Eating three or more burgers a week may boost a child's risk of asthma and wheeze - at least in developed nations - reveals a large international study, published in Thorax.
Conversely, a Mediterranean diet, rich in fruit, vegetables, and fish seems to stave off the risk, the research shows.
The research team base their findings on data collected between 1995 and 2005 on 50,000 children between the ages of eight and 12 from 20 rich and poor countries around the world.
Their parents were asked about their children's normal diet and whether they had ever been diagnosed with asthma and/or have had wheeze. Just under 30,000 of the children were tested for allergic reactions, to see if diet also influenced their chances of developing allergies.
Mediterranean diet best
Diet did not seem to be associated with becoming sensitised to common allergens, such as grass and tree pollen. But it did seem to influence the prevalence of asthma and wheeze.
High fruit intake was associated with a low rate of wheeze among children from rich and poor countries.
Similarly, a diet high in fish protected children in rich countries, while a diet rich in and cooked green vegetables protected children against wheeze in poor countries.
Overall, a Mediterranean diet, high in fruit, vegetables, and fish was associated with a lower lifetime prevalence of asthma and wheeze.
But eating three or more burgers a week was associated with a higher lifetime prevalence of asthma and wheeze, particularly among children with no allergies in rich countries. A heavy meat diet, however, had no bearing on the prevalence of asthma or wheeze.
The authors say that fruit and vegetables are rich in antioxidant vitamins and biologically active agents, while the omega 3 polyunsaturated fatty acids found in fish have anti-inflammatory properties, so there are biologically plausible links for the findings.
Burger consumption could be a proxy for other lifestyle factors, they add, particularly as the increased asthma risk associated with it was not found in poor countries. - (EurekAlert, June 2010)