A banned flavouring linked to cancer has been found in dangerous levels in e-cigarettes, experts have warned.
Scientists say the chemical — called pulegone — is contained in menthol and mint-flavoured vapes and smokeless tobacco products, The Sun reported.
The US Food and Drug Administration banned pulegone as a food additive last year because of its carcinogenic properties following pressure from consumer groups.
Yet the agency does not regulate the chemical’s presence in e-cigarettes, according to the new study from Duke University Medical Centre, published in the journal JAMA Internal Medicine today.
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Lead author Professor Sven-Eric Jordt said: “Our findings suggest that the FDA should implement measures to mitigate pulegone-related health risks before suggesting mint and menthol-flavoured e-cigarettes and smokeless tobacco products as alternatives for people who use combustible tobacco products.”
Dr Jordt and his research partner Sairam V. Jabba started looking into e-cigarette liquids after the US Centres for Disease Control and Prevention (CDC) published studies showing that they contain substantial amounts of the chemical.
CAUSE FOR CONCERN:
The two researchers analysed whether several top brands of regular menthol cigarettes, three e-cigarette brands and one smokeless tobacco brand contained enough pulegone to be a cause for concern.
They compared the CDC-reported amounts of pulegone with the levels at which exposure-related tumours were reported in animal studies.
Their analysis found the levels in the e-cigarettes and smokeless tobacco exceeded the thresholds of concern.
However, regular menthol cigarettes contained levels below the thresholds.
Dr Jordt added: “Our analysis suggests that users of mint and menthol-flavoured e-cigarettes and smokeless tobacco are exposed to pulegone levels higher than the FDA considers acceptable for intake in food and higher than in smokers of combustible menthol cigarettes.
“The tobacco industry has long known about the dangers of pulegone and has continuously tried to minimise its levels in menthol cigarette flavourings, so the levels are much lower in menthol cigarettes than in electronic cigarettes.”
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LIMITATIONS
E-cigarette manufacturers may be less familiar with the dangers and use cheaper ingredients to lower costs, the researchers said.
But experts warn this study has its limitations and its findings should be considered carefully.
Prof Paul Aveyard, professor of behavioural medicine at University of Oxford, notes that not all pulegone in e-liquids are absorbed during vaping.
“The study seems to have reported on the pulegone concentration in e-liquids, making the unjustified assumption that all the pulegone in the e-liquid is absorbed,” he said.
“We know, for example, that nearly all the nicotine in e-liquid is not absorbed either from cigarettes or from e-liquids, and it is likely that most pulegone is not absorbed, as most of the vapour from e-cigarettes is exhaled.”
Dr Lion Shahab, senior lecturer in epidemiology and public health at the University College London (UCL), added: “The study did not assess actual exposure in humans, which is important, because exposure is not simply a function of e-liquid constituents but also of the interaction between users and how they use e-cigarettes to warm up the e-liquid.
“Further, the data used to derive the likely exposure profile comes from a limited number of e-liquids assessed more than five years ago.
“It is therefore unclear if results apply to products used nowadays.”
The research has been published the day after New York State governor Andrew Cuomo banned all flavoured e-cigarettes from being sold.
He warned that flavours, including bubblegum and cotton candy, were leading young people to get hooked on nicotine.
This article originally appeared on The Sun and was reproduced with permission