Our gut evolved in contact with soil

Children eat soil. This desire appears to be embedded in the genetic make-up of humans. We got it through evolution, just like multiple animal species that share this habit. It is a common belief that the biological function of eating soil is that we need microbes naturally present there. However, the bacteria in soil show little similarity to the ones in our gut. It is not the microbes in soil which is important, but something else. So what is it?

Our large intestine is a vital organ

Soil contains substances which are needed by the body to maintain and stabilize a healthy microbial ecosystem inside the gut, especially in our large intestine (colon). It is home to more than a thousand billion microbes, totally outnumbering human host cells. Not only is our large intestine the main site where a varied and healthy gut microbial community (microbiota) interacts with our body in multiple ways of major importance for our health and well-being, but it is also the largest immunological organ in the body. Immensely important is that a healthy gut microbiota exerts a strong influence on the innate immune system which represents our first line of defence against all infectious microorganisms (virus, bacteria, fungi, eukaryotic parasites). It is mobilized immediately in response to an infection and is particularly relevant in cases where it takes a long time to develop a vaccine against new and unknown microbes.

Today’s modern lifestyle, with processed foods and sterile environments, disconnects us from the natural environment which has formed us throughout our evolutionary history, especially our contact with soil. Without such natural challenges, our gut microbiota loses ability to interact with our body in a beneficial way. An imbalance of the microbial ecosystem inside the gut – gut dysbiosis – is a root cause of multiple health problems.

Soil or no soil

The lifestyle in modern societies has disrupted our natural interactions with microbes, plants, animals, and soil. Over decades, everything that has been seen as dangerous (microbes) or without nutritional value has deliberately been removed, especially the natural stimuli from the environment (soil, domestic animals, etc.) as well as from our diets. Instead, excessive or misunderstood hygiene practices are common, and we have become exposed to antibiotics, disinfectants, herbicides, etc. The result is that we have become disconnected from the natural environment which has formed us throughout our evolutionary history, especially when it comes to our contact with soil.
Without such natural challenges, our gut microbiota loses the ability to interact with our body in a beneficial way. Imbalances of the microbial ecosystem inside the gut – gut dysbiosis – are not only detrimental to gut health, but contribute to “lifestyle diseases” like obesity, inflammatory disorders, asthma, allergy, autism, etc. as well as untreatable gastroenterological conditions like IBS (Irritable Bowel Syndrome) often leading to chronic fatigue (ME), just to mention a few. The many lifestyle diseases in our modern societies attest that our immune system is not capable of distinguishing between real threats – pathogenic microbes and cancer – and imaginary dangers – pollen and allergens.

Gut dysbiosis

Gut dysbiosis is recognized to be a root-cause of multiple serious health problems, for example:

  • Asthma, allergy, autism
  • Overweight and obesity
  • Mental disorders, anxiety, depression
  • Diabetes
  • Colon cancer
  • Life-threatening diarrhea (Clostridium difficile)
  • Inflammatory bowel diseases (IBS, IBD, Crohns disease)
  • Chronic fatigue syndrome (CFS/ME)