The flavourings used in electronic cigarettes may damage blood vessels in the same way as heart disease, according to research.
Although using e-cigarettes, or ‘vaping’, is claimed to be healthier than smoking tobacco, evidence suggests it is still bad for your body.
The chemicals used to give the vapour flavours, such as cinnamon, strawberry and banana, may cause inflammation in cells in the arteries, veins and heart.
They causes the body to react in a way that mimics the early signs of heart disease, heart attacks or strokes, the study found.
All nine of the chemicals tested by the scientists at Boston University killed blood vessel cells, but menthol, clove, vanilla, cinnamon and burnt flavourings produced worse reactions than others.
Menthol and clove flavours may even cause damage similar to that seen in people who smoke traditional cigarettes.
The damage is done by the flavourings reducing levels of nitric oxide in the blood vessels, which makes them more likely to swell or clot, and reduces their ability to expand when there is more blood – which could lead to higher blood pressure.
E-cigarettes are marketed as being healthier than tobacco, but scientists say they may still be bad for you
The researchers tested the chemicals in lab conditions at levels people could be expected to inhale.
Assistant professor of medicine Dr Jessica Fetterman said: ‘Our findings suggest that these flavouring additives may have serious health consequences.
‘Flavourings are directly toxic to blood vessels’
‘Flavouring additives themselves were directly toxic to blood vessels and have adverse effects that may have relevance to cardiovascular toxicity similar to combustible cigarettes.
‘Increased inflammation and a loss of nitric oxide are some of the first changes to occur leading up to cardiovascular disease and events like heart attacks and stroke, so they are considered early predictors of heart disease.’
Scientists tested the short-term effects of menthol, burnt, vanilla, cinnamon, clove, butter, strawberry, banana and spicy cooling flavours on endothelial cells, the cells which line the blood vessels and the inside of the heart.
They found all flavours increased inflammation and reduced nitric oxide in the heart cells.
E-cigarettes marketed as safer than tobacco
Dr Fetterman explained the popularity of e-cigarettes has increased dramatically since they were introduced in 2003.
She adds they are popular among ex-smokers and young ‘vapers’, and are marketed as being safer than tobacco cigarettes.
VAPING MAY CAUSE CANCER OR PNEUMONIA
Separate studies published earlier this year suggested smoking e-cigarettes could cause DNA mutations which lead to cancer, and enable pneumonia-causing bacteria to stick to the lungs easier.
Researchers at New York University subjected human bladder and lung cells to e-cigarette vapor, which is marketed as being healthier than tobacco.
They found the cells mutated and became cancerous at a much higher rate than expected, and mice exposed to the smoke also suffered significant DNA damage.
The team warned their findings bring into question the popular belief that vaping nicotine is a safe alternative to smoking it in cigarettes.
In another study, scientists at Queen Mary University, London, found vaping makes users more likely to catch pneumonia – just like smoking tobacco or breathing in traffic fumes.
The vapour from e-cigarettes helps bacteria that cause the condition to stick to the cells that line the airways, they said.
The effect occurs with traditional cigarette smoke and those who are exposed to air pollution high in particulates from vehicle exhausts.
There are around 7,000 different flavours on the market, Dr Fetterman says, with menthol, sweet and fruity liquids being the most popular.
She said: ‘The flavourings used in tobacco products, including electronic liquids, greatly increase the appeal of tobacco products and mask the harshness associated with use.
‘Flavourings are also a driver of youth tobacco use and sustained tobacco use among smoker.’
But Dr Fetterman noted while the health effects of traditional cigarettes are well-established, the dangers of e-cigarettes have not yet been extensively studied.
How the research was carried out
Endothelial cells – those from the heart and blood vessels – were collected from non-smokers, non-menthol cigarette smokers, and menthol cigarette smokers.
Both groups of smokers had a similar lack of nitric oxide production.
When the non-smokers’ cells were treated with a menthol or clove flavouring they showed the same damage that was seen in the smokers’ cells.
All flavours caused damaged at the highest levels tested, but cinnamon, clove, strawberry, banana and spicy cooling all caused damaged at lower concentrations.
Strawberry had the same effect even at very low levels, suggesting cells are particularly sensitive to it.
While the study directly tested effects of just the flavourings at levels likely to be reached in the body, it did not heat them as an e-cigarette would, or include other chemicals.
The scientists have not tested the effects of the chemicals inside a human body.
The chemicals tested were menthol (mint), acetylpyridine (burnt flavor), vanillin (vanilla), cinnamaldehyde (cinnamon), eugenol (clove), diacetyl (butter), dimethylpyrazine (strawberry), isoamyl acetate (banana) and eucalyptol (spicy cooling).
Dr Fetterman added: ‘We still don’t know what concentrations of the flavourings make it inside the body.’
The study was published in Arteriosclerosis, Thrombosis and Vascular Biology, an American Heart Association journal.