It is a long established fact that people who grow up on farms are more hardy than those who grow up in cities. Their immune systems offer more protection from allergies, multiple schlerosis, asthma, and inflammatory bowel disease.
Squeaky clean children seem to be the ones who are susceptible to whatever germs are floating around at the time. Kids who play in the muck and mud seem to have a stronger immune system. It does not seem to make sense.
Scientists found that microbes in the "gut" control a rare part of the immune system. If these microbes are absent, the immune system attacks the lungs and intestines. If microbes are introduced, the immune cells retreat.
Mice raised in germ free laboratories were the animals studied. Scientists discovered that the "innards" of these mice were totally clean. At the same time, the immune response was like that of diseases like asthma.
Pregnant mice of the germ free variety were exposed to microbes that day before giving birth. The babies had fewer of the attacking immune cells even after they had grown to be adults.
Of course a baby cannot be covered with filth and be expected to thrive. Manure is not the best place to make a mud pie. However it does seem that a nice balance between getting dirty and being clean can be reached. It could also be that getting dirty makes a child happy and everyone knows that happy people are generally healthier people.
These are only studies of mice so far. We are not mice. But I have observed many happy, healthy people who got dirty when they were young. So get dirty! It is good for you.
The answer to last week's What Am I? is Stone Henge. Congratulations to those who guessed correctly.