Food Safety: Is It Worth the Worry? : Part 2

by Food and Drug Administration (FDA)

(Page 2 of 3)

A bill sponsored by Representative Henry Waxman (D-Calif.) and Senator Edward Kennedy (D-Mass.) would allow the use of additives and permit pesticide residues that present no more than a risk of one cancer case in a million over a lifetime of exposure. This "negligible risk" standard would replace the much debated Delaney Clause, whose "zero-risk" standard is no longer practical.

When FDA assesses a cancer risk at less than one in a million, it means that at most, there will be one cancer in a million. The risk, in fact, may be closer to zero, causing no additional cancers. "The upper bound nature of these risk estimates are generally misperceived by the public, however," says Scheuplein. "For example, if I say I have less than $1 million in my pocket, people will generally assume that I have closer to about $5 than to $999,000. But with risk, it's different — people generally assume the worst."

Also, risk estimates are averages for a population; they are not tailored to individuals. Rather, an individual's entire exposure history and genetic background probably affect susceptibility to any single carcinogenic chemical.

Natural Versus Man-Made

Scheuplein stresses that the primary threat of cancer from food is the food itself, not pesticides and other contaminants: "The nation's food supply contains a lot of natural carcinogens that dwarf all the synthetic sources."

Carcinogens are found naturally in many spices, in smoked or salted fish, pickled vegetables, corn, peanuts, and broiled or fried protein-rich foods such as beef, pork, eggs and chicken, for example. On the other hand, many foods contain substances such as vitamins A, C and E that seem to have a protective effect against cancer.

In 1981, British investigators Richard Doll and Richard Peto published a 117-page report in the Journal of the National Cancer Institute on "The Causes of Cancer: Quantitative Estimates of Avoidable Risks of Cancer in the United States Today." In their report, commissioned by the U.S. Congress, the researchers attributed 35 percent of cancer deaths at least in part to diet.

Dietary guidelines issued by the National Cancer Institute, the American Cancer Society, the federal government (U.S. Departments of Agriculture and Health and Human Services), and the American Heart Association are all similar in their conclusions about the roles of various foods in promoting or helping to prevent cancer. Emphasis is on reducing fat intake, increasing fiber intake, avoiding obesity, and limiting consumption of alcoholic beverages and of salt-cured, salt-pickled, and smoked fish.

Based on the Doll and Peto numbers and an analysis of the quantity of cancer-causing agents in the diet, Scheuplein concluded that the risk of dying of cancer from dietary exposure to both natural and man-made carcinogens was approximately 7.7 percent. Even this figure reflects a combined effect of the carcinogenic substances in the food and the diet itself — that is, the cancer-causing effect of fats, smoked foods, alcohol, and other substances. The risk from naturally occurring carcinogens alone was at least 7.6 percent, and probably much closer to 7.7 percent.

"Most of the dietary risks are people's personal choices," Scheuplein noted. "They are not imposed on people by corporations. Apparently that's a hard lesson. People want to blame somebody." He added, "I think we should be doing more about diet and less about specific chemical residues. The notion that you can ban one or two of the carcinogens in ordinary food and improve your health doesn't make sense."

This is not to dismiss all concerns about food contaminants, but rather to put these risks in perspective and to examine how public perception of risk differs from scientific assessment of risk. For example, as mentioned earlier, the lifetime risk of death from natural carcinogens in the diet is at least 7.6 percent. Yet people are overwhelmingly more willing to accept these dietary risks than the much smaller risk of cancer from Alar.

Hazard + Outrage = Risk

Why is that? Rutgers' Sandman attributes this seeming paradox to a disparity in what scientists define as "hazardous" and what the public perceives as risk. The environmental risks that will kill us often don't match up with those that most anger and frighten us, he writes in a November 1987 article in the EPA Journal.

"To the experts," Sandman explains, "risk means expected annual mortality. But to the public (and even the experts when they go home at night), risk means much more than that." The "much more" is what Sandman calls "outrage." He maintains that the public pays too little attention to "hazard" or death rate, and the experts pay absolutely no attention to outrage. (See accompanying article.) Not surprisingly, he says, they rank risks differently.

People's concerns are often more a function of outrage than hazard. The risks associated with a high-fat, low-fiber diet are more acceptable in the public's mind than the risk posed by Alar. For one thing, there is no "villain" — no one to blame. Second, food choices are voluntary, not forced, so that people can, quite literally, "pick their own poison."

Third, the issue of chemicals in food has been transformed into a "moral" issue. It is no longer a simple matter of harmful versus innocuous, but of good versus evil. Things "natural" are persistently viewed as "good," whereas chemicals added to foods are seen as "bad" — this despite the fact that, taken together, natural carcinogens overwhelm synthetic ones in their harmful effects.

Sandman emphasizes that outrage factors are not "distortions in the public's perception of risk [but rather] intrinsic parts of what we mean by risk," and must be considered in forming policy about risk management. He contends that when a risk manager continues to ignore these factors, and continues to be surprised by the public's response of outrage, "It is worth asking just whose behavior is irrational."

About the Author

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