I spent the first four years of my life with a bagel in hand. It often slipped from my fingers, at which point my mum would call over her shoulder, "Five second rule." That was my cue to pick it up off the floor and stick it back in my mouth.
First-time parents would look at my mother in disgust. You're really going to let her eat that? But think of all the germs!
Today my mum's attitude informs my perspective on germs, and current research supports her approach.
In the last century, increased sanitation led to dramatic improvements in public health, including decreased transmission of infectious organisms. But now we may be approaching a generation that is too clean for its own good. Anti-germ behaviours may actually increase the incidence of chronic conditions. In other words, our germaphobic tendencies today may inflict generations to come with asthma, allergies and other autoimmune diseases.
A 2015 study conducted by Bill Hesselmar of Sweden's University of Gothenburg found that children whose families washed their dishes by hand were significantly less likely to suffer from eczema than were children whose families used a dishwasher. These findings suggest that those who wash their dishes by hand are likely exposed to more pathogens, which actually protect them from the development of eczema. This study represents the latest data in support of the hygiene hypothesis.
In the late 1990s, Erika Von Mutius set out to study the rates of asthma and allergies in the former East and West Germany. Like other researchers at the time, she blamed air pollution for a rise in asthma. She assumed that children growing up in the less developed parts of East Germany would experience higher rates of allergies and asthma than those growing up in the more developed parts of West Germany. What she found was exactly the opposite. From that study she developed the hygiene hypothesis, positing that children who are exposed to more microbes earlier in life develop a greater immunity for the irritants that cause asthma.
According the U.S. Food and Drug Administration, an infant's environment can be too clean to properly educate a maturing immune system. Before birth, a child's immune system is suppressed to prevent him or her from rejecting maternal tissue. After birth, the immune system must evolve on its own. Without sufficient exposure to germs, the immune system never learns how to defend itself against infectious organisms. Defense mechanisms go awry and can actually contribute to the development of autoimmune diseases and allergies.
Evolutionarily speaking, humans developed in the presence of parasites and bacteria. In the words of Moises Valesquez-Manoff (author of the 2013 book An Epidemic of Absence), "the more one's surroundings resemble the environment in which we evolved - rife with infections and lots of what one scientist calls 'animals, feces and mud' – the lower the prevalence of" autoimmune diseases and allergies.
Type one diabetes, for example, is an autoimmune disease affecting the pancreas. While genetic factors may predispose a person to type one diabetes, environmental factors play a large role in disease onset. Findings published in the Journal of Clinical and Experimental Immunology in April of 2010, support the hygiene hypothesis, demonstrating that mice kept under germ-free conditions developed type one diabetes at a much faster rate than did mice kept under conventional conditions.
Most experts in the field agree that germs are necessary for healthy immune function. In 2009, Mary Ruebush published Why Dirt is Good: 5 Ways to Make Germs Your Friend. She says: "The typical human probably harbors 90 trillion microbes ... The very fact you have so many microbes of so many different kinds is what keeps you healthy most of the time." Ruebush denounces the current societal obsession with antibacterial products and suggests that plain soap and water are all that is needed for washing.
With this knowledge, it's clearly time to re-evaluate our perspective on germs. Rather than allowing phobia to rule what we buy and how we wash, we must come to accept germs as a reality of human existence, a requirement, in fact, for healthy living. How to we begin to change our relationship with germs? Maybe we begin by drinking from the tap, washing in moderation and employing the five-second rule, which I still apply.
The Baltimore Sun