Have allergies always been this prevalent?
It is estimated that 30-40% of the world population suffers from some sort of allergic condition. These reactions are an invaluable body process designed to protect us from harmful substances. However, it can be less than desirable when this reaction makes it hard to enjoy the outdoors and furry friends or plain dangerous to indulge in some of your favorite foods. Additionally, it isn’t uncommon for people to suddenly develop a new allergy.
Specifically looking at food allergies, 10% of U.S. adults are estimated to be affected. Furthermore, about half of these people have reported developing a new reaction to food that did not happen when they were a child. This doesn’t make sense– if the body is trying to help us, why is it overreacting to otherwise harmless foods and other compounds?
Why do we develop these “random” allergies?
Immunity is incredibly complicated, and scientists are still working to uncover why humans are increasingly plagued by these unwelcome allergic reactions. The biggest suspects are the changes that have occurred alongside modernization since these developed alongside heightened allergic responses. Furthermore, there is no evidence that any wild animals exhibit allergic reactions, even today. The only exception are house pets which have developed more allergies alongside their humans. There are several current hypotheses, but it is still unclear which ones are valid and contribute the most to this phenomenon.
One of the suspected culprits is increased hygienic practice, such as handwashing, that accompanied modernization. This minimizes exposure to germs, preventing illness, but it also washes harmless allergens away before our body can recognize them as such. This avoidance of dirt, germs, and other natural substances that we have evolved alongside just makes it more likely that you will develop a reaction once you are inevitably exposed to these products later in life. For example, if a child grows up without touching grass until they are 10 years old, once they finally touch it, their mature immune system will be startled by the introduction of something totally new and may create some of these pesky antibodies that cause itching, hives, sneezing, etc. It has become clear that exposure to allergens can actually be a good thing, especially for children. Just as it’s easier for children to soak up language like sponges, their immune systems are also incredibly malleable.
Can allergies be prevented?
One large research project in London called the LEAP study uncovered that feeding infants peanut products prevents the development of peanut allergies down the line. This suggests that by exposing the body to these products through the digestive system can prevent the immune system from registering these as harmful allergens in the future. This aligns with the science which has shown that the immune system is adaptable and learns rapidly during the first 3 years of life. After this point it becomes much more sensitive and less willing to accept foreign bodies, such as peanuts and dust mites, as harmless.
Another interesting study found younger children have less allergies than their older siblings. One theory to explain this is that the youngest children were constantly exposed to germs and other things brought home by their older siblings. Through repeated exposure to various substances, their immune systems are trained to not view these as allergens, and consequently not mount immune system overreactions that cause allergies later in life. This pattern of exposure is unique to the younger children and is just one idea that may explain why they have less allergic reactions than their elder counterparts.
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Assessed and Endorsed by the MedReport Medical Review Board