The Cause of Allergies
The allergy epidemic
Allergies are on the rise. Food allergies worldwide have increased from 3% of the population in 1960 to 7% in 2018; asthma and seasonal allergies have increased at a similar rate.1 Our homes are full of allergy meds, our food labels have more text than ever, and the peanut-free tables are getting crowded. Something about our modern way of life is leading to allergies.
Allergies and genetics
You may have heard of the genome before. Simply put, the genome is the genetic information of an organism. It turns out that something like a peanut allergy is not linked to genetics the same way that your eye color is. A person's eye color is determined almost exclusively by their genetics. However, for a peanut allergy, there are no genes that definitively say, "you are allergic to peanuts."
There are genetic mutations that seem to predispose people to develop allergies. One such genetic mutation in the filaggrin (FLG) gene can impair the barrier function of the skin, an essential factor in allergy development that we will detail later in the course. People with mutations in the FLG gene are statistically more likely to develop allergies; however, it is far from a certainty.(113, 114) Just because someone has a genetic predisposition for something does not mean it will materialize.
When it comes to disease, humans are starting to learn that there is more to the equation than just the genome. Allergies have been elusive to modern-day medicine because we have been looking at the problem the wrong way.
To understand what leads to allergy, we must look beyond the genome.
The exposome
The exposome is the sum of all the exposures of an individual. Exposures are the environmental or lifestyle factors that interact with us; the food we eat, the air we breathe, the organisms we interact with, and so on.(2, 3) These exposures have potent effects on our health.
Compared to the genome, the exposome has a much more significant impact on allergy development. So if we expose our children to the wrong things, their risk of developing allergies increases, but if we expose them to the right things, we can give them the best chance at an allergy-free life.