A recent study conducted in Finland showed that children's play in dirt strengthens their immune system and protects them from certain allergies. Researchers investigated the possibility of strengthening immunity in children through play with grass and dirt in fresh air. They found that children who played in dirt had a lower number of pathogenic bacteria on their skin after a month, and the regulation of immune cells in their blood was higher than that of children playing on sandy and stony playgrounds in cities. The study also indicated that contact with bacteria present in dirt may help a child's immune system develop, enhancing its defenses and protecting it from immune disorders and the risk of developing certain allergies. In another study, conducted in Sweden and published in 2024, it was shown that children raised on farms or with animals have lower allergy levels compared to other children, and they have more beneficial bacteria in their intestines, which are considered important for the support of the immune system in the body. These studies support the ‘old friends’ hypothesis proposed by Professor Graham Rook in 2003, which states that contact with a diverse range of bacteria at a young age contributes to the development of beneficial bacteria in the gut, which play an important role in strengthening the immune system. Health experts recommend providing children with the opportunity to play outdoors and in dirt, provided that the play areas are free from toxic and harmful materials. At the same time, doctors warn that certain parasites and harmful substances in dirt may pose risks to health, so it is advisable to avoid their ingestion and inhalation.
