Blame Outdated Law — Not Science — For The Latest Artificial Flavor Cancer Scare
Last week, the Food and Drug Administration announced that it will no longer allow seven artificial flavors commonly found in baked goods, ice cream and other foods.
The change sprang from a petition arguing that since megadoses of six ingredients — benzophenone, ethyl acrylate, methyl eugenol, myrcene, pulegone and pyridine — cause cancer in laboratory animals, their use as food additives breaks federal law. The seventh ingredient, styrene, was removed because manufacturers no longer use it.
Yet in its next breath, the FDA issued a major caveat: All the banned ingredients “are unlikely to pose a potential or significant carcinogenic risk for humans at the levels that these synthetic flavoring substances are used in foods.” Translation? We think they’re safe, but the law requires us to ban them anyway.
Only in D.C. will you find contradictions on such a monumental scale.
Indeed, both of the FDA’s premises are true. In a laboratory setting, rats and mice developed more tumors after consuming quantities of these artificial flavors that would make even the most frequent snacker’s head spin. Although some doses reached the human equivalent of consuming as much artificial flavor as you’d find in 366,000 cookies, cancer arose nonetheless.
At the same time, evidence of cancer at doses analogous to actual human consumption simply doesn’t exist. Human epidemiological studies, where researchers track what participants have eaten over weeks or years, have also come up empty-handed.
The source of the FDA’s conundrum can be dated back to a law called the “Delaney Clause,” which was added to the Federal Food, Drug, and Cosmetic Act in 1958. It prohibits the agency from approving food additives that have been found to cause cancer in laboratory animals, though it does so with no regard to the probability, or risk, that a human would develop the same cancer. The Delaney Clause is a relic of a bygone era of understanding, passed even before professional toxicologists had established an academic journal devoted to the field.
Today, chemical toxicity testing isn’t conducted under such simplistic measures as “cancer bad, no cancer good.” As the National Academy of Sciences asserted in its 1994 assessment of the U.S. Environmental Protection Agency’s (EPA) toxicology and risk assessment practices, “It is not usually known how similar the toxic responses in the test animals are to those in humans, and scientists do not have indisputable ways to measure or predict cancer risks associated with small exposures.” Just because a substance is capable of causing cancer at high doses in animals doesn’t mean it carries the same risk at low doses in humans.
But what kind of risk are we talking about when it comes to artificial flavors? According to the data, it’s very, very small.
Scientists believe the majority of the banned flavorings cause cancer in ways that simply aren’t possible in humans. Benzophenone, for example, likely produces kidney tumors in male rats when the animal is also sick with an age-related disease called chronic progressive nephropathy. Humans can’t get this disease, so scientists don’t believe we have the correct biological pathway, called a “mode of action”, that turns benzophenone from a flavor enhancer to a tumor generator.
For methyl eugenol, the only of these artificial flavors with a mode of action that does exist in humans, FDA scientists believe the extremely high doses — 220,000 to 890,000 times higher than the upper estimate of human dietary exposure — were responsible for overloading the animals’ normal functions.
High-dose studies are important for discovering a chemical’s worst-case scenario so that researchers know which small changes to look for once they conduct lower dose studies. Unfortunately, the implications of the initial search are exaggerated all too often by those looking for a quick fix for one of society’s most deadly diseases.
FDA scientists believe the extremely high doses — 220,000 to 890,000 times higher than the upper estimate of human dietary exposure — were responsible for overloading the animals’ normal functions.
At a surface level, the Delaney Clause appears to be a simple provision: Don’t allow ingredients in our foods if they cause cancer in the laboratory. But it’s this simplistic thinking and the ensuing overreliance on animal testing that puts pharmacologists and toxicologists in a precarious situation when drugs that perform flawlessly in animal studies fail in clinical trials, or when chemicals turn out to be more or less toxic to humans than previously anticipated.
It seems our legal understanding of chemical safety could use a good overhaul.
In fact, as early as 2008, five federal agencies — the National Institutes of Health (NIH), National Toxicology Program (NTP), Food and Drug Administration (FDA), and Environmental Protection Agency (EPA) — initiated a joint effort to replace animal testing with more accurate, less expensive technologies. The Toxicology in the 21st Century program, or Tox21, uses robots to conduct high-speed, iterative screening of suspected toxins using human and animal tissues, cells, and molecular targets instead of rats and mice. It allows these exploratory studies to be conducted under conditions and in quantities that produce far more useful results than traditional animal toxicity studies.
Dr. Ruili Huang, one of the NIH researchers heading these efforts, lauds the program’s efficiency in screening chemicals of concern. “We can test all the chemicals at 15 different concentrations each and in three independent experiment runs in one week. With animal testing, this would take years.”
It’s no secret that technology has evolved in the past six decades, and chemical toxicity testing is no exception. Federal research institutions are already a decade into their foray with Tox21. It’s time for federal law to reflect these advancements in understanding as well.
A version of this story first appeared in The Daily Caller.