Messy truth: getting dirty boosts kids' immunity

Photo: Getty Images
Photo: Getty Images Photo: Getty Images/iStockphoto

Good news for parents whose children love getting messy - a new study has found playing in dirt could help prevent developing immune related diseases later in life. 

Many little people love nothing more than digging in dirt or sand and a new study from Finland suggests they will be all the healthier for it and it may even reduce the risk of developing immune related diseases.

Immune related diseases such as eczema and asthma are on the rise, especially in urban areas. Up to one in five Australians will develop eczema and one in ten asthma. 

One theory behind the increase is that we keep our living spaces, such as the home, and ourselves too clean, reducing exposure to some microbial which are necessary for developing strong immunity. 

Urbanisation too is believed to play a role, by reducing the opportunity for children to be exposed to dirt and natural vegetation, while increased consumption of processed foods, antibiotic use and urban pollutants have also been found to impact microbial health. 

Researchers in Finland looked at the role nature-orientated play could have on boosting immunity. Published in the Science Advances journal, the study followed 75 children aged between three and five across ten daycare centres in the urban cities of Lahti and Tampere, which both have populations above 100,000. 

Researchers assessed the differences in the outdoor areas of the centres and the impact these had on the diversity of the childrens' microbial bacteria.Three centres had existing green areas and were used as the control, while a further four had their gravel based outdoor areas covered with forest floor and introduced planters and peat blocks for digging. 

Educators then guided children through nature based play, such as gardening and craft activities using natural materials and children were given set times for free play outdoors.

All of the children were fed the same meals and snacks and they were followed over 28 days to see if there were any changes in the bacteria of their skin.


Researchers found that providing children with opportunities for daily contact with dirt and plants improved may improve their health by boosting the immune system. The children from the modified play areas were found to have a greater diversity of bacteria at the end of the study - in some cases, they had up to a third more than before the study. 

Blood samples were also taken and increases in T cells, which regulate immune function and TGF-β1, which aid cell proliferation and the body's immune response were also seen. Researches said these findings indicated introducing a greater biodiversity to children could play a role in reducing the risk of developing immune related diseases.

Another recent study has also linked childhood asthma and food hypersensitivity to an increased risk of developing irritable bowel syndrome in adolescence. 

According to the Australian Childrens Education and Care Quality Authority outdoor experiences is important for childrens growth, development, learning and wellbeing. Sensory play within outdoor areas, such as touching sand or dirt, is also considered important for stimulating brain development. Other benefits include strengthening fine and gross motor skills and fostering curiosity.