Allergy protection may occur in early childhood, says expert
In addition, having a household pet such as a cat or dog in the first year of life may have a protective effect. However, after the first 12 months of life, introducing animals, particularly cats, to the household, puts a child at risk of developing asthma.
Dr James Martin, a consultant respiratory physician, said it appeared exposure during the first year of life to certain allergens — substances that trigger the immune system to fight against itself — could lessen the risk of developing allergies.
This theory, known as the “hygiene hypothesis”, could explain the lower incidence of allergy in children living on farms, possibly owing to more exposure to bacteria at an early stage.
It could also explain the lower incidence of allergy in children of large families, possibly owing to exposure to infection from older siblings, and the lower incidence of asthma among children who spend time in daycare.
“If they go into daycare, they are more likely to get infections as a virus is passed from one child to the next, and this may actually help the immune system develop in a more normal way,” said Dr Martin.
However, this protection does not appear to arise beyond the first 12 months of life.
Dr Martin, who will deliver a presentation on asthma tonight at a public forum at University College Cork (UCC), said in addition to allergens, bacteria in the gut (intestinal flora) may also affect the immune system. Alterations of these flora, for example through antibiotic use or diet, may, Dr Martin said, “lead to changes in the composition of the flora with unfavourable effects on the maturation of our immune systems”.
“If there is an imbalance in the bowel flora, this may throw off the development of the immune system and make it more prone to allergies,” said Dr Martin.
However, research Dr Martin is undertaking at the alimentary pharmabiotic centre at UCC is examining the potential therapeutic value of probiotics in reducing the risk of developing allergic diseases such as asthma.
“Again, the treatment would have to happen very early in life,” said Dr Martin.
Dr Martin’s presentation, entitled Asthma — The Modern Epidemic, is one of several presentations to form part of tonight’s forum, entitled Common Ailments — From Allergies to Asthma.
Dr Martin, who is from Cork but based at McGill University in Montreal, is at UCC on foot of a Walton fellowship award courtesy of Science Foundation Ireland.
Tonight’s forum, which will get under way at 7pm at UCC’s Brookfield Health Science Complex, will also include discussions on obesity and diabetes.
