Early Exposure To Germs Has Lasting Benefits 136
ananyo writes "Exposure to germs in childhood is thought to help strengthen the immune system and protect children from developing allergies and asthma, but the pathways by which this occurs have been unclear. Now, researchers have identified a mechanism in mice that may explain the role of exposure to microbes in the development of asthma and ulcerative colitis, a common form of inflammatory bowel disease. The researchers show that in mice, exposure to microbes in early life can reduce the body's inventory of invariant natural killer T (iNKT) cells, which help to fight infection but can also turn on the body, causing a range of disorders such as asthma or inflammatory bowel disease (abstract). The study supports the 'hygiene hypothesis,' which contends that such auto-immune diseases are more common in the developed world where the prevalence of antibiotics and antibacterials reduce children's exposure to microbes."
This explains it (Score:5, Funny)
All those bullies sticking my head in the toilet were just trying to help expose me to germs. I should send them a thank you note.
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Re:This explains it (Score:5, Insightful)
Close, Bruce (Score:4, Insightful)
What made (past tense) you stronger is the stuff that killed half of each generation of your ancestors' competition.
What doesn't kill you delays the inevitable, but if it doesn't keep you from reproducing it improves the quality of your children's mates and thus makes your grandchildren stronger.
Re:This explains it (Score:5, Funny)
What doesn't kill you makes you stronger. Right?
Ever since my lobotomy, I've been bench pressing 300 pounds!!
Re:This explains it (Score:5, Funny)
Ever since I had a lung removed I cut my smoking in half.
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Right?
Unless it leaves you with a painful chronic condition or disability.
Pessimism ho!
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No. What doesn't kill you makes you injured.
Expose rats to radiation for many generations and you end up with sickly, weak rats - not mutated überrats.
Torment a person mentally and you get a mentally ill person, not a badass.
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Don't you mean you're?
Of course it is (Score:5, Insightful)
Humanity (or human like creatures) survived for several hundred thousand years without modern medicine. If the body was not capable of developing defenses to disease we wouldn't still be here.
Re:Of course it is (Score:5, Insightful)
On the other hand, the average life span of human being was around 30 years in those early days at best. It is modern medicine and general quality of life that extends that to 70+ years.
Re:Of course it is (Score:5, Informative)
Typically these numbers include an extremely high infant mortality rate, without which the difference is significantly smaller.
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Typically these numbers include an extremely high infant mortality rate, without which the difference is significantly smaller.
Of course. But that doesn't mean that 0 year olds dying back then magically stopped being a problem. It merely points to a deficiency of describing a distribution with just its first moment, the mean.
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I believe a popular hypothesis was that older women go through menopause to focus on helping the community instead of raising their own children. However I don't know if the hypothesis includes an explanation as to why this is unique to humans.
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http://www.merckmanuals.com/home/womens_health_issues/biology_of_the_female_reproductive_system/female_internal_genital_organs.html?qt=&sc=&alt=
(In the boxed part How Many Eggs?)
>Only about 400 eggs are released during a woman's reproductive life, usually one during each menstrual cycle. Until released, an egg remains dormant in its follicle-suspended in the middle of a cell division. Thus, the egg is one of the longest-lived cells in the body. Because a dormant egg cannot perform the usual cellu
Re:Of course it is (Score:4, Insightful)
At least the benefit of helping kids with the grandchildren outweighs the benefit of having more children at that age. It is well known that genetic defects like Down Syndrome rise dramatically once a woman is past her mid- to late 30s.
You also have significantly rising mortality without medicine so as long as it's not pretty much ensured that you'll last for another 10+ years the high investment in a pregnancy isn't worth it any more.
Evolution is always right.
Re:Of course it is (Score:4, Informative)
That's more of a result than a cause. Most other mammals don't have a menopause.
Only a few: http://www.sciencedaily.com/releases/2010/07/100701103405.htm [sciencedaily.com]
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I believe a popular hypothesis was that older women go through menopause to focus on helping the community instead of raising their own children. However I don't know if the hypothesis includes an explanation as to why this is unique to humans
It's probably because humans are the species with the longest childhood. For most other species, the offspring matures relatively quickly and leaves the mother, freeing her to bear and raise another generation. But it takes an inordinate amount of time for human children to become independent - I think we are the only species where the duration of the fertility period for women is comparable to the time it takes for a child to become an adult. Mothers still have to care for older children while bearing and
Re:Of course it is (Score:4, Interesting)
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There doesn't need to be a specific advantage to menopause, there just needs to be no disadvantage.
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.[W]hy do human females go through menopause in their late forties? That's unique to humans among mammals (and elephants, which live 70 years in the wild).
You can discover something interesting if you do a bit of googling on the topic of menopause: Nearly everyone either claims that menopause is unique to humans, or it happens only in some species X and humans. But different writers mention different species Xs that share this feature with us.
Now, they can't all be right about this. Consider the reports on the recent study that found menopause in guppies. (Yes, really; google for "menopause guppies".) Others report menopause in other primates, e.g. g
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Both of you are right, so let's just say it's about balance. Let the body fight and adapt as much as it can, help it when it can't do it anymore.
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Which could have happened without this particular interaction. What's your point?
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Humanity (or human like creatures) survived for several hundred thousand years without modern medicine. If the body was not capable of developing defenses to disease we wouldn't still be here.
Main difference in modern life is that most of us live long enough to see our grand-children and usually our great-grand children - human like creatures 10,000+ years ago probably didn't.
It's a new thing to do, and we've been getting much better at it in the last 100 years. Dental hygiene seems to be a good thing overall. Not drinking toilet water, while mostly good, also seems to have some bad aspects like Polio (and, yes, we've found another way around _that_ one, but there are others...)
I sincerely hop
You underestimate our ancestors (Score:2)
Main difference in modern life is that most of us live long enough to see our grand-children and usually our great-grand children - human like creatures 10,000+ years ago probably didn't.
Ten thousand years ago, our ancestors were very much like us today. You'd have a hard time telling us apart assuming similar childhood environments.
As for grandchildren -- it doesn't take a long lifespan when girls are mothers at 15. And bear in mind that humans evolved menopause. It didn't just happen, it's a complex process that has evolutionary costs and so must have significant evolutionary benefits. Which means that our very distant ancestors must have lived until their 50s often enough to make a di
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The number I've heard kicked around forever is an "average" lifespan of 30 years in primitive society... some live to 100, but most do not.
We've got a lot of interesting diseases to work on curing today, things that simply would have made us dead in the past, now we hang around and suffer long enough for the medical community to classify our conditions and try to do something about them - they even succeed occasionally.
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Most Westerners eat garbage or severely unbalanced diets and it has a large effect on fertility, sperm mobility, and 'aging' effects.
Occam's Razor (Score:3)
The short lifetimes of our distant ancestors mostly came from accident and infectious disease -- and up until 60 or so, your odds against both actually improve the older you get. Maybe fewer of them made it to those ages, but once they got out of childhood a fair number did. After that, their teeth were more likely to give out before their hearts did or before cancer got them (etc.)
As for the aging effects of modern lifestyles, I think if you research it you'll find that a reasonably active modern America
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Active modern american? That's a laugh, how about we talk about the general population, you can't pick and choose your populations. Second, US'ians were never anything to be proud of, they've never really had healthy diets and westerners in general don't have rich balanced culinary diets, but the USian culture has very little experience with food in general since it's so young.
Re:"Occam's Razor" cliche is bad subject line (Score:2)
Please read the grandparent (Score:2)
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Sure they did. Don't let the 'life expectancy' numbers fool you. IF (and it was a big if) you survived past infancy, you would likely live a good while.
Re:Of course it is (Score:5, Interesting)
Not entirely true. Grains harvested in the Mesopotamian region for the past 20,000 years contain a fungus that produces potent antibiotics. This was discovered by analyzing those who drank beer (albeit over a paltry 8,000 years) and finding the residue in the bones. Once the source was traced back to the fungus, it was obvious that anyone eating grains in the Middle East since the advent of farming (20,000 years ago) will have had "modern medicine".
http://www.wired.com/wiredscience/2010/09/antibiotic-beer/ [wired.com]
Before then? Well, honey is another rich source of antibiotics. It's also a hygroscopic material, so applying it to burns will not only kill bacteria but will also reduce inflammation, build-ups of toxins, etc.
It's unclear when Neolithic man first developed brain surgery, but there's no question that he did and that patients survived.
So man has had a LOT of medical assistance for a very long time. Not as much as in modern times, true, but it wasn't zero. Not by a long way.
Dog licking (Score:1)
I thought doctors had dogs lick head wounds to cure them.
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That, and the invention of spears. To protect against infected woolly mammoths.
Not of course (Score:4, Insightful)
This isn't a question of if the body can defend itself, but if it is better to let it do so or not. For example you can also heal from a broken bone, however it is better to not have to. Near as we can tell it is all downsides, no upsides to breaking bones. When you are young there are usually little long term downsides (at least if it isn't major) but still no upsides.
What these studies indicate is that is not the case with illness. It is actually better to get sick at an early age than not to. It looks like it is even more of a matter than it helps develop your defenses, but that they may actually be more likely to turn against you if they aren't used.
That is not at all obvious, and rather interesting research.
Not exactly (Score:4, Insightful)
What these studies indicate is that is not the case with illness. It is actually better to get sick at an early age than not to.
s/sick/exposed to some bacteria/ There's a big difference between being exposed to common bacteria of the soil and animal digestive tracts and coming down with smallpox, meningitis, etc. From the articles I've read, the protective effect is seen with completely harmless bacteria, so there's no reason to claim benefits from exposure to pathogens. Especially when you consider that infant diarrhea accounted for the majority of that 50% infant mortality.
With some exceptions. If your lifetime chances of avoiding a pathogen are slim, it may be better to be esposed in infancy while getting lots of maternal antibodies with every meal, assuming that Mama also gets exposed often enough to maintain a high antibody titre. That process is why polio was less of a threat in the 17th century, where the stuff was in the water supply all over the world, than in the 20th where we were actually doing things that blocked routine fecal-oral transmission.
All in all, with pathogens I prefer vaccination where possible.
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Yep soil bacteria can even improve mood:
http://www.msnbc.msn.com/id/18082129/ns/health-livescience/t/soil-bacteria-can-boost-immune-system/ [msn.com]
And increase learning ability... in mice ;) http://www.scientificamerican.com/podcast/episode.cfm?id=soil-bacteria-might-increase-learni-10-05-24 [scientificamerican.com]
Many like the smell after rain which partly results from bacteria: http://en.wikipedia.org/wiki/Geosmin [wikipedia.org]
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"Of course" early exposure to germs reduces allergies and asthma?
And while humans managed not to go extinct without the benefits of modern medicine, we did suffer from extremely high infant mortality, mostly from disease. The primary reason our life expectancy is so much higher today is because infant mortality dominated the average in the past and dragged it way down. So maybe these results are not quite so obvious.
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there is a difference between surviving and thriving.
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True, but prior to the development of modern medicine average lifespan was a heck of a lot shorter.
In Rome life expectancy at birth was about 25.
http://www.utexas.edu/depts/classics/documents/Life.html [utexas.edu]
Maintaining population was a big deal. Women were married as soon as they hit puberty and were expected to be pregnant except when nursing. Few women made it to old age.
So yes humans can survive without modern medicine. But it isn't as nice.
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Humanity also survived a few hundred thousand years before the advent of nutrient-negative slop that impersonated food - the difference between now and the peak of [insert historical empire here] is that they built their immune systems on real food, not this pasteurised, boiled, microwaved, vacuum-packed, irradiated, freeze dried, left on a shelf for a year shite most of us have to put up with. The sooner more people realise this and adjust their diets accordingly, the sooner companies such as Monsanto and
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Eating meat is great for you given all of the other parameters that obtained before about 1700. But more for versatility of the ecological niche you could fit yourself into than any other reason.
Sorry (Score:1)
Finding this hard to swallow personally. I was born with pneumonia and had chronic infections early in life. In my 20s I am still plagued by allergies, asthma and generally poor health despite generally good habits as far as diet, exercise, and hygiene. I cringe when I think about what kind of state I'd be in if I didn't.
Re:Sorry (Score:5, Insightful)
Finding this hard to swallow personally. I was born with pneumonia and had chronic infections early in life. In my 20s I am still plagued by allergies, asthma and generally poor health despite generally good habits as far as diet, exercise, and hygiene. I cringe when I think about what kind of state I'd be in if I didn't.
The theory goes that it's too late for sloppy hygiene to help you much, now, but if you ate more dirt as a kid, you'd be healthier.
Most of my anecdotal observations in life tend tend to agree: life in a bubble isn't good for you, even if you never leave it.
Re:Sorry (Score:5, Funny)
Most of my anecdotal observations in life tend tend to agree: life in a bubble isn't good for you, even if you never leave it.
Ah, but the big questions remains unanswered: Does the basement count? Do Dorito bits count as dirt? Are keyboards a good source of antigens for the early immune system?
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Most of my anecdotal observations in life tend tend to agree: life in a bubble isn't good for you, even if you never leave it.
Ah, but the big questions remains unanswered: Does the basement count? Do Dorito bits count as dirt? Are keyboards a good source of antigens for the early immune system?
Better than nothing, I suspect, but there's a bit too much homo (self-sameness) in that form of homeopathy to help you if you ever leave the basement.
Re:Sorry (Score:5, Insightful)
Just a hypothesis (Score:5, Interesting)
It's a good one, but there are several competing theories out there too. One of the best I've seen is the correlation between acetaminophen use in children and the development of asthma in children [nytimes.com]. It just so happens that clean, microbe-adverse developed nations have much more access to acetaminophen than dirty, unsanitized third world countries....
This is not just a hypothesis. (Score:2)
No. It's no longer a hypothesis if you've found the underlying mechanism. This is now officially a theory.
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Why is it that every theory on the subject has to point to one cause? I find it much more likely that a number of factors combine to produce the effect. Acetaminophen use could be one, lack of germ exposure could be another. I think it's quite likely that children breast feeding less in developed nations contributes as well. Heck, the fact that we're able to save so many children that would die in infancy with third-world medicine means that the ones that do survive in those third-world countries will be st
So all my health problems now... (Score:3)
... are due to not eating enough dirt as a kid. Well, I tried, but you know what mothers are like.
Vaccinate early and often, and breast-feed (Score:2)
And breast-feed, which we already knew. Some immune components are transferred with that milk.
What it doesn't say is give up on sanitation, homogenization, etc. The other side of that would be a high infant mortality. We don't really want to be putting intense evolutionary selection pressure on our own kids.
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No it doesn't. This has nothing to do with infectious disease. The bacteria in question are thousands of species of soil bacteria.
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Also, I am dubious that our society is keeping its kids and their food so clean and so completely avoiding raw vegetables, which are reservoirs of soil bacteria, that children aren't being exposed to them once they can handle solid food.
I guess I'd be a counterexample... (Score:3, Interesting)
Re:I guess I'd be a counterexample... (Score:4, Insightful)
Statistically absurd (Score:2)
Glad this is finally being proven. (Score:3, Insightful)
All those nutcases throwing around how our produced-foods society is causing all these new illnesses.
Is it hell. It is because we are being stupidly over-clean.
Biology never evolved in a sterile laboratory, it evolved with constant bombardments of infection that helps the body calibrate sensitivity, in exactly the same way that your skins touch sensors adapt to air pressure, your eyes adapt to light and countless others. Why should it have been any different to the immune systems sensitivity?
In fact, there is a partial truth to the produced-foods part, and that is more of a case that the food is too clean rather than microbe-filled.
We have been taught that all possible microbes in food are terrible, but are they?
Only a few select sources of food are overly-infected with nasty things, specifically beef supplies (which are just horrible for you in general)
Most other things are completely safe eaten raw. That includes milk, which has been blasted as dangerous to drink raw, but actually aids people with autoimmune. (now if only there was an actual full-on study for it since the sporadic cases of it all around are promising)
Fact is, if there is any sort of food source infection, the odds of you even getting it are as likely as you getting madcow disease or some other rare illness from eating, simply due to all the safeguards we have in taking care of animals, tracking food all across the world, etc.
Overly-cooked foods are of course bad for you, since burned foods contain carcinogens. But good luck getting anyone off that, some people like their food charred a little. You'll never be able to stop the grill lovers either.
As a person with crohns, it pleases me more is being found out about the intestinal tract and how the immune system functions there.
There was a recent huge discovery on how the immune functions were expressed there to prevent it from attacking vital resources and nutrients.
As an illness that is claiming so many more people due to this clean-freakishness that has become of society in recent years, it is about time people start to realize that clean isn't all there is to being healthy.
Re:Glad this is finally being proven. (Score:5, Insightful)
Only a few select sources of food are overly-infected with nasty things, specifically beef supplies (which are just horrible for you in general)
Most other things are completely safe eaten raw. That includes milk
I hate to break it to you, but milk and beef comes from the same filthy animal.
Dirt (Score:3)
The study supports the 'hygiene hypothesis,' which contends that such auto-immune diseases are more common in the developed world where the prevalence of antibiotics and antibacterials reduce children's exposure to microbes."
Not to mention soap, bleach, clean water for washing, floor coverings, indoor heating and cooling, etc.
In the 11th century, Maimonides wrote about asthma -- in the children of the nobility of Spain, where they actually washed and generally kept house before the Christians reconquered the Iberian Peninsula and made handwashing (etc.) cause for you to be hauled off by the Inquisition. The children of the poor, on the other hand, had dirt floors and crawled around in the dirt with dogs, chickens, goats, etc.
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Yes, and in the 11th century about 50% of children died before attaining the age of 5.
George Carlin was right! (Score:3)
You mean George Carlin was right?
"Wouldn't want some guy goin to hell and be sick!" - George Carlin [youtube.com]
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Raw sewage! It strengthened our immune systems! We were tempered in raw shit.
I always figured... (Score:1)
Getting immune (Score:1)
soil to the wound (Score:2)
soil to the wound was a typical street recommendation 40 years ago on my street.
"Unclean. Un-Unclean..." (Score:3, Informative)
Am I the only one who gets a titch annoyed with people who carry antibac-hand-gel everywhere to use at the SLIGHTEST of exposure to the world? I'm not talking people who use it when going to the doc's or at the grocery store if they're touching meat and stuff, but every. damned. time they touch any-thing at all. They're not even germaphobic, it just seems the 'in-thing'. Every time I've used it, I feel like I've taken a dive into an six-foot deep alcohol pool, and it burns.
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Am I the only one who gets a titch annoyed with people who carry antibac-hand-gel everywhere to use at the SLIGHTEST of exposure to the world?
If that's annoying you, then...well, let me paraphrase your sig:
You want to know how to help those people? LEAVE THEM THE F*&K ALONE.
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Yea? Tell me that when their kids are raging sick because of their lack of exposure, go to school and give something to MY kid. He handles it well and doesn't get sick as often, but when he does, it hits hard because it has to be something BIG to get past his defenses. So yea, I'd live and let live if it wasn't a problem put on others, but it is.
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Only they did it in a diplomatic manner, instead of with snarky-attitude.
and right after
You want to know how to help your kids? LEAVE THEM THE F*&K ALONE. --George Carlin
This conversation didn't start in a diplomatic manner. Why insist it revert to boringness?
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I always cringe at the thought of the breeding ground that gel residue left on the hands provides.
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And it STINKS. I understand certain places want to make it policy to use it, ie., the little child-care drop off at the local grocery store here, but I hate it. Next time I'm gonna lie and say he's allergic.
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I was on chemo and had a suppressed immune system for a couple of years. I slathered both myself and my toddler with antibacterial sanitizer every time we went in public. I got lots of disapproving looks from people who I know thought I was "needlessly" using it, but better that than catching the flu or pneumonia which my body wouldn't have been able to fight off.
_Lots_ of people have compromised immune systems for one reason or another. Please keep that in mind the next time you see someone using that h
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Very true that. I didn't mean to offend, honestly. Perhaps I should have stated it better in saying that I've witnessed/overheard people talking about it as if it's an absolute necessity, even if they aren't critically ill. Ie., a pair of women discussing it at the lunch counter at my work, both of them discussing how they use it 10+ a day whenever they touch money, go to the park, eat out, etc. without any mention of "yes, we have (insert big, compromised health issue) so we need to be careful." I'm not on
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I do understand your point. I have a biochemistry background so I do understand antibiotic overuse is a problem. I didn't mean to "take you down a notch" so much alert you to the fact that there might be more to the story than you were thinking about.
Okay, sure (Score:2)
Assume this study is 100% true.
I'll still take auto-immune diseases over dysentery or pneumonia in children: the two biggest killers of children in the world. Caused by germs.
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Well, of course that's the thing.
While what doesn't kill you makes you stronger none of this gives you an assessment on whether or not a population is better off over their lives with this exposure or not.
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Dysentery and pneumonia kills (basically) only if not cured. Cure requires few antibiotics and week or two in bed, hardly a problem for a kid.
The research doesn't suggest that we should stop curing patients...
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Sometimes you just have to take a RISK. People die, that is how life works. The war on nature has to stop. There are reasonable measures and then there is the extreme we go today on all fronts from heath to environment. We are an animal like all the others just too "smart" for our own good.
Will humans evolve? nope. not anymore. we put an end to that. Every sickly human has to live and procreate until we run out of resources. When I get seriously ill, I will just die as I am supposed to or kill myself. Fu
Mother knows best (Score:1)
When I used to take my kids around to see their grandparents, they'd rush outside to play with the dog in the dirt. My mother used to just smile and say, "Dirt is an essential nutrient for toddlers."
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I think one of the reasons for this is the following: http://science.slashdot.org/story/12/02/23/1341200/academics-not-productive-enough-sack-em [slashdot.org]
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It always baffles me that scientists are doing expensive research on something obvious.
Because things that are "obvious" very often turn out to be wrong.
Of course, sometimes they turn out to be right, and then people criticize the researchers for testing something that "everyone knows". But when so many previous studies showed that something that "everyone knows" isn't actually true, it adds to the evidence that to know what's actually true, you need to do carefully-controlled scientific studies of everything, no matter how obvious it might be. Otherwise, some of those things that are "o
Home schooling (Score:2)
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They may receive more benefits by being out in nature and interacting with a variety of people at all ages.
"Guns, Germs, and Steel" . . . (Score:2)
. . . so throw in some exposure to Guns and Steel, and your children should be all set for life.
Note that in the case of Guns, polarity is important. Exposure to the wrong side of the Gun may have the exact opposite effect.
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Interesting implications (Score:3)
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I'm interested in whether this would apply for bacteria only or if it goes for viruses as well. You see, bowel disorders (specifically inflammatory bowel disease) are a lot more prevalent in children with autism than in children without. I'm probably going to be flamed to hell for this, but this study would suggest that there might yet be a possible link between vaccines and autism.
From my Wikipedia browsing, there may be an indirect link. However, there has been some success with intestinal parasites and inflammatory bowel disease. [wikipedia.org]
However the trick is in linking autism, to IBD, to the hygiene hypothesis, to vaccines. It's an interesting hypothesis, and worth investigating in my opinion. I would like to see a trial of helminthic therapy on autistic patients to see if there is any improvement.
IV Natural Killer T (Score:1)
funny... (Score:2)
My mother worried when I *didn't* come home caked in mud after playing out with my friends all day... saying that, I have never had a cold, flu, chest infection or anything. Never had a day off school or work through illness either.