My uncle has a saying: “Healthy kids get their pound of dirt every day.” (or some variation of that phrase). His point was that today’s society over-protects children from common and healthy pursuits – playing outside unsupervised, getting dirty, and exploring their world. The result, he suggests, is a generation (or several generations) of adults who are less healthy and overly sensitive to food and environmental allergies.
While he is a scientist, he’s not a physician or an allergy specialist, so take his observations with a grain of salt. However, I think his anecdotal observations have merit – kids who are not overly-shielded from normal environmental risks, tend to be healthier.
Consider the video below about “Why Hardly Anyone in Isreal is Allergic to Peanuts” as an example of how that plays out.
(That said, I have a daughter who suffers from seasonal allergies, and she grew up no less immersed in the dirt on the farm than her siblings, so this conclusion is only an observation, not a statement of fact – which is also noted in the video).