Tobacco Smoke Flavoring Contains Hazardous Chemicals

Scientists have new data that toxic flavoring chemicals found in cigarettes are reaching smokers through cigarette smoke and may pose health hazards of their own. The finding is reported in the April issue of the Journal of Agricultural and Food Chemistry, published by the American Chemical Society, the world’s largest scientific society.

The flavoring chemicals, known as alkenylbenzenes, are found in tobacco additives used to enhance the taste of cigarette smoke. Until now, no one knew how much of the compounds entered cigarette smoke, according to lead author David Ashley, Ph.D., at the U.S. Centers for Disease Control and Prevention in Atlanta.

The researchers used a new detection method to analyze the cigarette smoke of eight U.S. brands. Previously, no method existed to easily and accurately measure the flavoring compounds in a single cigarette.

Long-term health effects from inhaling alkenylbenzenes directly or by second-hand smoke are unknown in humans, though earlier research associated them with cancer and lung damage in laboratory animals.

The National Academy of Sciences deems flavorings containing alkenylbenzenes safe for human foods. The additives, when eaten by humans, are thought to be safely eliminated by the liver. Cigarette smoke, however, delivers the chemicals to the lungs, where they spread through the body before the liver can screen them.

In the study, smoke from all types of cigarette — filtered, unfiltered and menthol — was tested for flavoring chemicals. Brand names were not released. Varying levels of five alkenylbenzenes were found in each, according to the researchers. In previous CDC research, researchers found one or more flavoring compounds in the tobacco of 42 of the 68 U.S. cigarette brands they examined.

One of the chemicals was found at levels up to four micrograms per gram of tobacco. Higher levels were found in the smoke when ventilation holes in the cigarette’s filter were blocked.

In animals, exposure to the chemicals can cause cancer and lung disease. In rodents, for example, animals inhaling one flavoring compound — eugenol — show far more serious adverse health effects than animals eating it, according to previous research.