Jul 06, 2021 20:00:00

'Keeping your home clean doesn't hurt your child's immunity,' researchers claim.

In recent years, the

number of people with allergic diseases has increased , because 'the cleanliness of modern homes has reduced the chances of being exposed to bacteria and viruses as a child, and the immunity was weakened.' Some people argue. In response, a research team at University College London (UCL) wrote in a paper published in the journal of Allergy and Clinical Immunology , 'Keeping your home clean will damage your child's immunity. No. '

Microbial exposures that establish immunoregulation are compatible with targeted hygiene --Journal of Allergy and Clinical Immunology
https://www.jacionline.org/article/S0091-6749 (21) 00811-3 / fulltext

Being clean and hygienic need not impair childhood immunity | UCL News --UCL – University College London
https://www.ucl.ac.uk/news/2021/jul/being-clean-and-hygienic-need-not-impair-childhood-immunity

The ' hygiene hypothesis ' is a hypothesis that exposure to various bacteria and viruses during infancy gives a person immunity and prevents subsequent allergic diseases. Based on this hypothesis, there is an idea that 'people who live in an environment that is too clean in their childhood and are not exposed to bacteria or viruses have an underdeveloped immune system and are more likely to develop allergic diseases later.'

Graham Luke , a professor of medical microbiology at UCL, points out that microorganisms that live in the human intestines, skin, and respiratory tract do play an important role in maintaining good health. 'We need to be exposed to beneficial microbes, primarily from mothers, other families and the natural environment, throughout our lives,' he said.

However, in recent years, the idea that 'touching microorganisms is good' has been pursued, and the idea that 'washing hands and keeping the house clean reduces the chances of being exposed to microorganisms and is not good for health'. It is said that it has appeared. So, in a new treatise, Luke's team coordinated the conflict between 'keeping clean to eliminate pathogens' and 'taking microorganisms into the body to regulate immunity and metabolism.' I investigated whether keeping my surroundings really clean would have a negative effect on my health.

The research team analyzed the microorganisms needed to maintain good health and the types of microorganisms that could be exposed in the house, strengthened immunity by means other than taking in microorganisms, and cleaned the house and allergies. We also investigated studies that investigated the association of sexual diseases. As a result, it claims that the following four points were found.

・ 1: Immunity is not strengthened even if exposed to microorganisms in the house
Many of the microbes found in modern homes in urban areas away from nature are not needed to strengthen immunity, but rather can release metabolites that are toxic to humans, causing sick building syndrome. ..

・ 2: There is no need to be infected with a 'pathogen' to strengthen immunity
To get immunity to a pathogen, you don't necessarily have to be infected with the pathogen itself, you can also get immunity by vaccination. Previous

studies have also suggested that vaccines against one disease may strengthen immunity against not only certain diseases but also other diseases.

・ 3: Naturally occurring microorganisms are important, not inside the house
According to the research team, microorganisms that are important for human health are not the types that exist in the house, but the types that exist in nature.

A study conducted in Finland reported that when forest soil and grass were introduced into the nursery garden to allow them to come into contact with nature, the bacterial flora in the child's body was diversified and immunity was strengthened. I have.

・ 4: Keeping the house clean does not increase allergic diseases
A 2002 study showed that 'infants with high levels of hygiene by the age of 15 months are more likely to develop expiratory wheezing and atopic eczema between the ages of 30 and 42 months.' Meanwhile, a 2015 study showed that home cleanliness was not associated with the risk of asthma or allergic disease. The research team points out that the reason for these contradictory results is that 'exposure to a type of cleaning agent may accelerate the development of allergic diseases.'

From these results, Luke argues that there is no such thing as 'too clean and unhealthy' and that hygiene must be maintained to prevent the transmission of dangerous pathogens. In addition, if you are concerned about the adverse effects of cleaning agents, you can reduce the harmful effects by focusing on the surface of your hands and skin, which are especially prone to infection routes of pathogens. 'By being exposed to mothers, families, the natural environment, vaccines, etc., we can input the microbes we need, which is consistent with wisely targeted hygiene and cleaning.' Mr. Luke said.