How Playing In The Dirt Might Prevent Alzheimer’s
I have a particular interest in certain types of research, and this study that was published recently really piqued my interest:
Hygiene and the world distribution of Alzheimer’s Disease
As I’ll discuss below, this is not an amazing study – it has several major limitations. But it’s interesting nonetheless.
Dirt is Important
The researchers in this study (all scientists from Cambridge University in the UK), have been trying to determine whether there is any link between modern hygiene standards and diseases like Alzheimers.
In this study, the researchers looked at countries around the world and tried to determine (by accounting and controlling for various other factors) whether fewer pathogens and higher sanitation might increase the risk of Alzheimers.
What they found is that exposure to microorganisms is inversely related to the risk of Alzheimers. In other words, if you live in more sanitary and hygienic conditions (and are therefore exposed to fewer germs), then your risk of Alzheimers is significantly higher than if you lived in a less sanitary place.
The theory is that modern hygiene standards – although beneficial in many ways (we rarely die of food poisoning any more) – are also harmful to the development of our immune systems. And various studies have found that higher levels of microbial diversity (a wider variety of germs) are correlated with fewer autoimmune diseases.
Alzheimers is a disease that is very similar to many autoimmune diseases, so it’s not surprising that it might share some of the same causes.
It Won’t Actually Prevent Alzheimer’s But It Might Help
The evidence isn’t great yet, but greater exposure to microorganisms might be more beneficial than we think.
This study is very interesting, but it’s only observational, and it’s pretty much impossible to control for the variety of factors that are different between a very “hygienic” country and a very “non-hygienic” country. For instance, higher levels of urbanization were also correlated with Alzheimer’s risk.
Weaknesses aside, the evidence in general is good that we, as humans, depend a lot on microorganisms, and our modern quest to rid ourselves of germs might have a lot of unintended consequences.