Ever since the Hygiene Hypothesis was proposed in 1989 as the reason for burgeoning allergy in the modern world, more and more research tends to confirm this idea. By way of reminder: The Hygiene Hypothesis posits that modern man is “too clean” and, therefore, his idle immune system looks for “work,” and ends up causing allergic mischief.
One of the supporting observations: It seems that if pets are present before a child is born, the child is less likely to be pet-allergic than if the pets appear after the child has lived in the home for a while. A recently published childhood allergy study done at Detroit’s Henry Ford Hospital supports this view and adds new insight. This longitudinal study, initiated in 1987, has tracked 555 children to adulthood.
Sure enough, as investigators had suspected but never scientifically proved, the presence of a cat or dog prior to birth led to reduced cat or dog allergy later in life, as compared to introducing the animal after birth. The pet-specific allergic reduction was better for dog than cat by 61 percent to 37 percent. Of perhaps even greater interest was that pre-birth pets also led to a global reduction in all allergies.
The Henry Ford researchers feel this is because the gastrointestinal flora that is established early in life is healthier when pets are present. Healthy gut flora alter immune response, so as to promote tolerance to common allergens.