The rising fear of allergies prompted parents and doctors to adopt avoidance strategies. This avoidance, however, was the biological cause of the allergies, creating a vicious feedback loop where fear led to actions that generated more of the thing being feared, thus reinforcing the initial fear and behavior.

Humans evolved a robust inflammatory response to fight constant threats like infections. In today's relatively sterile world, this powerful system lacks its historical targets and can overreact to modern triggers, leading to the chronic low-level inflammation that is at the heart of many modern diseases.

The rise in consumer cleaning products and spick-and-span households reduces our exposure to diverse microbes. According to the hygiene hypothesis, this lack of immune system training can make our bodies less robust and more prone to overreacting to benign substances like food proteins, thus fostering allergies.

Babies born via C-section are colonized by skin bacteria, not the beneficial bacteria from the birth canal. This establishes a different, potentially less healthy, lifelong gut microbiome, contributing to a rise in allergies and autoimmune diseases.

The widespread medical recommendation for young children to avoid peanut butter until age 3 was tragically wrong. This advice ignited the modern peanut allergy epidemic by preventing the early exposure necessary to build immune tolerance, a complete reversal of correct science.

Studies of traditional populations show their microbiomes are vastly different from those in industrialized nations. This suggests that what is considered a 'healthy' American microbiome might actually be a perturbed state, silently predisposing individuals to chronic inflammatory and metabolic diseases due to factors like antibiotics and diet.

Our immune systems evolved to mount robust inflammatory responses against acute threats like infections and traumas. In the modern world, which lacks these constant threats, this same sensitivity causes our bodies to overreact to environmental triggers. This evolutionary mismatch creates the chronic, low-level inflammation that drives modern diseases.

The gut lining is a major interface with the outside world populated by immune cells. These cells learn to distinguish harmless food from threats. If the gut lining is damaged, immune cells may misinterpret foods as threats, leading to allergies or sensitivities.

The American Academy of Pediatrics, operating on the precautionary principle, advised parents to delay introducing allergenic foods. This lack of early exposure prevented immune systems from developing tolerance, directly leading to a massive increase in food allergies and creating a disastrous feedback loop.