Concerns 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," causing some people to go to extreme lengths to avoid such chemicals.
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."
Gribble says it's impossible to have products made without chemicals because nearly every substance contains molecules made through chemical reactions. We are breathing in chemicals all the time from car exhaust to perfume fragrance, Gribble points out.
What's more, all-natural foods aren't necessarily safer or better for you than those with artificial chemicals, he says.
In a recent paper published in the journal Food Security, Gribble makes the claim that artificial pesticides and fertilizers used in the agriculture industry pose little risk in the small amounts we typically ingest.
"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."
Gribble said he worries more about organically grown produce, because farmers avoid using synthetic fertilizers in favor of cattle manure which 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 said, people may face a higher risk of contracting a food-borne illness.
Those who take pains to avoid artificial sweeteners may want to reconsider if they don't have any gastrointestinal problems from them, Gribble says. These substances were tested and deemed to be safe — at the amounts most Americans typically ingest — before they were allowed on the market.
"I have two to three diet sodas a day," he said.
What about all those artificial flavorings or preservatives such as MSG added to foods? "I don't think about them too much," Gribble said, nor does he read food labels to avoid them or order his Chinese food without MSG.
There are, though, some chemical compounds that Gribble does try to limit because they've been deemed to be toxic in moderate amounts. Certainly cigarette smoke would fall into that category, but also soot from the fireplace. He also tries to limit his intake of steak, chicken, and vegetables that have been charred on the grill, and burned toast.
Ashes from these foods contain cancer-causing chemicals called free radicals.
He's also not a fan of tuna or swordfish because they often contain mercury from pollutants in the ocean. "A pound has a lot of mercury, which accumulates in tissues over time and can be very toxic. Smaller fish are OK."
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.
I asked 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.”