The Skinny on How Diet Impacts Asthma

Back in the days before 32% of 2-18 year olds were overweight, obese or at risk of becoming so, no one thought anything of a little ‘baby fat’. That bubble is about to burst. With the rising numbers of childhood obesity, another illness is on the rise: asthma. Skeptical that the food you put in your pie hole has any influence on the air pipe just beyond it? Well, take a deep breath as we explore the evidence linking your diet and your lungs.

Both obesity and asthma have increased over the last 20 years. More obese kids have asthma compared with their healthy weight counterparts. Asthma is attributed to urbanisation: air pollution, tobacco smoke, less exposure to infectious agents, poor diet and poor lifestyle.

How is food affecting your lungs? Inflammation; This is a mechanical change linked to your diet. Having a higher body weight increases body inflammation and exacerbates lung and airway inflammation (see Figure 1). Diets that are high in calories, refined sugar, animal fats and low in plant products, combine to increase inflammation.

Figure 1: Pictorial representation of airway inflammation in people with asthma, during an asthma attack, compared to a normal airway. CDC, National Institutes of Health-National Heart, Lung, and Blood Institute, Asthma and Allergy Foundation of America, American Lung Association

A recent meta-analysis (combination and analysis of independent studies) of 48 studies demonstrates there is an association between body weight and asthma. Central obesity (around the chest and waist) increases asthma severity and decreases lung function (1, 2).

Evidence further linking airway problems and diet was demonstrated when adults with asthma ate a high fat meal and had increased airway inflammation following that meal. The same study found meals specifically high in trans fat had even more severe airway inflammation following the meal. In other words, fat makes it easy to be wheezy.

The good news is adults with asthma can improve their outcomes. Research shows asthma symptoms decreased in adults who lost weight.

Take a puff of your inhaler for this interesting morsel: babies who were breastfed for <2 months and were overweight, had increased incidence of asthma.

The take home points are:

• There is a multitude of evidence supporting an association between high body weight and asthma in children 
• Central obesity in children is linked with increased asthma severity and decreased lung function 

There’s nothing wrong with taking your child out to enjoy some ice cream or a burger every now and then. It comes down to ensuring that pint-sized pie holes are consistently eating a healthy diet to prevent ‘baby fat’ sticking around and affecting lung function.

Some practical tips:

• When enjoying ice cream out of the house, get the 'kiddie' size 
• If enjoying ice cream at home, use a small bowl and small spoon (it lasts longer) 
• If you're out for dinner as a family and want to get dessert, get one dessert with a spoon for everyone and share it