Home ENGLISH MAGAZINE E-cigs: those "fruity" liquids are not so harmless after all

E-cigs: those “fruity” liquids are not so harmless after all

E-cigarettes, popular battery-powered devices that simulate the act of smoking a traditional cigarette, dispense a vapor derived from liquid chemicals in a refillable cartridge. The refills typically contain propylene glycol, nicotine and often flavorings. Propylene glycol, a colorless, odorless food additive, s found in numerous processed food and beverages; it is also used as a solvent in a number pharmaceuticals. E-cigarette devices and refills are not well regulated, and the long-term health effects of e-cigarette use are not widely known. Nevertheless, flavoring and additive ingredients in e-cigarettes may increase inflammation and impair lung function, according to new research. The study, published ahead of print in the American Journal of Physiology–Lung Cellular and Molecular Physiology, also found that short-term exposure to e-cigarettes was enough to cause lung inflammation similar or worse than that seen in traditional cigarette use. Researchers studied several groups of mice that received whole-body exposure to varying chemical combinations four times each day. Each exposure session was separated by 30-minute smoke-free intervals.

  • One group was exposed to cigarette smoke (“cigarette”);
  • One group was exposed to e-cigarette vapor containing propylene glycol and vegetable glycerol, an odorless liquid derived from plant oils (“propylene”);
  • One group was exposed to e-cigarette vapor containing propylene glycol and nicotine (“propylene + nicotine”) and
  • One group was exposed to e-cigarette vapor containing propylene glycol, nicotine and tobacco flavoring (“flavoring”).

The cigarette and e-cigarette groups were compared with a control group that was exposed to medical-grade air. Some of the animals in each group were exposed to short-term cigarette smoke or e-cigarette vapor (three days), while others were exposed for a longer term (four weeks). The research team found an increase in markers of inflammation, mucus production and altered lung function in the propylene, propylene + nicotine and flavoring groups after three days. However, the propylene group showed fewer negative effects with long-term exposure, suggesting the additive alone elicits only a temporary irritation that eventually subsides with continued use.

In addition, two cytokine proteins became elevated on in the flavoring group, suggesting that some of the many flavoring components on the market may not be safe for even short-term use. The condition of the e-cigarette groups in comparison with the cigarette group surprised the researchers. The level of oxidative stress in the flavoring group was equal to or higher than that of the cigarette group. However, respiratory mechanics were adversely affected only in mice exposed to cigarette smoke and not to e-cigarette vapor after prolonged treatment. This because flavoring aldehydes, propylene glycol and nicotine are less “toxic” to oxidized hydrocarbons, tar and the other 700 components of tobacco combustion. Nonetheless, aldehydes promptly react with proteins creating adducts (AGE-like) that might impair extensibility of lung skeletal proteins (e.g. elastine). In addition they may generate oxidative stress through the same mechanism and contribute to the tissue inflammation. The observed detrimental effects in the lung upon e-cigarette vapor exposure in animal models, highlight the need for further investigation of safety and toxicity of these rapidly expanding devices worldwide. Particular concern is toward adolescents that seem to prefer vaping over the traditional “smoking”.

  • edited by Dr. Gianfrancesco Cormaci, PhD, specialist in Clinical Biochemistry.

Scientific references

Wang JB, Olgin JE et al. PLoS One. 2018; 13(7):e0198681.

Caruso M, Li Volti G et al., Polosa R. Front Physiol. 2018; 9:1240. 

Muthumalage T et al., Rahman I. Front Physiol. 2017; 8:1130.

Javed F et al., Rahman I. Oral Dis. 2017 Nov;23(8):1052-1057.

Clapp PW et al. AJP Lung Cell Mol Physiol. 2017; 313:L278-92.

Dott. Gianfrancesco Cormaci
- Laurea in Medicina e Chirurgia nel 1998 (MD Degree in 1998) - Specialista in Biochimica Clinica nel 2002 (Clinical Biochemistry residency in 2002) - Dottorato in Neurobiologia nel 2006 (Neurobiology PhD in 2006) - Ha soggiornato negli Stati Uniti, Baltimora (MD) come ricercatore alle dipendenze del National Institute on Drug Abuse (NIDA/NIH) e poi alla Johns Hopkins University, dal 2004 al 2008. - Dal 2009 si occupa di Medicina personalizzata. - Guardia medica presso strutture private dal 2010 - Detentore di un brevetto sulla preparazione di prodotti gluten-free a partire da regolare farina di frumento immunologicamente neutralizzata (owner of a patent concerning the production of bakery gluten-free products, starting from regular wheat flour). - Responsabile del reparto Ricerca e Sviluppo per la società CoFood s.r.l. (leader of the R&D for the partnership CoFood s.r.l.) - Autore di un libro riguardante la salute e l'alimentazione, con approfondimenti su come questa condizioni tutti i sistemi corporei. - Autore di articoli su informazione medica, salute e benessere sui siti web salutesicilia.com e medicomunicare.it

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