Tobacco companies might be actively promoting ‘harm reduction’ cigarettes, that are made using complex filters or by genetically altering tobacco plants to reduce nicotine concentration, as less harmful substitutes. But, researchers differ. Stem cell scientists at the University of California, Riverside says “they are not necessarily safer than their conventional counterparts.”

Prue Talbot, the director of UC Riverside's Stem Cell Center and the research team leader, said “Our analyses show there is significant toxicity in harm reduction products, and our data show that reduction of carcinogens in harm reduction mainstream smoke does not necessarily reduce the toxicity of unfiltered side stream smoke.”

As embryonic stem cells provide the best model currently available for evaluating the effects of environmental toxicants, researchers developed model young embryos to measure and compare toxic levels of traditional and side stream smoke from both conventional and harm reduction cigarette brands.

They examined the following harm-reduction cigarette brands: Marlboro Lights, Advance Premium Lights, and Quest. The team used Marlboro Red cigarettes to represent conventional brands.

After careful analysis, the research team concluded that “side stream smoke was consistently more potent to the embryonic stem cells than mainstream smoke, regardless of the brand.”

Tablot suggested that this valuable piece of information should be “taken into account when establishing policies regarding the sale, advertising, and use of harm reduction products.

Detailed results of the study will appear in the November issue of Toxicological Sciences.