The hygiene hypothesis is a theory used to explain why there has been an increase in allergies around the world.

What exactly is hygiene?

The World Health Organization (WHO) describes hygiene as conditions and practices that help to maintain health and prevent the spread of diseases, which means the things that you do to keep yourself and your surroundings clean to maintain good health. This might include bathing, dental care, handwashing, using clean water sources, keeping human and animal waste away from food and water, all with the goal of preventing infectious disease. This is a good thing, overall, we want clean and sanitary living conditions, but, in theory, it may be contributing to immune system confusion.

The hygiene hypothesis

This hypothesis proposes that as we have increased hygiene and decreased contact with organisms, or germs, in the environment, and in doing so have seen an increase in allergies. As infants and children, without contact with germs, the immune system does not get the training it needs to tell the difference between harmful or harmless substances. While there are likely to be multiple reasons for why allergies are on the rise, the hygiene hypothesis may play a role.

In developed countries, including the United States, we have done a good job limiting contact with and removing potential microbes, or germs, from our environment, which means there are fewer organisms to challenge our immune system. Studies have shown that people living on farms and people with pets have fewer allergies.

Fewer people live on farms with organisms that come from farm animals these days. And we now know what it takes to sanitize a bathroom or the hands of kids to eliminate the spread of germs, despite the fact that our immune system is equipped to battle those organisms.

So today, now that our bodies have less to battle, our ready-to-fight immune system now sees pollens and other environmental allergens as the invaders, triggering it to mount an immune response and creating allergic antibodies that are not truly out to cause us harm. Allergy testing can help determine if you have allergies.

So maybe this means going back to how our grandparents lived, which would mean encouraging kids to play outdoors, get dirty, play with pets, and allowing them to eat things off the floor, by ditching the “five second rule.”