Burton Mail

Keep it clean please

- GRAHAM ROOK Professor of medical microbiolo­gy at UCL


Is keeping our house very clean likely to increase the risk of my children developing allergies and diseases?


Graham Rook, a professor of medical microbiolo­gy at UCL, recently led a study into the apparent conflict between the need for cleaning and hygiene to keep us free of pathogens, and the need for microbial inputs to set up our immune and metabolic systems. Here he explains what he discovered.

“Our immune systems evolved to destroy micro-organisms that cause infections (pathogens) and to kill our own cells only if they become cancerous.

“But in the modern world our immune systems often attack ‘forbidden targets’ such as harmless molecules in the air (allergens such as pollen), or our own healthy non-cancerous cells (autoimmune diseases, multiple sclerosis) or our gut contents (inflammato­ry bowel diseases and food allergies). “So there’s a failure of the control mechanisms that should stop the immune system from attacking these forbidden targets. “Developmen­t of these control mechanisms is largely driven by signals from harmless micro-organisms to which we’re exposed, including those that colonise our guts, airways and skin.

“Children need exposure to microorgan­isms from their mother (during delivery and breast-feeding) and from other family members.

“Also, exposing children to the micro-organisms of the natural environmen­t in gardens and farms activates the control mechanisms, probably explaining why ‘forbidden target’ diseases are less common in traditiona­l agricultur­al communitie­s.

“Our ancestors made homes with natural materials such as untreated timber, thatch and mud, so most microorgan­isms in their homes were also derived from the natural environmen­t. But modern homes are built with unnatural materials including biocide-treated timber and plasterboa­rd. Such modern homes, especially if damp and deteriorat­ing, contain unnatural communitie­s of micro-organisms that can be toxic.

“Therefore, cleaning the home, which is essential for hygiene and depleting pathogens, also removes potentiall­y toxic micro-organisms without reducing necessary contact with the mother or nature.

“Moreover, children don’t need to risk death from exposure to pathogens to strengthen their immune systems because live vaccines, in addition to protecting from the target organism, exert non-specific immune system strengthen­ing effects.

“However, we need to minimise the exposure of children to cleaning agents. When cleaning agents are breathed or swallowed they act as signals to the immune system that increase the likelihood of allergic responses to whatever’s present at the time of the exposure, such as food, pollen or whatever.

“So, cleaning the home is beneficial and will not increase allergies, if we minimise exposure of children to the cleaning agents, and maintain contacts with microorgan­isms from mother, family and the natural environmen­t. And vaccines contribute additional training inputs to the immune system.”

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 ??  ?? A clean home is a healthy home – so long as you don’t expose the kids to the cleaning materials
A clean home is a healthy home – so long as you don’t expose the kids to the cleaning materials
 ??  ?? Prof Graham Rook
Prof Graham Rook

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