Sumedha B S, Bangalore University
“Hygiene” is the practice used to prevent the spread of infections. The term “cleaning” refers to practices used, to remove soil/dirt to make any surface visibly and aesthetically clean by using products.
“Too clean for our own good”?
The ‘hygiene hypothesis’ states that early childhood exposure to germs (microorganisms) protects us against allergic diseases by contributing to the development of the immune system. Concerning this, there is a pervading idea that modern 21st century, western society is too clean in terms of domestic cleanliness. Thich means toddlers and children are not likely to be exposed to germs in early life so, this leads to defective immune systems or less resistance to allergies. It has been proposed that the faulty immune-regulation is a result of poor microbial inputs in modern cleaned homes.
Researchers at the London School of Hygiene & Tropical Medicine, disagree with this theory in their recent paper. Exposure to microorganisms in children is required for the ‘education’ of the immune system. Microbes present in our skin, gut, and airways also play an important part in maintaining one’s health. So, throughout life, exposure to these beneficial germs is necessary.
But, for about 20 years, personal and domestic hygiene practices have been taken seriously. It is required for reducing exposure to disease-causing pathogens. But, they lower the exposure to beneficial organisms. So, the conflict now is between the need for hygiene (to lower the risk of infection by pathogens), and the need for microbial inputs to develop the Immune system.
The Key Points Discussed by Researchers:
•The microbes in a modern home are, to a certain degree, are not those which are required for immunity.
•As we know, we do not need to risk severe diseases by being exposed to pathogens. Vaccinations protect us from the infection that they target. It can also strengthen our immune system.
•There is evidence that the microorganisms of the natural(green) environment are specifically required for our health. So, domestic cleaning and hygiene have nothing to do with exposure to the natural environment.
The products commonly used for cleaning may reduce exposure to the microbiota at home. Recent research showed that when epidemiologists tried to find a correlation between clean homes and health problems, they found that the cause was not being too clean. Health problems resulted due to the exposure of lungs to common cleaning products. This caused a type of damage that is strongly linked to the development of allergic responses. Recent studies suggest that this could also cause a TH2-adjuvant effect which prompts the immune system to produce an allergic response. Common cleaning/ disinfecting agents used are detergents and quaternary ammonium compounds. Exposure to these agents every day or repeated exposures was found to be significantly linked to asthma in adults. Especially when the detergents are used as sprays.
In conclusion, in early life, vaccinations, exposure to family, and the natural environment can offer all the microbial inputs the children need. These exposures have nothing to do with practicing domestic hygiene or cleaning. So, cleaning our homes intelligently, to maintain cleanliness is a good practice.
Also read: Genetic biobank: a repository for the prevention of SIDS
References:
- Rook, G. A. W., & Bloomfield, S. F. (2021). Microbial exposures that establish immunoregulation are compatible with targeted hygiene. Journal of Allergy and Clinical Immunology, 148(1), 33–39. https://doi.org/10.1016/j.jaci.2021.05.008
- Akdis, C. A. (2021). Does the epithelial barrier hypothesis explain the increase in allergy, autoimmunity and other chronic conditions? Nature Reviews Immunology. https://doi.org/10.1038/s41577-021-00538-7
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