A diet of fast food and takeaways may be behind the steady surge in children’s asthma and allergies affecting the UK and other developed countries, according to a study.
An international collaboration of scientists has found that young teenagers in particular are nearly 40 percent more likely to have severe asthma if they eat burgers and other types of fast food more than three times a week.
For children aged six to seven the risk increased by 27 percent. Children eating fast food were also more likely to get severe eczema and rhinitis — a condition where the nose blocks or runs and the eyes become itchy and watery.
The scientists, from New Zealand, Spain, Australia and Germany as well as Nottingham in the UK, say their study could have “major public health significance owing to the rising consumption of fast foods globally” if the link they have found turns out not to be coincidence, but causal.
The good news was that eating fruit appeared to protect young people from asthma and allergies. Eating three or more portions a week reduced the severity of the symptoms by 11 percent among teenagers and 14 percent among younger children.
The research, published in the journal Thorax, part of the BMJ group, came out of a large collaborative project called the International Study of Asthma and Allergies in Childhood (ISAAC), which involves nearly 2 million children in more than 100 countries, making it the biggest of its kind.
Fast food — the authors specifically mentioned burgers only because it was the reference to fast food that most people would understand — was the only food type associated with asthma and allergies across all age ranges and countries.
The authors said that “such consistency adds some weight to the possible causality of the relationship.”
However, they said more research would be needed to discover whether fast food is definitely a problem.
The fast food link was stronger among teenagers than among the young children, which the authors suggest may be because adolescents have more independence, money and control over what they eat.
The paper says a link between fast food and asthma and allergies is biologically plausible. It could be “related to higher saturated fatty acids, trans fatty acids, sodium, carbohydrates and sugar levels of fast food and possibly preservatives.”
In the teenagers, eating butter, margarine and pasta was also associated with asthma symptoms.
Studies which involve asking people about their diet can be problematic, because people either forget or tailor the truth. Professor Hywel Williams, from the center of evidence-based dermatology at Nottingham University, said recall over the 12 months of the study was more likely to be inaccurate than biased and this would tend to dilute any association between fast food and asthma, rather than the reverse.
“Now if there was a widespread belief already out there that fast foods are ‘bad’ for allergies, then you could say the data was simply reflecting such prior prejudices/beliefs, but we are not aware of any such widespread prior belief,” he said.