Last year, we wrote about the Hygiene Hypothesis and its predecessor, the Old Friends Hypothesis. While the details vary somewhat, both hypotheses suggest that the immune system relies on early exposure to germs in order to develop properly. The basic conclusion is that when infants and children lack exposure to germs, they are more likely to suffer from asthma and allergies, due to the immune system overreacting to common and harmless triggers.
The rate of allergies, asthma, and respiratory infections has tripled by some estimates. And at the same time, so has the level of cleanliness. The hygiene hypothesis proposed that infants and children weren’t being exposed to enough germs due to hyper-sanitation. And the old friends hypothesis expanded on this by suggesting that there were certain types of pathogens humans used to be exposed to which helped our immune systems learn. The increased rate of allergies may be because we no longer encounter those beneficial germs, perhaps due to spending less time in natural environments.
A new study out just yesterday may add a little more ammo to the argument that we are over-protecting children from germs.
A team of Swedish scientists looked at the habits of parents when their child dropped his or her pacifier. While some parents rinsed or boiled the pacifier before returning it to the child, other parents sucked on the pacifier to clean it instead. Guess which method lead to healthier children?
Infants whose parents sucked on the pacifier developed fewer allergies, had fewer signs of asthma, and lower rates of eczema.
The study was unable to determine whether the key factor was germs on the dropped pacifier, germs from the parents’ mouths, or something else. But it’s clear there’s a connection.
For example, researchers suggested that the types of parents who suck on pacifiers to clean them may also be less meticulous about disinfecting their homes. And in general, they may be more comfortable with exposing their children to dirt and germs.
Over the past few years, scientists have realized that microbes in the environment and on children’s skin play a large role in the development of allergies. For instance, babies delivered naturally have different bacteria in their system than babies born via C-sections. And one guess which babies are healthier?
Turns out that C-section babies have higher rates of hay fever, asthma, and food allergies!
These recent studies are giving conventional health advice a run for its money. While doctors and public health officials have told parents not to share food or utensils with their babies, it seems the benefits of exposure to good germs greatly outweighs the risk of transferring dangerous germs. And while C-section births are more controlled with less of a chance to pass on dangerous infections, healthy mothers would be better off delivering naturally.
Cleaning up cities, getting people to wash their hands, and reducing hospital infections are all triumphs of public health from the last century. But where infectious diseases have fallen, allergies and asthma have risen. Good advice about staying clean has now been taken to extremes. And for all the obsession in our modern world about cleanliness, it seems that over-sanitizing has been taking a deep toll on the health of our children.