" As it happens, the higher the hygiene standards in a country, the higher that nation’s incidence of allergies and autoimmune diseases. The more sterile a household is, the more its members will suffer from allergies and autoimmune diseases. Thirty years ago, about one person in ten had an allergy; today, that figure is one in three. "

― Giulia Enders , Gut: The Inside Story of Our Body’s Most Underrated Organ