Maintaining cleanliness and good hygiene doesn't necessarily weaken a child's immune system.
In a groundbreaking study published in the Journal of Allergy and Clinical Immunology, researchers led by Emeritus Professor Graham Rook of UCL Infection & Immunity have debunked the theory that modern Western society is too hygienic, causing defective immune systems in children.
The study, with the DOI 10.1016/j.jaci.2021.05.008, proposes that exposure to our mothers, family members, the natural environment, and vaccines can provide all the necessary microbial inputs for health. Contrary to popular belief, the microorganisms found in a modern home are not necessarily those needed for immunity.
Organisms that populate our guts, skin, and airways play an important role in maintaining our health right into old age. Exposure to these microorganisms in early life is essential for the development of the immune and metabolic systems.
The study does not suggest that intelligently targeted hygiene or cleaning practices are in conflict with these exposures. Instead, it emphasises the need for targeted hygiene in the home to prevent the spread of infection while limiting direct exposure of children to cleaning agents.
The researchers point to four significant reasons that disprove the theory that Western 21st century society is too hygienic. Improved hygiene reduces infectious diseases, better nutrition strengthens the immune system, medical advances mitigate immune-related illnesses, and controlled exposure to microbes through vaccinations and environments maintains immune balance.
Recent research demonstrates that when epidemiologists find an association between cleaning the home and health problems such as allergies, this is often not caused by the removal of organisms, but rather by exposure to cleaning products that cause a type of damage that encourages the development of allergic responses.
The study does not support the theory that Western 21st century society is too hygienic, as it highlights that vaccines not only protect us from the infection they target, but they also strengthen our immune systems.
The study was not about vaccinology, food allergy, or the epithelial barrier hypothesis, as indicated by the titles of other related studies: "Vaccinology: time to change the paradigm?" published in The Lancet Infectious Diseases 2020, "Food allergy as a biological food quality control system." published in Cell 2021, and "Does the epithelial barrier hypothesis explain the increase in allergy, autoimmunity and other chronic conditions?" published in Nature Reviews Immunology 2021.
Concrete evidence shows that the microorganisms of the natural green environment are particularly important for our health. Therefore, while it is crucial to maintain cleanliness in our homes, it is equally important to ensure that our children are exposed to a diverse range of microorganisms, whether through contact with family members, the natural environment, or vaccinations.
In conclusion, the study challenges the notion that modern hygiene is not "too clean for our own good." Instead, it emphasises the importance of a balanced approach to hygiene, one that allows for the necessary exposure to microorganisms for a healthy immune system.
