Dirt can be good for children, say scientists

[AlaskaDenise]

Children should be allowed to get dirty, according to scientists who have found being too clean can impair the skin's ability to heal.

Normal bacteria living on the skin trigger a pathway that helps prevent inflammation when we get hurt, the US team discovered.

The bugs dampen down overactive immune responses that can cause cuts and grazes to swell, they say.

Their work is published in the online edition of Nature Medicine.

Experts said the findings provided an explanation for the "hygiene hypothesis", which holds that exposure to germs during early childhood primes the body against allergies.

Many believe our obsession with cleanliness is to blame for the recent boom in allergies in developed countries.

'Good' bacteria

Researchers from the School of Medicine at University of California, San Diego, found a common bacterial species, known as Staphylococci, blocked a vital step in a cascade of events that led to inflammation.

By studying mice and human cells, they found the harmless bacteria did this by making a molecule called lipoteichoic acid or LTA, which acted on keratinocytes - the main cell types found in the outer layer of the skin.

The LTA keeps the keratinocytes in check, stopping them from mounting an aggressive inflammatory response.

Head of the research Professor Richard Gallo said: "The exciting implication of the work is that it provides a molecular basis to understand the hygiene hypothesis and has uncovered elements of the wound repair response that were previously unknown.

"This may help us devise new therapeutic approaches for inflammatory skin diseases."

The lobby group Parents Outloud said the work offered scientific support for its campaign to stop children being mollycoddled and over-sanitised.

A spokeswoman for Allergy UK said there was a growing body of evidence that exposure to germs was a good thing.

But she said more research was needed.

"Rates of allergy have tripled in the UK in the last decade. One in three people now has some kind of allergy.

"Some of this might be that people are better informed. But a lot of it is genetic as well as down to our environment," she said.

http://news.bbc.co.uk/2/hi/health/8373690.stm

 

[AlaskaDenise]

Re: Dirt can be good for children, say scientists

I wonder if these bacteria also stop inflammation elsewhere?

.

 

[Snicklefritz]

Re: Dirt can be good for children, say scientists

I admit to not understanding the quote below. But, it seems in opposition to the original post. I'm confused...or it's too late, or too early

From The Lancet

Role of lipoteichoic acid in infection and inflammation

Original TextIsaac Ginsburg a

Summary
Lipoteichoic acid (LTA) is a surface-associated adhesion amphiphile from Gram-positive bacteria and regulator of autolytic wall enzymes (muramidases). It is released from the bacterial cells mainly after bacteriolysis induced by lysozyme, cationic peptides from leucocytes, or beta-lactam antibiotics. It binds to target cells either non-specifically, to membrane phospholipids, or specifically, to CD14 and to Toll-like receptors. LTA bound to targets can interact with circulating antibodies and activate the complement cascade to induce a passive immune kill phenomenon. It also triggers the release from neutrophils and macrophages of reactive oxygen and nitrogen species, acid hydrolases, highly cationic proteinases, bactericidal cationic peptides, growth factors, and cytotoxic cytokines, which may act in synergy to amplify cell damage. Thus, LTA shares with endotoxin (lipopolysaccharide) many of its pathogenetic properties. In animal studies, LTA has induced arthritis, nephritis, uveitis, encephalomyelitis, meningeal inflammation, and periodontal lesions, and also triggered cascades resulting in septic shock and multiorgan failure. Binding of LTA to targets can be inhibited by antibodies, phospholipids, and specific antibodies to CD14 and Toll, and in vitro its release can be inhibited by non-bacteriolytic antibiotics and by polysulphates such as heparin, which probably interfere with the activation of autolysis. From all this evidence, LTA can be considered a virulence factor that has an important role in infections and in postinfectious sequelae caused by Gram-positive bacteria. The future development of effective antibacteriolytic drugs and multidrug strategies to attenuate LTA-induced secretion of proinflammatory agonists is of great importance to combat septic shock and multiorgan failure caused by Gram-positive bacteria.

http://www.thelancet.com/journals/laninf/article/PIIS1473-3099(02)00226-8/fulltext#article_upsell

 

[Twall]

Re: Dirt can be good for children, say scientists

I'm also a firm believer of this concept, a little natural occurring dirt grim and germs are good for us.as a kid i played around in a old clay pit.which had became a small local dump and was home to all types of wild life. I spent a lot of time out doors doing all things forbidden from poking dead animals to drinking water from the local streams.I started working while still in school,around the age of twelve, for a local poultry dealer.we would normally remove the birds from healthy modern chicken houses and restock the house at a later date. we often handled from 6,000 to 20,000 live birds a day. on a rare occasion we would get and emergency call where somebody had a building collapse from snow loading on the roof or a fire. Yes, i crawled through the chicken crap as a kid to recover the live birds.even milked and feed the cows, swam in flood waters, raised a pet raccoon and a pair of foxes in the city and the coolest pet of all was Sam, a single pet pigeon that would fly along with us on the way to school every day.My mother hated the pet snakes we had,along with all the hundreds of caged mice we breed and raised to feed them.

I was never really sick, until i moved to Egypt, in my mid thirty's about seventeen years ago.most likely do to my lack of exposure to the local dirty elements.

my wife and both kids seem to get sick more often and sicker then i do to this day.I suspect its from moms genetic contribution as she has constant sniffles (shes basically Turkish/Egyptian) coupled with my exposure to all things in America when i was child.

my wife and i still today,"fight argue"! about her urge to force the kids every five minutes to wash themselves after they touch our dog or set foot out side or kill a fly of mosquito, i tell her all the time they need exposure to produce some degree of natural levels of immunities in their bodies.

we eat really healthy, lots of fresh vegetables,make bread,fresh cakes and cookies all types of salads chicken fish and some meat,plenty of dairy fresh fruit juices and lots of garlic and spicy hot peppers, honey and citrus. we make and can salsa as a base for use with pasta dishes and fresh pizza and preserve our own jelly's,pickles and we even roast then make our own fresh peanut butter.

we do these type things as a family, while we spend the time talking together honestly about anything.In this part of the world a man would traditionally not be involved in taking care of anything within the home including preparing a hot drink,any food or a meal and or cleaning their own bathrooms.

 

[AlaskaDenise]

Re: Dirt can be good for children, say scientists

Snick:

Interesting article. I need to reread it several times and hit the books to figure this out. Perhaps the location of the pathogens, i.e., skin vs elsewhere, which makes the difference. Since the skin must constantly deal with germs, it would make sense that it's immune response would be different.

Twall:

There has been a lot written about the benefits of good dirt and how children raised on farms (with livestock) are healthier. One source writes:

The innate immune system and commensal bacteria

The human large intestine (colon) contains an enormous (~10-14) population of microorganisms. (Our bodies consist of only ~10-13 cells!) Most of the species live there perfectly harmlessly; that is, they are commensals. Some are actually beneficial, e.g.,

?by synthesizing vitamins;
?by digesting polysaccharides for which we have no enzymes (providing an estimated 10% of the calories we acquire from our food);
?by stimulating the development of the adaptive immune system, including Th1 helper cells (which then inhibit Th2 helper cells which may provide protection against allergies like asthma). [Link]
Despite the name ("pathogen-associated"), PAMPs are found on all these nonpathogenic bacteria as well.

It turns out that not only do these bacteria not trigger inflammation, but their presence is needed (at least in mice) to maintain a healthy colon.

?Mice that are raised in a germfree environment [Link] or are treated with antibiotics to clean all the bacteria out of their colon are unhealthy and have G.I. tracts that are hypersensitive to injury. However, if they are given
◦LPS (from Gram-negative bacteria) or
◦lipoteichoic acid (from the peptidoglycan of Gram-positive bacteria)
in their drinking water, their colons resist injury.

?However, "knockout" mice that
◦lack TLR-2 or TLR-4 or
◦cannot signal through their TLRs [Link]
are not protected by such treatment.

These results
?suggest that a continuous low level of activity of the innate immune system is essential to health ? even in the absence of pathogens;

?explain why deliberating feeding harmless bacteria ("probiotics") has proved beneficial to some human patients with a diseased colon;

?provide another reason for avoiding the indiscriminate use of antibiotics (which kill harmless bacteria as easily as pathogenic ones).

This is part of a good online Biology course: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/W/Welcome.html


.

 

[ming]

Re: Dirt can be good for children, say scientists

I agtee, Twall. All the things our grannies told us are now proving to be true, and the doctors who scoffed at "old wives tales" & thought they knew it all have found out they don't !

 

[wetDirt]

Re: Dirt can be good for children, say scientists

It's good for more than just children....

wD

:applause: