The media frequently report claims by nonprofit consumer groups about alleged health hazards in our food supply and our environment. Often these claims are coupled with suggestions for specific actions to reduce the purported risk of disease or premature death by avoiding or reducing exposure to the allegedly harmful substance.
The American Council on Science and Health (ACSH), a consumer education group directed and advised by over 300 leading scientists and physicians, has reviewed many such reports and claims. After carefully considering the scientific evidence, ACSH concludes that it would be in the best interest of the American consumer if the media treated such reports with a greater degree of skepticism than is currently employed.
Supposedly, the public claims and warnings that these activist groups make are based on scientific evidence. But in general, there is no independent peer review of their claims or recommendations. The groups publish the reports themselves, often via press release or paid advertisements. Often, the claims are extrapolations from small studies or animal studies, and lack strong supporting evidence. This is not the way mainstream science works.
Scientists working in academic institutions, for example, submit their work to journals that then have the papers reviewed by other scientists with appropriate expertise. Such papers must clearly delineate the methods used to obtain the published results, as well as the statistics used to analyze them. Both will be examined and criticized by reviewers. If a body of work does not pass muster, it will either be rejected for publication, or the author(s) will be required to revise it, and perhaps supply additional information, before it is published. A scientific paper of high quality may be revised and reviewed more than once before publication. While this process isn’t always perfect, it is the best procedure we have to insure that the scientific information presented to the public is based on valid data that are analyzed in an appropriate manner. Its value has been shown decisively over decades of experience.
Additionally, reputable scientists understand that a single report, wherever it may be published, is not “proof” of a theory or hypothesis. Experiments or observations must be replicated by independent research in order to be considered valid. Often, however, advocacy groups don’t wait for confirmation before sounding an alarm that may be based on poorly designed or single studies, or on studies that are performed only on laboratory animals. When disapproving of a product or chemical, they may cite anecdotal, unsupported reports of ill effects, neglecting to validate the data. Or, they may cite data selectively, choosing only those data that support the point(s) they wish to make.
Another feature of many of these groups’ alarms is direct extrapolation of data from high-dose animal tests to predict disease risk in humans. The assumption is that any chemical, food, or product that causes harm to animals in high-dose testing situations must also harm humans, even if the typical human exposure is orders of magnitude less than those used in the animal tests.
While animal testing is certainly a valid and necessary means of examining the possibility that a chemical might be harmful to humans, a finding of harm in such tests does not automatically mean that humans exposed at much lower doses will also be harmed. More information, such as typical or expected toxicity and human exposure, must also be factored into any assessment of risk to humans. Further, the possibility that any chemical or compound is harmful to humans is strengthened if it is found to be harmful to more than one species of experimental animal. Thus, finding that a compound is toxic or carcinogenic at high dose to laboratory rats, but not to mice or rabbits, would weaken the argument that humans might be affected (for more information on animal testing, see the ACSH publications “Of Mice and Mandates” at http://www.acsh.org/publications/pubID.153/pub_detail.asp and America’s War on “Carcinogens” at http://www.acsh.org/publications/pubID.992/pub_detail.asp ).
Yet, such scientific facts are only rarely mentioned, and then as caveats at the end of a story.
Parents of babies and young children often are the group most concerned about potential health risks stemming from foods or environmental exposures. A common attention-grabbing ploy is to paint a particular risk as especially harmful to babies or young children. Thus, the NRDC promotes their study of children’s exposure to diesel exhaust, and the PCRM inveighs against the drinking of milk by children. Public health policy, however, should be based on competent risk assessments, not hyperbole.
In this report, ACSH reviews claims by four self-styled consumer groups and evaluates the scientific veracity of some of their statements. Further, the report proposes some guidelines and follow-up questions for the media to use in assessing the scientific quality of health-related claims.
ACSH considers statements by the Center for Science in the Public Interest (CSPI), the Environmental Working Group (EWG), the Natural Resources Defense Council (NRDC), and the Physicians Committee for Responsible Medicine (PCRM) as examples of claims about health concerns that are not grounded in sound science yet have been widely covered by the media.
BELOW IS A TABLE OF CONTENTS FOR THE FULL REPORT, WHICH CAN BE ORDERED -- OR DOWNLOADED FOR FREE -- AT THE RIGHT MARGIN.
