LIQUIDS used in electronic cigarettes contain potentially harmful chemicals, such as trans-cinnamaldehyde, menthol, and benzal, among others – but for a majority of them, there is no information about the adverse health effects available, as per the latest research released by Medical Journal of Australia.
Associate Professor Alexander Larcombe conducted the study from the Telethon Kids Institute and the Wal-Yan Respiratory Research Centre and Prof. Ben Mullins and Dr. Sebastien Allard of Curtin University. He was an expansion of research conducted previously. Researchers studied a more extensive selection that included 65 “e-liquids” before and after an acceleration of aging which mimicked the effects of smoking. The e-liquids tested from Australian suppliers were labeled “nicotine-free.”
“Nicotine was found in trace amounts in six fresh e-liquids (maximum, 3.25 mg/L) but not in aged e-liquids,” Larcombe and coworkers published.
“In our previous study in the past, six of the 10 e-liquids had nicotine (maximum 2990 mg/L). The results of our more recent samples might suggest cleaner manufacturing processes or the nicotine was present in nicotine salts, rather than freebase nicotine,” they wrote.
“Propylene glycol” and Glycerol are the principal components in the proportions of each E-liquid. The propylene glycol/glycerol ratio is not stated for the three liquids. Many e-liquids were advertised with a percentage of 30% propylene-glycol and 30 percent glycerol. However, the actual amount was less than 10 percent of the amount stated on the label for only 11. (propylene glycol) or 21 (glycerol) of the liquids.
“Benzyl alcohol is a flavor enhancer, and the solvent was detected in 42 of 65 e-liquids and 32 aged e-liquids at levels up to 1687 mg/L. The alcohol Benzyl … can be an ingredient that causes dermal sensitization and skin allergen, which can cause severe reactions in specific individuals.
“Benzaldehyde is added to E-liquids to enhance the almond flavor and is detected in fresh 60 and 61-aged liquids at levels ranging between 11.4 Ug/L to 17.3 mg/L. Benzaldehyde blocks Microsomal Cytochrome P450 2A6 (CYP2A6)20, which increases nicotine exposure to the system and nicotine levels in smokers’ blood samples. It also decreases the process of phagocytosis (a method used to clear cells and pathogens) and is an irritant for inhalation. The benzaldehyde compound can also react with propylene glycol found in E-liquids, creating aldehyde propylene glycol acetals that stimulate airway irritant receptors.
Other chemicals that flavoured cigarettes are commonly found included menthol (“enhances the nicotine’s addictive properties and blocks nicotine metabolism”) and the ethyl maltol (“effects that are induced by heating it and breathing in its vapors are unknown, however it enhances the formation of free radicals in the e-cigarette’s aerosols; free radicals cause oxidative stress which impacts cell survival and growth, as well as inflammation; reacts with copper and iron (potentially found in e-liquids as coil residues) to create harmful hydroxypyranone compounds”) trans-cinnamaldehyde (“impairs the function of innate immune cells inside the lung and suppresses the bronchial airway epithelial cells mitochondrial and ciliary motility and blocks microsomal CYP2A6 and impairs neutrophil, macrophage, as well as natural killer cells function, and decreases the oxidative burst when inhaled heated”) as well as vanillin ethyl (“reduces the oxidative burst rate and blocks in vitro formation of free radicals”).
“We found that a range of harmful chemicals are present, and that the heating/cooling/ageing process can affect e-liquid chemical composition,” Larcombe and colleagues concluded.
“We recognize that the compositional chemical of electronic liquids may not be completely comparable to the aerosol that is inhaled by users of e-cigarettes. However, our findings that all e-liquids examined contained at least one of the substances that could be harmful to health is a compelling reason to further research.”
