The years following World War II and the second Industrial Revolution brought with them the unprecedented proliferation of processed foods, cigarette smoke, and diesel exhaust. This era also marked the beginning of our obsession with being “clean,” with the introduction of chemical-powered laundry and dishwasher detergents, household cleaning agents, and even cosmetics. More than 350,000 new chemicals purporting to make our clothing, dishes, and skin cleaner have been introduced since 1960.
As an immunologist with four decades of experience in researching allergy, asthma, autoimmune disease, and other chronic conditions, I know that the introduction of these chemicals has not been without consequence. These substances have played a pivotal role in the global, epidemic-level rise in chronic health conditions over the past 75 years.
The surfaces of our skin, respiratory tract, and gut are lined with protective cellular layers known as epithelial barriers. Epithelial barriers protect against infections, toxins, pollutants, and allergens.