Mediterranean Diet may prevent asthma in children

The American Lung Association reports that asthma is the most common chronic condition among children, affecting over 5 million children. It is the third most common cause of hospitalization in kids under 18, and in 2013 alone accounted for over 13 million days absent from school.

Genetic factors and viral infections of the lungs and airway early in childhood are among the most common causes of asthma, but we do know of ways to help reduce the risk of children developing asthma, including a healthy prenatal diet that includes seafood, avoiding smoking during pregnancy and after the child's birth, and breastfeeding.

Certain dietary factors have also been linked to lower risk of asthma, most notably the antioxidants in fruit. But as a team of researchers noted recently in a study published in the journal Public Health Nutrition "People consume a variety of foods and food groups in a meal, rather than individual nutrients or food groups." They noted that it made more sense to look at overall dietary patterns rather than focusing on single foods or food groups, and conducted a review of the existing research that looked at a Mediterranean-style diet in relation to childhood asthma (2017;20(15):2722-2).

The authors identified 15 studies that assessed the diets of over 100,000 children between the ages of 1 and 19 using Food Frequency Questionnaires filled out by the children's parents or the children themselves. Their diets were then assigned Mediterranean Diet scores and their asthma symptoms correlated with their scores.

The majority of these articles (11 of them) were cross-sectional studies, and nearly all showed an inverse association between Mediterranean Diet score (higher score meaning better adherence) and asthma symptoms. As these types of studies are a snapshot of a single moment in time, we can't conclude that a better Mediterranean Diet score prevents asthma, but it's certainly something to take note of.

On the other hand, two of those cross-sectional studies showed no association between Mediterranean Diet score and symptoms, and 1 actually showed an increase in symptoms in 6-7 year old girls. One of the studies showing no association, however, was flawed in that it did not use a standardized tool to evaluate the severity of the symptoms.

The other five studies included in the review were either case-control or cohort studies. Case-control studies match characteristics such as age, sex, and Body Mass Index of persons with a condition with others with the same characteristics but without the condition in an attempt to determine why one person has the condition and the other does not.

The case-control study suggested that higher Mediterranean Diet scores were associated with lower incidence of wheezing and other asthma symptoms. The two cohort studies showed statistically significant association between greater Mediterranean Diet score and less wheezing, and the single prospective study in asthmatic children under five showed that higher Mediterranean Diet scores meant improved lung function and decreased number of episodes and hospital admissions.

What this means for you

For the research community as a whole this means that more research into the effects of a Mediterranean-style diet on asthma is worth pursuing. For you as a parent, however, this is just another reason for you to start your kids off on the right foot with a healthy diet that's long on familiar foods and familiar flavors, like a Mediterranean-style diet. Read about the nine points of a Mediterranean-style diet and how they are part of the foods you love.

First posted: January 17, 2018