Modern life in all its cleanliness—clean buildings, sanitizer, antibacterial everything and a “don’t touch that” attitude—is thought to be contributing to the increased prevalence of allergic and autoimmune diseases found in developed countries. (This concept is known as the hygiene hypothesis.) Contrast this with developing countries where children still play in the dirt, antibacterial soap is reserved for medical use, and allergies and autoimmune disease occur much less frequently. Alzheimer’s can now be added to the list of conditions linked with living in industrialized countries, according to a new study published in the journal Evolution, Medicine, and Public Health.

The study looked at data from 192 countries and found that urbanized countries have higher rates of Alzheimer’s, irrespective of life expectancy. “Exposure to microorganisms is critical for the regulation of the immune system,” they stated. Inflammation, which is a function of the immune system, plays a role in Alzheimer’s disease. When the immune system is not presented with microbes early in life, it does not learn how to respond appropriately. The result is an increase in inflammation.

The link between Alzheimer’s and increased hygiene does not surprise me. Inflammation is involved in most, if not all, chronic disease. I think we will start to see more conditions that are linked to a lack of proper immune development during childhood. This is closely tied to gut balance, as the microbes in our guts are directly in contact with up to 80 percent of the immune system. I’ll be interested to see how this research unfolds. I’ll keep you posted.