Microbes in ours our gut can have a huge impact on our health, but research shows that the organisms around us – the so-called natural environmental microbiome – can also have a large impact. This suggests that we should all spend much more time interacting with nature, both outdoors and indoors.
I was first introduced to this emerging field of science by Professor Gretchen Daily of Stanford University. She mentioned a Finnish research project that showed that allowing preschool children to play in a yard containing “dirt” from the forest floor had a significant positive effect on their gut microbiome. Seventy-nine adolescent children participated in the study, all living in urban environments and spending most of their day in various day care centers throughout Finland. The only difference between them was that these day care centers had three different types of outdoor spaces.
The first type was a fairly standard outdoor playground, consisting of concrete, gravel and some plastic mats. The second type was typically found in preschools that are already nature-oriented, with grass, dirt, and plantings for children to play on. These two elements served as a control against which a third experimental space could be compared, in which concrete and gravel were covered with fragments of the forest floor and soil from a local coniferous forest.
Children were encouraged to play in only one of three types of playgrounds each day for the 28 days of the experiment (note that some kindergartens have multiple playgrounds). Before and after play, the children’s skin and gut microbiota were measured using genetic sequencing of bacteria collected from skin swabs and stool samples, and changes in T cells and cytokines in their blood were checked. These cells and proteins play a key role in preventing autoimmune and autoimmune diseases; their level is often used as an indicator of the proper functioning of the immune system.
Remarkable results emerged. A gigantic raise in the diversity of microflora on the skin and intestines was observed in children playing in the experimental playground compared to children playing in urban and natural areas. Importantly, these were the “good” types of microbiota – those associated with health benefits. There was also a significant raise in immune markers in children, indicating that they had enhanced immunoregulatory pathways, indicating a reduced risk of immune-related diseases such as inflammatory bowel disease and rheumatoid arthritis.
The importance of this study cannot be overstated. This means that even short-term exposure to nature’s microbial diversity can dramatically change the diversity of microbiota on our skin and gut. Furthermore, it suggests that altered gut microbiota may modulate the functioning of our immune system.
A vigorous microbiome is created, not born
Everyone has the distinctive microbial community in the gut – a person’s ethnicity, the food they eat, antibiotic exploit, body size, and amount of exercise – all leave a clear imprint on the diversity of gut microbes. The role of these microbiota communities is significant. Our organs can only synthesize 11 of the 20 imperative amino acids we need, so the rest along with the 13 imperative vitamins are taken up and synthesized by our intestinal microorganisms.
These microbial communities not only assist our gut extract nutrients from food. Microbes also produce some of the most significant compounds for our health, including immunosuppressive, anticancer and anti-inflammatory drugs. They appear to be linked to the functioning of our immune system, central nervous system and related health effects, so much so that clear correlations have been found between specific gut microbiota – so-called “sick” microbiomes – and certain diseases. Diseases characterized by a distinctive gut microbial signature include irritable bowel syndrome, inflammatory bowel disease, celiac disease and colorectal cancer, as well as extraintestinal diseases such as obesity and type 2 diabetes.