Did you often play in dirt as a child? Turns out playing through the greenery or in a forest may have immense benefits to your immune system. We have myriads of bacteria and other types of microorganisms living on and inside us. Some enable us to take up nutrients, others help bolster our immune system. That’s why diverse microbiome is important.
According to a small new experiment, consistent exposure to greenery and soil may be enough to change a child’s immune system for the better.
For this study, daycare workers in Finland rolled out a lawn, planted forest undergrowth such as dwarf heather and blueberries, and allowed children to care for crops in planter boxes. Within the span of a month, the diversity of microbes in the guts and on the skin of the children appeared healthier than before.
Increased T-cells and Other Immune Markers
Compared to other city kids who play in standard urban daycares with yards of pavement, tile and gravel, 3-, 4-, and 5-year-olds at these greened-up daycare centres in Finland showed increased T-cells and other important immune markers in their blood within 28 days.
“We also found that the intestinal microbiota of children who received greenery was similar to the intestinal microbiota of children visiting the forest every day,” says environmental scientist Marja Roslund from the University of Helsinki.
The experiment in Finland is the first to explicitly manipulate a child’s urban environment and then test for changes in their micriobiome and, in turn, a child’s immune system.
While the findings don’t hold all the answers, they do support the idea that a change in environmental microbes can easily affect a well-established microbiome in children, giving their immune system a helping hand in the process.
The Biodiversity Hypothesis
An environment rich in living organisms can affect our immunity. Based on that hypothesis, a loss of biodiversity in urban areas could be at least partially responsible for the recent rise in immune-related illnesses (e.g. allergies).
“The results of this study support the biodiversity hypothesis and the concept that low biodiversity in the modern living environment may lead to an un-educated immune system and consequently increase the prevalence of immune-mediated diseases,” said the researchers.
The study compared the environmental microbes found in the yards of 10 different urban daycares looking after a total of 75 kids between the ages of 3 and 5.
Some of these daycares contained standard urban yards with concrete and gravel, others took kids out for daily nature time, and four had their yards updated with grass and forest undergrowth.
Over the proceeding 28 days, kids in these last four daycares were given time to play in their new backyard five times a week.
When researchers tested the microbiota of their skin and gut before and after the trial, they found improved results compared to the first group of kids that played in daycares with less greenery for the same amount of time.
Even in that short duration of the study, researchers found microbes on the skin and guts of children who regularly played in green spaces had increased in diversity – a feature which is tied to an overall healthier immune system.
Their results largely matched the second group of kids at daycares who had outings for daily nature time.
Among kids who got outside, playing in the dirt, the grass and among the trees, an increase in a microbe called gammaproteobacteria appeared to boost the skin’s immune defense, as well as increase helpful immune secretions in the blood and reduce the content of interleukin-17A, which is connected to immune-transmitted diseases.
“This supports the assumption that contact with nature prevents disorders in the immune system, such as autoimmune diseases and allergies,” says Sinkkonen.
The results aren’t conclusive and they will need to be verified among larger studies around the world. Still, the benefits of green spaces appear to go beyond our immune systems.
Let Children Get Dirty.
“It would be best if children could play in puddles and everyone could dig organic soil,” encourages environmental ecologist Aki Sinkkonen, also from the University of Helsinki.
“We could take our children out to nature five times a week to have an impact on microbes.”
The changes are simple, the harms low, and the potential benefits widespread.