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. 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.
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. 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. 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.