Just a single gram of soil can contain anywhere between 100 million and 3 billion bacteria. These microorganisms play a vital role in breaking down organic matter into nutrients which can then be absorbed by plants. Unsurprisingly, the most fertile soils contain the highest levels of bacteria.

Science Indicates That Soil Bacteria Benefit All Life Forms – Not Just Plants

But, in recent years, more and more scientific studies are suggesting that these bacteria can benefit us as well as plants. A research paper at Stanford University went as far to suggest that there may be an evolutionary reason why some children seem so tempted to eat dirt, beyond just curiosity.

Science is finding evidence that Grandma is right – children who are allowed to get mucky are generally less likely to become ill.

One undisputed fact is that there has been a rise in autoimmune diseases, asthma and allergies in many developed, so-called ‘sterile’, countries (that is, countries with high levels of sanitation). Some attribute these trends to an underexposure to environmental factors, such as soil and the many bacteria found in it, which play a role in disease risk.

A study at Harvard University compared the susceptibility of mice raised in a sterile lab environment with those from the wild to asthma and colitis, both autoimmune diseases. There was a marked difference between the two which has led some scientists to conclude that it is important for mammal’s immune systems to be exposed to microbes rather than forever shielded from them.

Notably, adult mice raised in the lab which were then exposed to germs became no less susceptible to the diseases whereas the same exposure to young mice increased their resistance to the diseases toward that of the wild mice. This suggests that it is important that young mammals, presumably including children, have exposure to everyday bacteria and microbes at this early stage of their life.

Soil science is in its infancy but already shows potential to revolutionise healthcare

While soil biology is a relatively new science, and a lot remains to be understood about how this life in the ground all around us affects us all, evidence from these early studies suggests that these bacteria are more important to humans that has been previously thought.

Dirty hands and a big smile – this has to be more beneficial than watching TV

Of course, I’m not advocating mixing soil into your children’s cornflakes – a scientific study really isn’t necessary to prove the detrimental health effects of doing that – but having the kids help dig the vegetable garden, play outside and having picnics on the lawn can only be beneficial.