It’s no secret that smoking e-cigarettes can lead to long-term health issues.
But scientists now say that some flavours of vapes could be far worse than others.
Researchers from McGill University in Canada found that berry-flavoured e-cigarettes cause more damage to your lung’s immune cells than other varieties.
During tests on mice, the researchers found that the sweet vape interfered with cells called alveolar macrophages and prevented them from clearing out bacteria.
The researchers say that this could lead to severe illness, respiratory distress, and even death.
However, the scientists found that mice exposed to flavourless or menthol vapes did not experience the same detrimental impacts.
This suggests that some chemicals used to flavour e-cigarettes could be more harmful to our lung health than others.
However, the researchers stress that multiple vape flavours – not just berry – are packed with chemicals that are linked to lung damage.
Researchers say that berry-flavoured vapes could be far more harmful than flavourless or menthol alternatives (stock image)
The study used the Razzy3Some berry flavour vape liquid. Vaping works by heating liquid in a small device so you can breathe it into your lungs. The liquid, called an e-liquid, typically contains nicotine, propylene glycol, vegetable glycerine and flavourings
Study co-author Ajitha Thanabalasuriar at McGill University told MailOnline: ‘From our study we see that the more complex flavours and additives you add to e-cigs the more bad outcomes on immunity.’
As vaping rates increase among young people, there is a growing body of research which suggests that using vapes can be harmful.
In addition to nicotine which can be detrimental to heart health, vapes contain numerous chemical additives and flavourings.
However, there has been little research into how specific flavourings alter the health impacts of e-cigarette use.
To investigate this connection, Dr Thanabalasuriar and her colleagues looked at how immune cells in mice were affected by different types of vape.
Mice were kept in a box for 10 days either containing either fresh air, berry-flavoured e-cigarette vapour (with the brand name ‘Razzy3Some’), or unflavoured e-cigarette vapour.
Berry was chosen as a representative flavour due to its popularity with many vape users
The researchers then stained the alveolar macrophages (AMs) so that they would show up on a microscope and looked to see if their behaviour had changed.
AMs live on the walls of our alveoli, the microscopic sacs in our lungs which allow gases to pass from the air into our bloodstream.
From menthol to vanilla custard and sour strawberry, there’s an estimated 40,000 vape flavours on the market today worldwide
Researchers tested how berry and unflavoured vapes affected the immune cells living in our alveoli (illustrated) by exposing mice to continuous e-cigarette vapour for 10 days
As the ‘crossroads’ between our internal organs and the outside world, they are a critical point for immunity.
To avoid infection, AMs patrol the surface of the alveoli acting as sentinels against incoming pathogens and pollutants.
In the control mice (who were not exposed to any vapes), analysis showed that the cells carried out their probing, squeezing, and patrolling behaviours as normal.
However, after 10 days of continuous exposure to berry-flavoured e-cigarettes, the researchers found that the AM’s mobility had significantly reduced.
Rather than probing for pathogens, squeezing through the gaps between alveoli, and patrolling the cell perimeter, the vape-affected cells largely remained stationary.
Surprisingly, when the researchers looked at AMs exposed to flavourless or menthol vapes, they found that these cells had almost no differences from the control group.
The macrophages continuously exposed to flavourless e-cigarettes for 10 days proved to be just as mobile as those in the clean air control group.
Dr Thanabalasuriar says: ‘The macrophages move around our airways vacuuming up debris and infections. Berry vapes but not flavourless hinders this movement.’
After 10 days the immune cells in the alveoli of mice exposed to berry-flavoured vapes (right) showed significantly less movement than those exposed to clean air (left)
This graph shows the movement of an alveoli immune cell after being exposed to air (left) and to vaping for three (middle) or 10 (right) days
The findings, published in PNAS, are a worry for human health because hindering AM movement limits their ability to clear out harmful bacteria.
Researchers then infected the trial mice with a bacteria called Pseudomonas aeruginosa, a pathogen which infects the alveoli and is common in smokers.
This bacteria poses no threat to healthy humans and mice which can easily fight back the infection.
However, mice who had been exposed to berry-flavoured vape showed significantly higher bacterial counts seven days after being exposed to the virus.
By reducing the ability of immune cells to clear the infection, vaping berry-flavoured e-cigarettes led to slightly higher mortality rates among the mice.
The researchers point out that, while this might not lead to deadly outcomes for humans, it could mean that vapers take longer to clear infections and need more antibiotics to recover.
Dr Thanabalasuriar says the more flavouring chemicals in a single vape flavour, the greater this effect is likely to be.
And she describes berry as a ‘complex’ flavour with lots of different chemicals.
Healthy immune cells (left) quickly cleared out bacteria which could threaten the mice’s lungs while those exposed to vapes (right) were not able to defend against the infection
Since the researchers only tested berry and menthol vapes they cannot say which flavours would be the most dangerous. However, they point out that the more complex a flavour is the more likely it is to cause harm (stock image)
‘We actually broke up the chemicals in vape that make up the berry flavour,’ Dr Thanabalasuriar added.
‘The individual chemicals did not have as adverse effects – it had to be the combination.’
However, since only two flavours were tested the researchers cannot conclude which individual flavours are likely to be the most harmful.
Likewise, since this trial was only conducted in mice it is not certain whether the results are directly applicable to humans.
But the researchers still warn that their findings show that more caution may be needed over flavoured e-cigarettes.
Dr Thanabalasuriar says: ‘We need to be careful about the types of flavours that we’re including in these products as they can have detrimental effects.
‘That’s really the take-home message, especially some of these vaping products that are marketed for kids.
‘The way they’re sold, the type of containers they are sold in – it’s very colourful, it’s really attractive to children, and this can be a really bad thing for our future.’
