An allergy is an abnormal reaction of the immune system, in response to an otherwise benign substance. Allergies are one of the leading chronic diseases in Canada and the U.S., with an estimated 55% of the total population testing positive to at least one allergen. Unfortunately those numbers are on the rise, and food allergies in particular are becoming ever more prevalent amongst the general population. Conventional medicine offers no cure for allergies and no preventative measures when it comes to contracting them. Fortunately, a recent study led by researchers at the University of Bristol’s School of Veterinary Science, has made a discovery that could eventually lead to preventative actions which can be taken during infancy in order to prevent allergies from developing.
The study which was published in the February 2012 edition of the Pediatric Allergy and Immunology Journal, found that growing up on a farm results in immune system alterations that reduces an individual’s risk for developing allergies and allergic reactions. According to lead researcher Dr. Marie Lewis:
“Many large-scale epidemiological studies have suggested that growing up on a farm is linked to a reduced likelihood of developing allergic disease. However, until now, it has not been possible to demonstrate direct cause and effect: does the farm environment actively protect against allergies, or are allergy-prone families unlikely to live on farms?”
The study was conducted on piglets because they contain many of the same genetics, immunity functions, metabolic mechanisms and physiological aspects as humans. There were two sets of piglets; the first of which was nursed by their mothers and reared on a farm. Their siblings on the other hand, were fed formula milk and spent their early life in an extremely hygienic isolator unit, in order to mirror the sterile lifestyle and environment that human babies are most often raised in.
According to the study, the piglets raised on the farm demonstrated a reduced antibody response to novel food proteins when they were weaned. In other words, they were less likely to experience allergic reactions to a common food allergen. The researchers concluded that early-life exposure to certain environmental components of farms, positively impacts regulatory mechanisms of the immune system and thereby helps to reduce the risk for developing allergies.
The researchers found that the farm-raised piglets had a reduced number of stimulatory T-lymphocytes (a type of white blood cell) in their intestinal tissues. This is significant because T-lymphocytes are the immune cells that fuel the immune system responses that ultimately cause allergic reactions. The farm raised piglets also had higher numbers of regulatory T-cells, which are a subgroup of T-lymphocytes that reduce inflammation and regulate the immune system. More specifically, regulatory T-cells help to prevent an over-reaction by the immune system and immune disorders such as allergies are thought to be caused, at least in part, by low amounts of the regulatory T-cells.
More research needs to be done in order to determine the exact way in which farm living works as a preventative measure against the development of allergies. Previous research has found that intestinal bacteria (acquired in infancy) play a pivotal role in the development of a healthy immune system and perhaps the farm environment allowed for a greater flourishing of the beneficial bacteria. The researchers at Bristol’s School of Veterinary Science speculates that factors such as aerial contaminants, antigens from bedding, social and maternal interactions and early nutrition may also have played a preventative role in the development of allergies in the farm raised piglets. Whatever the explanation, Dr. Lewis and her research associates are optimistic that further investigations will eventually lead to a way to prevent not only allergies, but all types of immune system disorders.
Related Reading: The Link Between Allergies and Exhaustion