context, its chemical environment.

Western pharmacology uses an analytic approach to drug assessment -- identify all the different chemicals present in a plant or fungus, say, and then test each one in isolation. This is useful for determining how one drug is metabolized and excreted, dose ranges, side-effects and mechanisms of action, but it paints an artificial picture.

When certain drugs are removed from their botanical context, they function differently. Such a context can include dozens of other chemicals which interact with the "target" drug -- flavenoids, polyphenols and other active agents. They "potentiate" (2+2=5) or "mitigate" (2+2=3) each other.

Since this ensemble of chemicals in foodstuffs is really responsible for the benefits popularly attributed to a single agent, e.g. a vitamin, it's no wonder the diet can do what the pill can't.

Jon Hauxwell, MD, is a retired family physician who grew up in Stockton and now lives outside Hays. hauxwell@ruraltel.net