Hazards at the Plate? Children and Food Safety Risk

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International Food Information Council Foundation

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Whether selecting a family car, deciding where to live or just choosing what to watch on TV, parents everywhere tend to share the same credo- nothing's too good for my kids.

Ensuring the safety and wholesomeness of foods for infants and children is no exception.

But public confidence in food safety for the nation's 63 million youngsters is unsteady. As one recent example, the Alar controversy panicked many parents into pouring out apple juice and school officials into banning the sale of apples from school-lunch programs.

And according to a recent poll by the Center for Produce Quality, 72 percent of Americans believe pesticide regulations do not sufficiently account for children's health risks.

In the wake of such concerns, child health advocates, environmentalists, the food industry and others are working with federal authorities to bring the best scientific evaluation possible to pesticides and other food-related risks to children.

Children Are Not Small Adults

Children cannot be viewed simply as miniature adults, said pediatricians, toxicologists, and regulators gathered last fall at a risk assessment symposium on similarities and differences between children and adults. Sponsored by the Environmental Protection Agency and the International Life Sciences Institute, the symposium evaluated biological, social and environmental factors related to children that can affect their risk from foods, pesticide residues or other substances.

Most notably, children's dietary patterns differ from adults in both quantity and types of foods consumed. In relation to body weight, children eat more food than adults to meet their demands for rapid growth. This is particularly true among preschoolers.

Also, children's consumption of certain types of foods such as fruits and fruit juices can be quite different from adults. In addition to these basic dietary differences, variables such as nutritional status, socioeconomic level, culture and geographic location can profoundly affect a child's health risk from certain substances.

While not exposed to the same occupational hazards as adults, children's home, school and play surroundings can influence their health risk. J. Michael Davis, Ph.D., a health scientist with the EPA Office of Health and Environmental Assessment, has noted that children are generally exposed to much higher levels of lead through airborne sources, household dust and soil, lead paint, and pipes, in addition to diet. Thumbsucking and other typical hand-to-mouth behaviors may account for as much as 80 percent of all children's lead-related exposures.

Several biological factors in children can make them either more or less sensitive than adults to various substances. Children have higher rates of breathing and blood flow, and many of their organ cells multiply at a faster rate through normal growth. Also, the rate at which certain drugs or chemicals pass through cell membranes in children varies from adults, influencing potential toxicity.

In addition, children's metabolism of certain chemicals may be more or less efficient than adults. Young children are known to have a greater tolerance than adults to acetaminophen, the most widely used over-the- counter drug for pain and fever in the United States. Some scientists believe this phenomenon may be due to children's greater capacity to safely eliminate the drug by non-toxic metabolic pathways.

The immature immune systems of infants and children can also place them at greater risk from infection, including microbiological contamination of foods. Health officials are stepping up public education efforts to reduce incidence of foodborne illness in children and other groups such as the elderly that may have vulnerable immune systems.

Implications for Risk Assessment

What do such differences between children and adults imply in terms of health risk assessment? Few generalizations apply.

According to symposium co-chairman Philip Guzelian, M.D., of the Medical College of Virginia, children may be more, less than or similarly sensitive as adults to adverse health effects from certain substances.

"The complexity of variables makes it important to evaluate children's health risk on a substance by substance basis," said Guzelian. "Although children are physically more vulnerable and diminutive in stature, it is incorrect to assume that they are always more sensitive than adults to potentially harmful effects of substances."

Food Protection for Children

In determining the safety of a proposed pesticide or food additive, EPA and FDA consider the unique characteristics and sensitivities of a wide variety of groups, including infants and children.

To help ensure that each sensitive subgroup is adequately protected, regulators use data from the most sensitive and relevant animal species and, in certain cases, human studies. Ultimately, the evaluation of a substance integrates the analyses of both its potential toxicity to a subpopulation, as well as that group's exposure to the substance through diet.

FDA and EPA require that manufacturers provide chemistry studies of a proposed food additive or pesticide intended for use in food crops, and toxicity data from studies in young animals through adulthood. The chemical's potential to cause birth defects, reproductive effects and adverse effects on the nervous system and other organs are evaluated carefully.

Multigeneration animal studies help determine a substance's reproductive effects when administered to the mother before conception, while the fetus is in the womb, and during lactation.

If such experimental or hypothetical evidence suggests that children or other groups may be more sensitive to the potential effects of a pesticide or food additive, the agencies require additional safety studies in animals or humans.

Both agencies then use these data to help determine safe levels. These levels are known as a reference dose (RfD) for pesticides and an acceptable daily intake (ADI) level for food additives. The RfD or ADI is an estimate of the amount of a substance that humans can be exposed to safely every day over a lifetime without adverse effects. Scientists apply a large safety factor, usually 100-fold or more, to help adjust for extrapolations from animal data to humans and for any unique sensitivities of various groups such as infants and children.

Calculating Dietary Exposures

To estimate potential exposure to pesticide residues, EPA uses food consumption data gathered as part of the U.S. Department of Agriculture's Nationwide Food Consumption Survey. The survey profiles the types and amounts of food consumed over several days for all Americans, as well as subgroups.

All foods are analyzed by their separate ingredients using EPA standard "recipe files" for 300 different foods. For example, the amount of wheat flour, tomato, cheese, oregano, and other ingredients are estimated for a serving of pizza. All foods in a person's daily diet are analyzed, and the amounts of similar food components are added (e.g., total amount of wheat flour consumed from various foods in a day). These data, in turn, are used along with information on pesticide residues on individual foods to estimate overall dietary exposure to a pesticide.

EPA also has developed a special data base known as the Dietary Risk Evaluation System (DRES). This system allows the agency to refine its exposure estimates for pesticides in the diets of infants, children and other potentially sensitive subgroups. The DRES system provides information on food consumption for more than 300 food commodities for 22 different subpopulations.

According to William Farland, Ph.D., director of EPA's Office of Health and Environment Assessment, "If the DRES analysis indicates that exposure to a subgroup is so high that adverse effects may occur, then EPA will not approve a tolerance even if the estimated risks to the overall population are acceptable."

One case in which EPA did not approve a tolerance because of specific dietary concerns for infants and children involved the pesticide pydrin in 1985. New uses of the chemical on alfalfa and sorghum were requested to be allowed. However, EPA determined that the potential risks to children from secondary residues in milk from cows eating such grains were unacceptable, and the agency denied the request.

When it comes to food additives, FDA requires the manufacturer or sponsor of a food additive petition to provide an estimate of the anticipated consumption of the substance, based on the food categories in which its use is proposed. Such data include frequency of consumption and amounts consumed by all age groups, based on a nationally representative sample of Americans.

What About Cancer?

Because cancer is generally observed years or decades after exposure to a substance, EPA sets limits on dietary cancer risk based on a lifetime of exposure. Lifetime exposure for a particular pesticide is estimated by summing up the average food consumption estimates for the overall U.S. population.

Under the 1958 Delaney amendment to the Federal Food, Drug and Cosmetic Act, FDA is prohibited from approving the use of any food additive if it is found to cause cancer in any animal species or man, at any dose level. Given the increased sophistication of analytical techniques over the past 30 years, the appropriateness of Delaney's zero-risk standard has been widely debated. Current technology is capable of detecting minute traces of contaminants that theoretically provide the basis for banning a food additive, regardless of the insignificance of its public health risk.

EPA , however, is permitted by law to apply a "negligible-risk" standard for pesticides found to cause cancer in animals. Using conservative risk assumptions, EPA estimates an exposure that gives a theoretical cancer risk of no greater than one in a million over the average person's 70-year lifetime. In setting an acceptable risk level, EPA takes into account that somewhat greater exposure to a substance will occur at different points in life than others.

The "one-in-a-million" level of risk does not mean that there will be one actual case of cancer in a million people. The "one-in-a-million" estimate is virtually the highest level of risk EPA expects might occur. The actual risk may be as low as zero.

Next Steps

At the request of EPA, the National Academy of Sciences is completing a study of the health risks of pesticides in the diets of infants and children. The study is expected to be released later this year.

EPA officials will review results from this study in their efforts to continually evaluate and improve the regulatory approach to protecting sensitive subpopulations. Currently, the agency is working on revised guidelines for developmental toxicity testing of various pesticides, and is studying the feasibility of collecting supplemental food consumption data for certain population subgroups with small sample sizes.

EPA also is developing a policy statement on the use of subgroup exposure estimates in risk assessment. In future Federal Register notices on pesticides and other chemicals, the agency will discuss its evaluation of the risk to the most sensitive population subgroups, including differences in risk levels for infants and children. In the meantime, parents or professionals should not be reluctant to promote consumption of vegetables, fruits or fruit juices by infants and children. The Diet and Health report issued by NAS in 1989 concluded that there is no evidence that pesticides or natural toxicants in food contribute significantly to cancer risk in humans.

The American Academy of Pediatrics echoed this point by stating, "The risks to children over their lifetimes of experiencing the major chronic diseases associated with the typical American diet far exceed the theoretical risks associated with pesticide residues... a diet rich in fruits and vegetables is the most healthful diet that children can consume."

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Reprinted from the International Food Information Council Foundation