Poison or Panacea?

Poison or Panacea?

In the summer of 1984, while attending Boy Scout camp, one of our counselors gave a talk on food safety and kitchen cleanliness. At some point he mentioned botulism, a food-borne illness caused by bacteria, and told us that the botulinum toxin was so potent that a single cup (8 ounces) would be enough to kill everyone on the planet.

Naturally, my young mind pictured people lining up, each taking a tiny sip from a cup and immediately keeling over. The image was absurd, but the lesson stuck: some substances are unimaginably dangerous.

But what if I’d had a glimpse of the future instead?

I would have seen people lining up to inject this very toxin into their bodies—voluntarily. My reaction would have been immediate: “They’re mad. They’ve all gone mad!” And I probably would have spent the rest of camp confined to the medical tent. And really, who could blame me? Botulinum toxin is among the most potent poisons known, lethal at vanishingly small doses—yet today it’s widely used to treat a variety of medical conditions, with few if any side effects.

So what changed?

Is the toxin neutralized? No.
Is it chemically altered? No.
It’s the same substance.

The difference, it turns out, is dosage.

For botulinum toxin, the median lethal dose for an average adult male is roughly 150 nanograms (a nanogram is one billionth of a gram). A standard 100-unit vial of Botox contains less than one nanogram—about 0.73 nanograms. Even aggressive cosmetic treatments may involve around 150 units, or a vial and a half, still nowhere near dangerous levels.

Botulinum toxin works by blocking nerve signals to muscles, causing temporary paralysis. In large enough doses, this can affect the lungs or heart and be fatal. But when administered in extremely small, precise amounts, and targeted to specific muscles, the same effect can smooth wrinkles, prevent migraine headaches, treat muscle spasticity, and provide a host of other therapeutic benefits.

The first approved therapeutic use of Botox came in 1977, for the treatment of eye muscle disorders. From there, researchers began exploring beneficial uses of other toxins—both venoms (toxins injected by organisms like snakes or spiders) and poisons (toxins produced by plants or ingested). One early success was captopril, a blood-pressure medication derived from the venom of the Brazilian pit viper, approved in 1980. Many others followed.

Ziconotide, derived from the venom of the cone snail, is a powerful pain reliever. Exenatide, a peptide found in the saliva of the Gila monster, is used to treat type II diabetes. The foxglove plant produces compounds used to treat congestive heart failure and irregular heartbeat.
The rosy periwinkle plant is the source of vincristine and vinblastine, key drugs in treating childhood leukemia.

Even fluoride—though not a biological toxin—follows the same rule. In small amounts, fluoride strengthens tooth enamel and reduces decay. At higher, sustained levels, it can cause harm. The CDC and Department of Health recognize 0.7 milligrams per liter as the optimal concentration for community water fluoridation, while long-term exposure above 2.0 mg/L has been shown to be harmful.

Despite this, some detractors insist that any amount of fluoride is dangerous. They point to effects seen only at sustained high doses, while ignoring decades of robust scientific research demonstrating fluoride’s dose-dependent nature. They advocate for a fluoride-free lifestyle—but that’s easier said than done.

Fluoride occurs naturally in groundwater, rain, seawater, and surface water. As a result, it’s present in many foods: spinach and other leafy greens, potatoes, carrots, coffee and tea, seafood, beans, chard, grapes and raisins, almonds, walnuts, and many more. Avoiding fluoride toothpaste is one thing; completely eliminating fluoride from your body would be nearly impossible.

Anti-fluoridation activists have recently claimed a victory in their effort to pressure the EPA to remove fluoride from drinking water. In Food & Water Watch, Inc. v. EPA, the plaintiffs relied heavily on a controversial study whose own authors cautioned that it “cannot be used to draw any conclusions regarding low fluoride exposure concentrations, including those typically associated with drinking-water fluoridation.” Nevertheless, the court ruled in their favor, a decision now under appeal. But it does raise an important question: why are courts, rather than scientists and public-health experts, deciding matters of toxicology?

History suggests the legal system is not infallible. (Anyone remember O.J. Simpson?)

There is no shortage of substances—natural and synthetic—that enter our bodies every day and could cause harm. Drinking water may contain trace, EPA-allowed amounts of arsenic, nitrates, or uranium, yet no one is demanding their levels be reduced to absolute zero. Why? Because zero risk is not achievable, and policy is built on evidence of actual harm, not theoretical danger.

Worrying about the impossibility of eliminating every potential exposure would drive anyone mad. And besides, too much worrying leads to wrinkles.

Ooooh, I have just the thing for that!

- Dr. McGann