Mud hands may help reduce asthma rates

At daycare or at home, you hear it daily: "Not in the mud!" or "Wash your hands!" But imagine if we let go of that reflex a bit. What if, instead, we encouraged children to root around in the earth, get muddy fingers and run among the trees? In Finland, they have done just that, and with impressive results.

Since 2008, they have deliberately allowed children there to play more in nature, and that has led to a decrease in asthma patients. Whereas in the Netherlands the number of asthma patients continues to rise, from 400,000 people in 2000 to nearly 600,000 today, in Finland they saw the opposite happen. In Finland, between 2008 and 2018, the number of visitors to the emergency room with asthma dropped 62 percent. Children who are in daily contact with fungi, bacteria and other microorganisms from nature have the chance to build a stronger immune system.

The power of nature on the immune system

In Finland, nurseries have made their outdoor spaces greener. Where there used to be tiles and gravel, there was grass, shrubs and mini forests. Children were not only allowed to play in the earth, but also to tend small plants. The results? Within a month, the children had a stronger immune system. Researchers saw a marked increase in key immune cells in their blood and found that their gut flora became healthier. Their bodies learned to deal with a variety of bacteria and fungi. This is something children in a fossilized urban environment get much less of.

These findings are consistent with the "biodiversity hypothesis": the idea that an environment with many different microorganisms trains the immune system and protects against allergies and autoimmune diseases. In the Netherlands, we see just the opposite happening. Now we see that many people's natural defenses are weakening because of urbanization and lack of greenery.

It is important to note here that the biodiversity hypothesis suggests that exposure to various microorganisms can help the immune system develop. But that does not automatically mean that less hygiene or getting dirty more often will prevent asthma. In fact, asthma has a strong allergic component and is often actually exacerbated by certain environmental factors. The influence of microbes on the immune system is complex and varies from one individual to another.

Building a natural resistance

The Finnish researchers compared children from different types of nurseries. Some played mainly on paved playgrounds, others went into nature daily, and a third group was given a newly designed green playground. The children who regularly played outside in greenery developed more diverse skinand gut flora - a sign of a strong and healthy immune system. It is important to note, however, that hygiene does remain very important. A balance between exposure and protection is crucial for a well-functioning immune system.

And it's not just limited to physical benefits. Playing outside, especially in nature, also helps with mental health and the development of motor skills. Children who play more often in green spaces often develop a greater connection to nature. The latter is crucial, because children who feel connected to nature handle it more carefully later as adults.

What can we do?

Not everyone has daily access to a forest or a farm, but small adjustments can make a world of difference. Less paving, more grass. More trees and bushes on playgrounds. Let kids keep their shoes on inside so microbes come in with them. Encourage parents to let their children enjoy stomping in puddles, digging through soil and getting their hands dirty.

Researcher Aki Sinkkonen puts it aptly, "It would be best if all children could play in puddles and dig in organic soil." As educators and childcare professionals, we can play a key role in this. We can create an environment where children need not be afraid of getting dirty, but instead are encouraged to explore the world around them.

So the next time you see a child enthusiastically playing in the mud, let them have fun. They might not only build a sandcastle, but also a stronger immune system.