How keeping children too clean can wreck their immune systems
Children with pets or who grow up on farms are less likely to have allergiesAsthma, eczema, hay fever and diabetes being fuelled by indoor lifestyles
18:27 GMT, 22 March 2012
Today’s children may be too clean for their own good, research suggests.
Evidence is growing that dirt and germs can protect against disease – and that our indoor-based, ultra-clean lifestyles are bad for our health.
According to the hygiene hypothesis, asthma, eczema, hay fever and childhood diabetes are all being fuelled by childhoods in which youngsters rarely roll in the mud, splash in puddles or play with animals.
Evidence is growing that our indoor-based, ultra-clean lifestyles are bad for our health and could be fuelling problems like childhood diabetes
It is said that without exposure to dirt and germs early in life, the immune system doesn’t learn how to control its reaction to everyday invaders such as dust and pollen.
This can lead to it mis-firing later in life, leading to allergies and other illnesses.
Taking course after course of antibiotics may exacerbate the problem.
The latest evidence comes from American researchers who studied germ-free mice, bred in a bubble and kept in sterile cages and fed sterile food.
The lungs and bowels of the germ-free mice contained extra-large numbers of a type of immune cell blamed for asthma and bowel problems.
And when the germ-free mice developed asthma or bowel condition colitis, it was much more severe than usual, the journal Science reports.
Asthma, eczema, hay fever and childhood diabetes are all being fuelled by childhoods in which youngsters rarely roll in the mud, splash in puddles or play with animals
Finally, the Harvard Medical School researchers looked at what happened when the rodents were taken out of their sterile environment and put in bug-ridden cages with normal mice.
The mice that were moved as adults did not become any less susceptible to disease.
But the germ-free creatures moved and exposed to dirt and bugs in the first weeks of life became no sicker than those reared normally.
This suggests that there is a window of time in which exposure to bugs teaches the immune system to work properly.
Researcher Dr Richard Blumberg said: ‘These studies show the critical importance of proper immune conditioning by microbes during the earliest periods of life.’
He is now trying to pinpoint the bugs that provide protection.
Graham Rook, emeritus professor of microbiology at University College London, said: ‘The way forward is to work out how these bugs are doing it, so we can exploit them through new vaccines and drugs.’
However, he urged parents not to deliberately let hygiene standards slip in a bid to made their children healthier.
This is because skimping on cleanliness could let other, dangerous bugs take hold.
Professor Rook said: ‘It would be terribly dangerous to say to people, “Let’s relax hygiene and we’ll have less of these diseases”.’
The hygiene hypothesis was first proposed in 1989, when it was noted that hay fever is less common in children with older brothers and sisters. It was suggested that catching lots of bugs from siblings provided protection against allergies.
Others studies have shown that children with pets or who grow up on farms are less likely to have allergies.