Asthma is one of the most common health complaints in children. One in five children now suffer from the complaint, roughly twice the number affected just 10 years ago. Research published in The Lancet this month suggests that not only asthma, but wheezing in general, is becoming increasingly common. The authors of the study seem at a loss to explain the explosion in asthma and wheezing rates witnessed over the last decade. However, this week, research published in the medical journal Thorax suggests that asthma in children is related to the consumption of supposedly healthy ‘polyunsaturated’ fats found in margarine and vegetable oils. This study further confirms recent research from Finland which found a link between childhood allergic conditions and polyunsaturated fat. Could it be that the rise in asthma rates seen recently is down to changes in diet?
Within the lungs are tubes known as bronchi and bronchioles. These allow air to be passed in and out of the lungs so that oxygen can be absorbed from the atmosphere and carbon dioxide, a waste product, can be eliminated. The bronchi and bronchioles are lined with muscle which may become constricted, impeding the flow of air in and out of the lungs. Asthma is a condition characterised by constriction of the airways, and often manifests as episodes of breathlessness and wheezing. Conventional medical treatment for this condition is based around drugs which help open up the airways (called bronchodilators) and steroids which help damped the immune response responsible for inflammation and constriction of the lung tissue.
It is well known that certain foodstuffs may promote inflammation in the body, which can then perhaps contribute to asthma and other allergic conditions such as eczema. Some of the foods which may do this are what are known as the omega-6 fatty acids. Omega-6 fats are generally found in quantity in margarine and vegetable oils such as sunflower, safflower and corn oil. Omega-6 fats are known to be converted in the body into substances which tend to encourage inflammation in the body. On the other hand, fats of the omega-3 type, such as those found in oily fish, appear to have the ability to reduce inflammation in the body.
As far back as 1994 researchers put forward the idea that an increased consumption of omega-6 fats, coupled with a decreased consumption of omega-3 fats, might increase the risk of asthma. A study published in the Australian and New Zealand Journal of Medicine found that in Australia, the increased rates of asthma coincided with a five-fold increase of polyunsaturated fats, particularly of the omega-6 type. This research also noted the increased consumption of these fats in New Zealand, United States and the UK, all places where asthma rates are rising significantly. This week’s research only goes to strengthen the theory that the fats found in many processed foods can provoke allergic conditions such as asthma.
In contrast, the consumption of what are known as omega-3 fatty acids (such as oily fish) is associated with a lower risk of asthma. Countries where omega-3 fat consumption is high (such as Mediterranean and Scandinavian nations) have low rates of asthma. Research published in 1996 also showed that asthma symptoms appeared to be better controlled in children who consumed oily fish. Avoidance of margarine and processed vegetable oils, and the inclusion of oily fish such as salmon, trout, tuna, mackerel and herring in a child’s diet may possible help control asthma symptoms in time.
Another factor which appears to be of significance in asthma is food sensitivity. Studies have shown that it is possible for individuals to have their asthma symptoms triggered through the consumption of specific foodstuffs. Research in this area dates back to the 1950s. Food sensitivity is thought to account for two-thirds to three-quarters of cases of childhood asthma. While any food, potentially, can create problems the most recent research in this area suggests that the most common culprits as dairy products (particularly milk and cheese) and wheat. In clinical practice, it is often found that dairy products and wheat tend to worsen asthma symptoms in children. A trial of a diet which excludes these foods is therefore often worthwhile. Good alternatives include rice milk, oatcakes and oat and corn-based breakfast cereals. Another option is to have a child’s individual food sensitivities assessed. Many health foods stores offer a form of testing (Vega testing) which is relatively economical, and can sometimes help to pinpoint problem foods. Once problem foods are excluded, improvements are generally seen in 1 – 4 weeks.