New research suggests that ultra-clean environments (and those little alcoholic hand sanitizers) are bad for your child’s immune system.

A recent study at the Tufts Medical Centre in Boston says that the immune system at birth is like an unformatted computer; it needs to be instructed and the only way it gets that instruction is through being used and tested.

“(Dr. Joel V. Weinstock)… said that public health measures like cleaning up contaminated water and food have saved the lives of countless children, but they “also eliminated exposure to many organisms that are probably good for us.”

 “Children should be allowed to go barefoot in the dirt, play in the dirt, and not have to wash their hands when they come in to eat. Children who grow up on farms and are frequently exposed to worms and other organisms from farm animals are much less likely to develop allergies and autoimmune diseases.

Although my wife and I encourage hand washing before meals and after bathroom visits, we have always been a little skeptical of the value of an over-sanitized environment. (To our great shame, we apply the deeply unscientific “five-second” rule to food that gets dropped on the floor! You know the one: “If it’s been on the floor for less than five seconds it’s still okay to eat”)

Via Kottke