Ever noticed that far more people have allergies than in the past? It seems that every second person in the big city is sneezing and sniffing at this time of year.

 

Well, it’s not your imagination. It’s true.

 

“Allergic disease has increased frequency mainly in the last three decades,” says Dr. Guy Delespesse, director of the laboratory for allergy research and a professor at the Centre Hospitalier de l’Université de Montréal.

 

The statistics show an alarming upward trend for asthma and allergies, almost doubling from 1980 to 1994, he says.

 

An astonishing three hundred million people worldwide suffer from asthma, and there are 250,000 deaths every year. It is estimated that the number of people with asthma will grow by more than 100 million by the year 2025.


It’s not just allergic disease that is on the rise, says Delespesse.


“The same thing is happening in immune-mediated diseases in the same period of time.”


Immune-mediated diseases are illnesses in which a person’s immune system backfires and attacks their own body. Examples are type-1 diabetes, multiple sclerosis and Chrohn’s disease.
Doctors have figured out that something in our environment must be causing these sharp rises in disease. If it was strictly a genetic change, it couldn’t happen that fast, says Delespesse.
It seems that people were better off when they lived on farms surrounded by animals and good, old fashioned dirt.


“Where allergies and asthma are the worst are where people congregate in large cities. Studies in Europe clearly demonstrate that children born and raised on farms, who have contact with animals, have a much lower incidence of asthma and allergies.”


In other words, the cleanliness of modern society may be causing disease. Bacteria in the environment — which move into our guts -— seem to be protective against allergies.


“There is evidence,” says Delespesse, “that the intestinal bacteria of children who will develop allergy is different from those who won’t develop allergies.”


Several possible solutions are being studied. One is to give probiotics to children who are at high risk for allergies, as this will boost the numbers of bacteria in their gut.


Another possible theory is that pregnant women need more zinc, magnesium, vitamin D and vitamin E in order to prevent allergies in their children.


Air pollution, especially diesel exhaust, is being studied as another possible culprit. Finally, the stress of living in a big city is thought to be a possible factor.


“This is a societal problem,” says Delespesse.


On an individual level, he suggests we continue to clean our homes and take antibiotics when recommended by a doctor, but recognize the overall effect that killing bacteria has on society.



Correction - May 26, 2010, 9:34 a.m. EST: A previous version of this story incorrectly identified the Centre Hospitalier de l’Université de Montréal. It has since been corrected.