When Franklin Delano Roosevelt became America’s 32nd president in 1933, he famously rallied his countrymen to sanity by assuring them that “the only thing we have to fear is fear itself—nameless, unreasoning, unjustified terror which paralyzed needed efforts to convert retreat into advance.” Seventy-eight years later, "nameless, unreasoning, unjustified terror" neatly summarizes our food-fear environment. If you regularly digest information from Michael Pollan or the Center for Science in the Public Interest, a Harvard risk-assessment expert would like to have a word with you.

David Ropeik, whose two books on risk are must-reads for fans of reason and sanity, wrote a column on Friday for London’s Guardian newspaper. Europe is in the midst of a deadly E.coli outbreak (presumed to be vegetable-related) which has killed 23 people. Yet Ropeik argues that most of us, led around by the nose by our emotions, wind up less healthy because we overreact to bad news about food safety:

[T]he actual danger for any vegetable-eating European, even in Hamburg or other places where the cases have been concentrated, is low. Statistically. Scientifically. But then, we don't just use scientific evidence or statistical probabilities to figure out what's dangerous. Risk perception is a mix of facts and feelings, intellect and instinct, reason and gut reaction. And in many cases, the feelings/instinct/gut have the greater influence …

[T]he gap between our fears and the facts … presents its own, very real risks. In this case there are a lot of people who aren't eating vegetables – any vegetables. That's not good for their health. Hundreds of thousands of people are more worried than necessary, and more worried than normal, and chronic worry produces the myriad damaging health effects of stress (including a weakened immune system, which makes us more vulnerable to the very bacterial infections about which people are worried in the first place).

There may be a parallel in the movement to turn ordinary consumers into vegans and vegetarians. A PETA vice president claims today that ditching meat and dairy can lower your cancer risk. But by how much? (And can you trust PETA’s assessment to begin with?) Is it akin from nudging “1 in 10 million” down to “1 in 8 million”? And is that worth the other health trade-offs? A study reported today shows that vegans can be iodine-deficient. And more prone to heart disease. And more likely to deliver babies with birth defects. One French woman is even facing trial for the death of her breast-fed baby because her own vegan diet left her (and her milk) vitamin-B12 deficient.

We’ve seen this same dynamic at work in Americans’ irrational fear of seafood. There are huge health trade-offs when pregnant women (and their unborn babies) are denied the proven benefits of omega-3 fatty acids because so many people now fear vanishingly small traces of mercury. (To gauge your actual risk, see www.HowMuchFish.com.)

The bottom line is—or should be—that our food is safer today than at any time in history (thanks to refrigeration, epidemiology, meat inspections, municipal health codes, and gobs of other modern advances). Ropeik is right when he observes: “If you think a risk can happen to you, it doesn't matter what the numbers say.”

But it should matter. At least for anyone who wants to avoid becoming a slave to whatever the Internet says we should fear today. Or tomorrow.