Suspected Carcinogen Speeds Through People’s Bodies

A commonly used but potentially carcinogenic flavoring compound stays in people’s bodies only briefly, according to a new study, but scientists aren’t ready to rule out health risks from the chemical.

Methyleugenol is an essential oil in foods and spices ranging from bananas to basil. In its natural form or a synthetic version, the agent flavors a seemingly endless list of foods: candy, cookies, bubblegum, pumpkin pie, puddings, ice cream, cola drinks, apple butter, chutney, pâtés and terrines, anise biscotti, French toast, mincemeat, sweet chili sauce, puddings, ketchup, nutmeg, and gingerbread. Alone, the compound has a bitter, burnt taste and smells like clovers and carnations.

Past research has shown that the flavoring causes cancer of the liver, stomach, kidneys, and connective tissues in mice and rats. No study has proved a carcinogenic effect in people, but the biennial Report on Carcinogens released by the federal government’s National Toxicology Program (NTP) in 2002, for the first time listed methyleugenol as “reasonably anticipated to be a human carcinogen.” Also, 98 percent of 206 adults tested for methyleugenol while participating in the third National Health and Nutrition Examination Survey (NHANES III) from 1988 to 1994 had detectable concentrations of the chemical in their blood.

In the current study, scientists at NTP, the Centers for Disease Control and Prevention, the University of Texas at Dallas, and Duke University tested how people’s bodies handle and react to methyleugenol over a few hours. The team asked each of nine volunteers to fast overnight and then eat 12 gingersnaps that were high in methyleugenol.

Blood samples taken before the volunteers ate the cookies revealed an average blood concentration of 16.2 picograms of methyleugenol per gram of blood serum. The concentration peaked at 53.9 pg/g 15 minutes after the volunteers ate the cookies and, within 2 hours, returned nearly to the fasting concentration. The results are in the online version of Environmental Health Perspectives.

As in mice and rats, the period of time methyleugenol stayed in people’s bodies was brief. The scientists presume that methyleugenol was quickly absorbed in the gut and metabolized into products that were released in the study participants’ urine. The elimination rate of methyleugenol appears to be much faster than the years it typically takes people to clear dioxins. For example, it takes the human body 7 to 11 years to eliminate half the amount it holds of 2,3,7,8-tetrachlorodibenzo(p)dioxin, a dioxin from agent orange.

Is there a risk of getting cancer from eating gingersnaps? “Hard to say,” says Christopher Portier, a coauthor of the new report and an NTP associate director. The lowest dose of methyleugenol given to rodents in cancer tests is 10,000 times what the volunteers got by eating the cookies.

Nevertheless, the researchers made an interesting observation when they compared their volunteers’ methyleugenol blood concentrations with those from people in the NHANES III study. “Much to my surprise . . . there are some people who are walking around with markedly higher levels of methyleugenol than what we found at 15 minutes with our people [eating methyleugenol-rich gingersnaps],” says Arnold Schecter, an environmental health scientist at the University of Texas School of Public Health at Dallas. The comparison may not be perfect because NHANES III volunteers weren’t fasting, adds Portier. However, he says finding unusually high methyleugenol levels in some people suggests that there are many sources of methyleugenol in the environment.

Aside from ingesting methyleugenol, people are exposed to the compound by inhalation and skin contact. Perfumes, toiletries, sunscreens, and cigarettes contain methyleugenol. It’s even used in laboratories as an anesthetic for rodents.