British American Tobacco has published what it calls the first practical guide to the allergy-safe use of ingredients, such as flavourings, in e-liquids.
In a press note issued yesterday, the company said that, as with the use of many flavouring or fragrance-containing consumer products, ‘vaping’ e-liquid had the potential for causing an allergic reaction.
‘An allergic reaction is an overreaction by the body’s immune system to compounds that a person is ‘allergic’ to,’ the press note said. ‘Even if a compound has the potential to cause such a reaction (i.e. it is an allergen), that doesn’t mean it will. Whether an allergic reaction is likely, will depend on the person’s immune system and the amount of the compound used in a product.’
However, some substances were more likely than were others to cause allergic reactions, said BAT.
Flavourings were an important part of the vaping experience and some flavourings were known allergens. But currently, there were no specific allergy-related regulatory restrictions under either the Tobacco Products Directive in Europe or regulations administered by the Food and Drug Administration in the US.
Researchers at BAT had therefore devised a practical approach to assessing and managing the allergy risk associated with e-liquid flavourings and other ingredients (Regulatory Pharmacology and Toxicology http://dx.doi.org/10.1016/j.yrtph.2017.04.003). The guide is said to be a follow-up to the company’s blueprint for the safe use of flavourings in e-cigs, which was published in Regulatory Pharmacology and Toxicology in 2015 (https://doi.org/10.1016/j.yrtph.2015.05.018).
The most common allergy was contact sensitization arising when, for example, nickel jewellery touched the skin. Much less common was respiratory allergy, or ‘chemical asthma’.
“Although respiratory allergy is much less common than skin allergy, the potential adverse effects are much more severe,” said Dr. Sandra Costigan, principal toxicologist at BAT. “Chronic inhalation of respiratory allergens can lead to symptoms ranging from mild breathing difficulties to fatal anaphylaxis.”
‘For skin allergens, the researchers propose a method for estimating the exposures to e-liquid ingredients and quantitatively assessing the risk,’ the press note said. ‘This has then allowed them to work out a concentration of an allergen that is not expected to cause allergy in the person vaping the e-liquid.
‘For skin allergens, putting this into practice is relatively straightforward, as an approach to prevent contact sensitization is well established: The stronger the allergen, the lower the supportable concentration in e-liquid.
‘Additionally, the researchers say any known allergen should be labelled as an ingredient if it is present at 0.1 percent concentration or higher, even if it is established that it can be used safely at a higher concentration. This will help those consumers who already know themselves to be sensitive to certain ingredients to make product choices.’
For respiratory allergens, the authors used a cocoa extract as a case study, because cocoa is used quite commonly in e-liquids. The case study showed the tolerable levels identified for the cocoa extract were not sufficiently high to allow it to perform as an effective flavouring in e-liquid. In the guide, the researchers discuss why this is likely to be an issue for other respiratory allergens as well. And they recommend that respiratory allergens are not used at all.
Furthermore, quoting the low occupational exposure guidelines related to respiratory allergens (aimed at protecting workers against respiratory allergy from unintended exposure to allergens in the workplace), the researchers said it was prudent to exclude all known respiratory sensitizers from e-liquids. As an additional safeguard, if natural extracts were used as flavourings and there was no specific data on whether those extracts were respiratory sensitizers or not, only protein-free versions should be used. This was because most respiratory allergens from natural extracts came from the protein parts.
Food allergens were yet another type of allergen and the researchers recommended the presence of any potential food allergens (that are not already excluded for being respiratory allergens) should be labelled.
‘No two people have the same immune response, which is why it is important to tell people about allergens in a product even if all your data says most people shouldn’t experience a problem,’ said Costigan.