Fruit-flavoured shisha could be more damaging to smokers’ health than unflavoured pipe tobacco, new research suggests.
Scientists at UAE University found that mice exposed to apple or strawberry-flavoured shisha underwent harmful biochemical changes not seen in those that breathed unflavoured shisha smoke.
Shisha cafes have been shutdown this week across much of the UAE due to fears over coronavirus, with sharing pipes more likely to pass on infections.
The new research is the latest study to reveal already well-known health risks associated with smoking shisha, a common pastime in the Emirates.
Thousands of people across the country indulge in the habit on a daily basis, often opting for popular flavours including mint, orange, cherry or grape.
"Overall, the toxicity of flavoured tobacco WPS (waterpipe) smoking, in particular strawberry-flavoured WPS, was found to be greater than that of unflavoured WPS," the researchers wrote in their paper in Oxidative Medicine and Cellular Longevity.
“The current experimental findings provide biological plausibility for the harmfulness of flavoured tobacco used in WPS and support calls for interventions to counteract the increase of attractiveness and use of WPS, particularly among young people.”
Mice used in the new study were exposed to shisha smoke for 30 minutes per day, five days a week for one month.
Tissue samples were analysed biochemically to look for inflammation and “oxidative stress” – the presence of certain highly reactive chemical substances.
Oxidative stress and inflammation can result in DNA damage and are associated with an increased cancer risk in smokers.
The researchers found that mice exposed to apple and strawberry-flavoured shisha had higher levels of certain chemicals linked to inflammation than mice exposed to unflavoured shisha.
Similarly, flavoured shishas were associated with higher levels of some chemicals linked to oxidative stress.
The same team of scientists, led by Professor Abderrahim Nemmar at UAE University, also recently published a study using mice in the International Journal of Molecular Sciences indicating that apple-flavoured shisha produced greater harmful effects on the heart than unflavoured shisha.
The finding that flavourings could be harmful is “not particularly surprising”, said Professor Gordon Ferns, a professor of metabolic medicine and medical education at Brighton and Sussex Medical School in the United Kingdom who has researched shisha’s health effects.
“The flavourings will likely be due to their content of aromatic compounds and these may be prone to modification and lead to chemical chain reactions that lead to reactive chemical species that may in themselves be injurious,” said Professor Ferns, who was not connected with the study.
Because the research involved mice and was undertaken in “carefully controlled conditions”, he said it was difficult to draw conclusions about health effects on humans, but that “the impact on inflammation appears to be consistent with other studies”.
The inflammation caused by shisha smoking may, he said, affect several chronic conditions, including cardiovascular disease and diabetes.
“It is possible that flavoured shisha may have a greater impact on these clinical outcomes, and perhaps increase the likelihood of shisha smoking in young adults and perhaps children,” he said.
Dr Mohanad Diab, a consultant oncologist at two NMC hospitals in Abu Dhabi, said that “for sure” better regulation over what substances were used to flavour shisha was needed.
Earlier studies, he said, found that companies producing shisha flavours did so under poorly regulated conditions using “cheap and harmful materials”.
Smoking shisha for one-and-a-half to two hours can be equivalent to smoking 10 packets of cigarettes, according to Dr Diab.
“We in the medical field have started to request [that] our patients, if they can’t stop shisha, replace it by normal smoking,” he said.
Many other risks associated with smoking shisha have previously been highlighted, according to Hazel Cheeseman, director of policy for the UK-based anti-smoking organisation Action on Smoking and Health (ASH).
Evidence indicated that it more than doubled the risk of lung cancer, respiratory illness, low birthweight and gum disease.
“Although shisha smoking has not yet been as extensively researched as cigarette smoking, the existing research suggests that it is associated with many of the same risks as cigarette smoking and may incur some unique health risks too,” she said.
As well as the tobacco and – it now appears – the flavourings, additional risks are known to come from the charcoal used.
“The smoke contains not just burned tobacco smoke, but particles from charcoal, which if anything is going to worsen the impact of tobacco smoke,” said Professor Kamran Siddiqi, a professor in public health at the University of York in the UK, who has also researched shisha.