The science on dirt and your child's immune system

Should you let your kids get dirty!?

Today, many parents are encouraged to keep things clean – wiped surfaces, sanitised hands, and tidy clothes. But this is quite a shift from those of us who grew up hearing that – a little dirt won’t hurt, in fact, it’s good for you. Perhaps, like many old expressions, there’s some magic in those dirty fingernails and muddy knees.

A world beneath our feet

It’s estimated that 1 gram of soil may contain up to 10 billion microorganisms with possibly thousands of different species.¹These microorganisms play a vital role in developing your immune system, particularly during early childhood when the immune system is still learning. Exposure to natural environments and the diverse microbes within them enriches the microbiome, promoting immune balance and providing protection against allergies and inflammatory disorders later in life.² So the more time children spend in biodiverse outdoor environments, the more likely they are to develop a healthy, balanced immune system.

What the science says

A ground-breaking Finnish study,³ tested this concept in a real-world setting. Researchers looked at several day care settings and added forest floor materials to urban day care outdoor areas. This included forest soil, moss, and sod to introduce more diverse bacterial communities to the soil. Children were encouraged to play in these natural areas for around 90 minutes daily over a period of four weeks, and the results were interesting.

Skin microbiome diversity increased – Children who played in the modified outdoor areas developed more diverse skin microbiomes, which became more like the skin of children in nature-based kindergartens.

Gut microbiome diversity improved – Children within the intervention group showed increased diversity of beneficial gut bacteria, including Ruminococcaceae, which produce anti-inflammatory compounds.

Immune function markers shifted – The children showed an increase in regulatory T-cells and anti-inflammatory cytokines and a decrease in pro-inflammatory cytokines.

In only one month, the children’s immune profiles began to resemble those of kids who attend nature-based kindergartens. This shows just how vital it is for children to access natural areas to play.

How playtime supports mental health

Time spent outdoors playing, especially unstructured play within a sensory-rich environment, has been linked to improved focus, reduced stress, and better emotional regulation in children. Interestingly, one microbe found in soil, known as Mycobacterium vaccae, has shown that subjects exposed to it exhibited less anxiety and better cognitive function. More research is needed, but early results indicate that this friendly bacteria could contribute to mood stability and resilience.⁴

Dirt isn’t dangerous!

For so long, we’ve been taught to fear germs, and at times for good reason. But could an over-sanitised lifestyle lead to immune dysregulation? Over the years, many researchers have interpreted that an over-sanitised environment and excessive cleanliness have led to an increase in immune disorders and increased rates of allergies. In some circumstances, a high level of sanitation and cleanliness is essential, such as in hospitals. Still, early exposure to beneficial microorganisms might protect the immune system and train the developing immune system to protect itself.⁵

Let them get dirty 🌱

In a world where hand sanitisers and antibacterial sprays are the norm, it’s easy to forget that a little mess is not only natural but necessary and often a lot of fun! Allowing children to reconnect with nature through gardening, messy play, and simply exploring nature can support their immune system, build resilience, and bring so much joy! Dirt should not be feared and could, in fact, be one of nature’s best medicines.

Tips for embracing the dirt with children

Give children the opportunity to embrace nature through gardening, mud kitchens, and nature treasure hunts. Encourage your child to engage with the natural world with all their senses.
Make sure children have designated outdoor wear. This will allow for easier clean-up and, of course, help you feel less precious about their lovely outfits, which are not intended for muddy stains.
Encourage cleanliness and handwashing with gentle natural soaps, avoiding harsh antibacterial products unless necessary.
Visit your favourite green spaces, such as woodlands, meadows, or a wild park. Not only will this boost their microbial exposure, but it also offers a sensory-rich environment and will boost their wellbeing.
Support their microbiome through their diet, ensuring they have a variety of plant foods and a daily probiotic.

For more ways to support your and your family’s immune systems, check out these articles –

Any questions? Contact one of our Nutritional Therapists via live chat, weekdays from 8 am to 8 pm.