It's true that asthma and diet are related, at least that's the conclusion of a recent international study. Using data from more than 319,000 teens ages 13 and 14 in 51 countries and more than 181,000 children ages six and seven in 31 countries, the study team found an association between fast food and severe asthma, eczema, and rhinoconjunctivitis (a runny or blocked nose accompanied by itchy and watery eyes). All three of these conditions are allergic in nature. While the findings don’t prove that the fast food was responsible, it raises a strong possibility that it might be. The researchers noted that fast food tends to have high levels of saturated fat and trans-fatty acids, which are known to affect immunity.
Overall, the study found that consuming three or more fast food servings per week was associated with a 39 percent increased risk of severe asthma among the teenagers in the study and a 27 percent increased risk among the little kids, as well as with the severity of rhinitis and eczema in both groups. I think these findings speak to the pro-inflammatory nature of fast foods.
There was some good news from this study, too: the investigators found that eating fruit appeared to protect children against all three conditions and protect the teens from severe asthma and rhinitis. Three or more weekly portions of fruit were associated with a decrease in symptoms by 11 percent among teens and by 14 percent among the children. The protective effect probably is due to the abundant antioxidants and other beneficial compounds in fruit.
The researchers gathered the data for the study by quizzing the teenagers and the parents of the little kids about symptoms of asthma, eczema and rhinoconjunctivitis that had occurred during the past year and how much they interfered with daily life and sleep patterns. The parents and the teens were asked about whether they related certain types of food to symptoms or to improvements in health. They were also asked about their weekly diets.
After weighing the information on diet –how often the study participants ate meat, fish, fruits and vegetables, cereals, bread, pasta, rice and other common foods, as well as how often they consumed fast food - the researchers concluded that fast food was associated with severe symptoms of allergic asthma, eczema and rhinitis among the teenagers. Among the young kids, fast food was linked to allergic asthma and rhinitis but not to current cases of eczema. However, fast food wasn’t linked with current and severe asthma in six and seven year olds living in poorer countries.
The youngsters participating in the study – both the teens and the children – were part of the International Study of Asthma and Allergies in Childhood (ISAAC) that enrolled nearly two million children in more than 100 countries. It was published online on January 14, 2013 by the journal Thorax.
Andrew Weil, M.D.