The recent increases in asthma and allergic diseases is believed to be caused, in part, by changes in our lifestyle, including our diet.
In particular, fast food consumption has increased. Children consumed 5 times more fast food in the 1990s compared to the 1970s. Fast food has been associated with wheezing in children, especially in boys. It is not yet known if fast food is also associated with increased asthma.
The rates of prolonged breastfeeding (breastfeeding for more than 3 months) have also increased since the 1970s. Some studies (but not all) suggest that prolonged breastfeeding is associated with less risk of asthma in children.
Researchers are confused as to why the increase in breastfeeding does not seem to protect children from developing asthma.
Our research questions:
- Why are asthma rates increasing despite the fact that more mothers are breastfeeding longer?
- Why is prolonged breastfeeding not protecting these children from getting asthma?
- Is the protective effect of breastfeeding changed by the increase in fast food?
723 SAGE children participated in this study. 246 with asthma and 477 without asthma. Participants answered questionnaires asking about breastfeeding and about diet, including eating fast food.
Children in the “Fast Food Group” were children who ate “burgers/fast food more than once or twice per week” in the past year compared to children who never or only occasionally ate burgers/fast food.
“Prolonged exclusive breastfeeding” was defined as feeding only breast milk for more than 12 weeks.
Children with asthma were more likely to consume fast food than children without asthma.
No junk food group: Asthma was less frequent in children who breast fed for more than 12 weeks. Breast feeding seems to have had a protective effect.
Junk food eating group: Prolonged breastfeeding was not associated with less asthma. Breastfeeding did not seem to have a protective effect.
Children who often ate fast food and who were not breast fed for long had the highest risk of asthma compared to children who were breast fed for longer and who did not eat fast food as they got older.
This study does not prove that fast food causes asthma but does show that fast food is associated with asthma in children.
The increase in breast feeding does not seem to have protected children from developing asthma. The protective effects of breast feeding may be lost when a child eats fast food more than twice per week.
More research is needed to better understand the role of high salt/high fat foods in the development of asthma.
Fast food consumption counters the protective effect of breastfeeding on asthma in children? Mai XM, Becker AB, Liem JJ, Kozyrskyj AL. Clin Exp Allergy. 2009 Apr;39(4):556-61. Epub 2009 Jan 22