Asthma in children is one of the most common chronic disease of that age group, with incidence rates rising within the past several
decades. Environmental factors, such as exposure to second-hand smoke and air pollution, are understood to have influence asthma rates in children, though more recently diet has been considered to be a potential factor as well.
A new study in the journal Indian Pediatrics aimed to examine whether or not diet is associated with asthma severity in Brazilian children.
A total of 268 children (age 3 to 12 years) with persistent asthma were recruited for this study (between two teaching hospitals in Brazil). An additional age-matched 126 children with intermittent asthma were used as controls. Asthma cases were categorized as mild, moderate, or severe.
Dietary habits, demographic information, socioeconomic information, mother’s lifestyle habits during pregnancy, environmental allergen exposure, family medical history (pertaining to asthma and other related diseases) were collected during interviews with children and their parents.
Maternal smoking during pregnancy, preterm birth, and child obesity were positively (and significantly) associated with asthma severity in children.
There was no association between diet and asthma severity in children.
As research has shown previous, this study confirms that maternal smoking is positively associated with asthma severity in children. In other words, the more mom smoked during pregnancy, the more severe the asthma in her child.
Additionally, preterm birth and child obesity were also positively
associated with asthma severity in children.
However, in regards to diet, this study showed that diet type (including a Mediterranean-style diet) was not associated with asthma severity in children. There were no healthy controls (i.e. no asthma) in this study, so it can’t be said with certainty whether or not asthma prevalence in general is linked to diet, but this study does seem to show that asthma severity is not related to diet in any way.
Does maternal diet during pregnancy have any influence on health outcomes of children relating to allergies? How about when the mother is
breast-feeding that child? Does her diet then have an influence on the child’s health?
A recent review performed a meta-analysis on 42 studies with a total of greater than 40,000 children to see if maternal diet during pregnancy and during lactation (breast-feeding) played any role in the health of those children.
The studies included in the review varied in nature in terms of their experimental protocols: 11 were intervention studies, 26 were prospective cohort studies, 4 were retrospective cohort studies, and 1 was a case-controlled study. Comparing studies with different experimental designs can be somewhat problematic, but there are ways to compare on a more broad scale.
There were no significant differences overall in eczema or asthma cases in the offspring of mothers eating a diet free of common food allergens. Some of the studies did note some associations, though nothing statistically significant was found.
One of the few consistent associations found related to those mothers consuming diets containing a lot of fruits, vegetables, fish, Vitamin D-rich foods, and in general foods pertaining to the Mediterranean diet. Children of these mothers were found to be associated with a lower risk of allergic disease.
Foods in the diet of pregnant and lactating mothers that were associated with a higher risk of allergic disease in children included vegetable oil, margarine, nuts, and fast food.
While this meta-review did not find statistically significant differences, it does provide some insights that a Mediterranean-like diet may consistently provide some benefit to their offspring in terms of a reduction in allergic disease prevalence. It can be difficult to compare studies that used markedly different experimental designs after the fact, so this positive association should indicate a need for further research on this topic.