Researchers say microorganisms found in a modern home are, to a significant degree, not the ones that humans need for immunity.
Dirty Secret: Keeping Children Clean Won’t Harm Their Immunity To Disease, Says New Study
WASHINGTON — The theory that modern society is too clean, leading to defective immune systems in children, should be swept under the carpet, as per a new study by researchers at University College London and the London School of Hygiene and Tropical Medicine.
In medicine, the “hygiene hypothesis” states that early childhood exposure to particular microorganisms protects against allergic diseases by contributing to the development of the immune system.
However, there is a pervading view (public narrative) that Western 21st-century society is too hygienic, which means toddlers and children are likely to be less exposed to germs in early life and so become less resistant to allergies.
In this paper, researchers point to four significant reasons which, they say, disprove this theory and conclude humans are not “too clean for our own good.”
Graham Rook, the lead author and Emeritus Professor of Medical Microbiology (University College London Infection and Immunity), states that humans need exposure to beneficial microorganisms in order to maintain their health.
“Exposure to microorganisms in early life is essential for the ‘education’ of the immune and metabolic systems,” he said.
“Organisms that populate our guts, skin, and airways also play an important role in maintaining our health right into old age: so throughout life, we need exposure to these beneficial microorganisms, derived mostly from our mothers, other family members, and the natural environment.”
“But for more than 20 years, there has been a public narrative that hand and domestic hygiene practices, that are essential for stopping exposure to disease-causing pathogens, are also blocking exposure to the beneficial organisms.”
“In this paper, we set out to reconcile the apparent conflict between the need for cleaning and hygiene to keep us free of pathogens, and the need for microbial inputs to populate our guts and set up our immune and metabolic systems,” said the lead author.
In a review of the evidence, the researchers point to several factors in their study. They highlight that those microorganisms found in a modern home are, to a significant degree, not the ones that humans need for immunity.
The vaccines, in addition to protecting humans from the infection that they target, do a lot more to strengthen the immune systems. Therefore, the study concludes that humans do not need to risk death by being exposed to pathogens.
The findings also reveal concrete evidence that the microorganisms of the natural green environment are particularly important for a person’s health and that domestic cleaning and hygiene have no bearing on our exposure to the natural environment.
Lastly, the 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 of the lungs to cleaning products that cause a type of damage that encourages the development of allergic responses.
“So cleaning the home is good, and personal cleanliness is good, but, as explained in some detail in the paper, to prevent the spread of infection, it needs to be targeted to hands and surfaces most often involved in infection transmission. By targeting our cleaning practices, we also limit direct exposure of children to cleaning agents,” said Rook.
“Exposure to our mothers, family members, the natural environment, and vaccines can provide all the microbial inputs that we need. These exposures are not in conflict with intelligently targeted hygiene or cleaning.”
(With inputs from ANI)
(Edited by Anindita Ghosh and Nikita Nikhil)