British researchers who have completed two new industry-sponsored studies on the possible toxic effects of smoking clove cigarettes conclude that clove cigarette smoke is no more harmful to laboratory rats than conventional cigarette smoke.
Representatives of the clove cigarette industry view the latest unpublished findings as further evidence vindicating clove cigarettes, or kreteks , the pungent-smelling Indonesian imports that have been criticized over the past 18 months as a health threat and as the alleged cause of the 1984 death of an Orange County teen-ager.
Largest U.S. Market
Several doctors and scientists familiar with clove cigarettes, however, remain convinced that the imports, which contain 60% tobacco and 40% ground cloves, are potentially more harmful to humans than regular cigarettes. Southern California is the largest U.S. market for clove cigarettes, accounting for more than a third of all such sales.
A 14-day inhalation study conducted by the Department of Inhalation Toxicology at the Huntingdon Research Centre in Huntingdon, England, showed that rats that had been exposed to clove cigarette smoke experienced "no significant toxicity or pathology" compared to rats exposed to conventional cigarette smoke.
Indeed, the researchers conclude in a written summary that "within this study, there was less evidence of smoke toxicity in the rats exposed to kretek smoke. It is probable that this result is due, at least in part, to the lower tobacco content of the kretek cigarettes. . . ."
The new findings are in agreement with an earlier one-day inhalation study conducted by the British research center and with the results of a separate short-term inhalation study conducted by the American Health Foundation in Valhalla, N.Y., a nonprofit independent research foundation funded primarily through the National Institutes of Health.
The British research center also conducted a eugenol inhalation study--said to be the first of its kind--in which eugenol, the major component of cloves, was inhaled by laboratory rats in aerosol form (Eugenol is used as a mild dental anesthetic and critics of clove cigarettes believe the substance numbs smokers' throats.)
In the study, researchers found that only temporary, readily reversible signs of toxicity were noted, including irregular breathing, weight loss and reduced food and water intake. But, according to the researchers, there were no deaths and no evidence of blood in the animals' respiratory tracts, and the rats were normal in all respects within 48 hours.
The results of the eugenol inhalation study differ sharply from those of an American Health Foundation study in which eugenol was administered directly into the lungs of laboratory hamsters.
In the American Health Foundation study, laboratory animals displayed symptoms similar to those in 12 cases of severe illness believed to be possibly associated with smoking clove cigarettes and reported to the Centers for Disease Control in Atlanta in 1985. Symptoms reported to the CDC included blood- or fluid-filled lungs, a constriction of the air passageways and coughing up blood.
The findings of the as-yet-unpublished British studies were released by the Specialty Tobacco Council, an organization representing the major manufacturers and importers of clove cigarettes in the United States.
The British research was funded by two of the council's members, P. T. Djarum and House of Sampoerna. The two Indonesian firms are the largest manufacturers of clove cigarettes, but industry representatives say the research laboratory did not know who commissioned the study.
"We now have three clove cigarette vs. ordinary cigarette comparison inhalation studies--two done by the Huntingdon Research Centre and one done by the American Health Foundation--and they all confirm the fact that no one can point to clove cigarettes as creating a problem that might not otherwise be associated, if in fact it is associated, with regular cigarettes," said G. A. Avram, executive director of the Specialty Tobacco Council.
Avram does not anticipate members of the Specialty Tobacco Council sponsoring any further studies.
Ball Is 'in Their Court'
"We think that if any more studies are needed, the critics ought to do something," Avram said. "As far as we're concerned we have accepted the ball that has been knocked on our side of the court and we feel like it's been hit back to the other side. I think it's now up to them to come up with some proof to back up any claims that they make."
Reaction to the results of the unpublished British studies is mixed.
Dr. Tee L. Guidotti, professor of occupational medicine in the University of Alberta faculty of medicine in Edmonton, Canada, who has studied clove cigarette toxicity, said the British studies "are not bad for what they do, but they don't ask the essential questions."