Which causes more harm?:
a. Pesticides and other synthetic chemicals sprayed on fruits and vegetables, or
b. Salmonella and other microbes living on such produce?
The answer is “b’’, but most of us are far more concerned about pesticides than food poisoning. Misperceptions about the dangers caused by the use of man-made chemicals in our environment has caused what Gordon Gribble, a professor of organic chemistry at Dartmouth, calls a “colossal mess.’’
We are breathing in chemicals all the time from car exhaust to perfume fragrance. Wine aroma, Gribble said, has more than 20,000 different chemicals that we inhale in small amounts only to exhale them again or have them quickly metabolized by the body.
Yet some people take pains to avoid all things that they identify as dangerous chemicals to the point that it impairs their daily lives, a phenomenon known as “chemophobia’’. It has spawned a multi-million dollar industry marketing foods and cleaning products labeled “all-natural’’ or “chemical free’’.
It’s actually impossible to have products made without chemicals because nearly every substance contains molecules made through chemical reactions. And all-natural foods aren’t necessarily safer or better for you than those with artificial chemicals.
In a recent paper published in the journal Food Chemistry, Gribble pointed out that anything can be toxic if ingested in high enough quantities, even substances we rely on to live such as water or salt.
Dozens of fruits, vegetables, and spices contain natural pesticides that at high levels cause cancer in rats and mice. These include brussel sprouts, apples, broccoli, mushrooms, and black pepper. Plants that didn’t contain compounds to kill off insects often became extinct, Gribble pointed out, while cocoa and tobacco plants – which contain the pesticides caffeine and nicotine – thrived.
We wouldn’t want to forgo the enormous health benefits from fruits and vegetables. What’s more, in the small amounts we typically eat, natural pesticides in plants pose little health risk, and the same can be said for artificial pesticides and fertilizers used in the agriculture industry.
“Any synthetic pesticide residues on fruits and vegetables are minor, and today’s products are extremely safe,’’ Gribble said. “We don’t use dangerous chemicals like cyanide anymore.’’
In fact, he said, he worries more about organically-grown produce because farmers avoid using synthetic fertilizers in favor of cattle manure; this can be contaminated with listeria, e. coli, and other pathogens that reside in the animal’s feces. “If the manure hasn’t been sanitized to kill these germs,’’ he explained, people may face a higher risk of contracting a food-borne illness.
For those who take pains to avoid artificial sweeteners such as Splenda or Nutrasweet, Gribble said those fears are misplaced, as well, since these substances are extremely safe at the amounts most Americans typically ingest.
“I have two to three diet sodas a day,’’ he said. What he does avoid is steak, chicken, and vegetables that have been charred to a blackened state on the grill – and burned toast.
Ashes from these foods contain cancer-causing chemicals called free radicals. “If you take soot and rub it on the back of a mouse, the animal will get skin cancer,’’ Gribble said. (Yes, you should wash your hands thoroughly after cleaning out the fireplace.)
If you must eat crispy ribs, blackened marshmallows, or charred bacon once in a while, chase the meal with a glass of orange juice. The vitamin C and other antioxidants in the juice can help neutralize all those free radicals, Gribble said.
He’s also not a fan of tuna or swordfish. “A pound has a lot of mercury, which accumulates in tissues over time and can be very toxic. Smaller fish are okay.’’ Other researchers have said, however that the benefits of heart-healthy omega-3 fats contained in these fish outweigh the risks of a small exposure to mercury as long as you limit your intake to no more than 4 ounces twice a week.
What about all those artificial flavorings or preservatives such as MSG added to foods? “I don’t think about them too much,’’ Gribble said. He doesn’t read food labels to avoid them or order his Chinese food without MSG.
I ask Gribble what he thinks about other man-made chemicals that have raised a firestorm of concern such as bisphenol-A found in hard plastics and the lining of cans. “It doesn’t appear to cause cancer, but the jury is still out on how it interferes with our hormonal systems.’’
He has no quibble with environmental groups that successfully lobbied manufacturers to remove BPA from baby bottles and infant formula cans. “We have to worry more about babies,’’ he said, “since their body systems are still undergoing crucial development during the first few years.’’