Asthma is a common lifelong disease characterized by inflammation of the respiratory airways and airflow obstruction. Although the specific cause is unknown, asthma is linked to several genetic and environmental factors causing the immune system to react to the patient’s airways and causing symptoms and complications. Symptoms experienced by patients include recurrent episodes of wheezing, shortness of breath, coughing and chest tightness and can be worse in the early morning and at night or after exercise or exposure to cold air.
Two new studies have offered insight into the preventable risk factors for the development of asthma during childhood. Professor Anthony Seaton has been investigating the influence of the diet on the development of asthma for more than 20 years. These studies give further support to this “dietary hypothesis” for the onset of asthma and to justify the increase of the prevalence of asthma in the last few decades. These studies led by Professor Graham Devereux and Dr Steve Turner from the University of Aberdeen, Scotland, were recently published in the European Respiratory Journal and Clinical & Experimental Allergy.
In the studies, researchers observed levels of vitamin D and E in early pregnancy and then looked into two outcomes. First, they analyzed the link between low levels of maternal vitamins D and E and the development of asthma until 10 years of age in their children. Then, in a separate group of mothers, they studied the response to environment factors such as dust or infection of cells from the inner lining of airways from babies with low vitamin D and E levels compared to normal ones.
Results show that maternal diets with low levels of vitamin D and E are associated with an increase in risk of development of asthma until 10 years of age. The long follow-up is important as it shows that the pregnant woman’s diet is important throughout the life of her child.
Moreover, the other study shows that airway cells (swabs taken from the inside of the nose) of newborns of mother with vitamin D and E deficient diets react more to irritants and allergens (substances that cause irritation and immune response).
These studies show a potential association between a low vitamin D and E diet and asthma. Nevertheless, the women’s diets are surely closely linked to their lifestyles and there are several confounding factors not taken into account. In the future, a clinical study of mothers taking vitamin D and E supplements vs placebo no treatment) is warranted to give a more definitive answer to this question.