In the US people have allergies to many things, the most common ones being pollen, dust mites, mold, wasps and bees, cats and dogs, industrial and household chemicals, and foods such as milk, nuts, and eggs. Growing up in Sri Lanka, I cannot remember anyone in my family or friends who had allergies, apart from a very few people who had asthma and thus had occasional breathing problems. No one seemed to have the need to avoid foods and plants, apart from varying degrees of lactose intolerance.
But after I came to the US, I found that many people, including my own daughters and the children of other Sri Lankan immigrants, have allergies to all manner of things suggesting, at least on an anecdotal level, that these are due to environmental factors. I used to wonder about what might be going on. So this article was interesting. They compared the types and numbers of bacteria living on the skin, guts, and homes of families living in the west with those living in very rural areas in the developing world.
The results were incredible. Like most of us in the Western world, the families had far fewer types of bacteria living in and on them when compared with people in traditional tribes in parts of the developing world. One hunter-gatherer community was found to not only have a higher diversity of bacteria, but only one in 1,500 suffered from an allergy – compared with one in three in the UK.
The article goes on to suggest that children in the west spend far too little time outdoors, and thus do not get exposed as infants and children to the many bacteria that can defend them against allergens.
As Horizon tracked the movements of the two families over 24 hours, it discovered that they spent on average 91% of their days indoors – a pattern reflected across the UK. As our lives become increasingly sedentary we miss out on the vast array of bacteria that lurk in our gardens and waft through the air.
So, arguably, the easiest thing for all of us to do to reduce our chances of becoming allergic is to go outside. Whether it is walking the dog or strolling to school, the evidence suggests that being outside and taking a good deep breath of fresh air is good for you.
One study has even found that if you have more plants and flowers around your house you are not only more likely to have a diverse array of bacteria on your skin, you are also less likely to be allergic.
So the best thing for us to do might be to encourage children to play a lot outside in the dirt.
So, George Carlin was right, after all.
Crimson Clupeidae,
Although I am a fan of Carlin, I am not getting the allusion. Can you please elaborate?
I think Crimson Clupeidae is referring to a bit in Carlin’s 1999 HBO special You Are All Diseased where he talks about germaphobes and swimming in the Hudson River and no one in his neighborhood getting polio when he was a child.
Interesting theory. My kids were raised in a household with a rotating menagerie of foster cats and dogs and spent time at a friend’s farm the whole time they were growing up…and have no allergies whatsoever. A lot of their friends, however, are allergic to pretty much everything.
As we are collecting anecdotal evidence: I grew up in a rather rural setting, and while I certainly spend quite a some time inside reading, I was out nearly each day when the weather allowed, including visiting stables and regularily comming home mud encrusted. As I grew up, I developed several allergies.
I’ve read about the connection between lifestyle and allergies before and dimly remember reading that the Japanese population does not seem to follow the pattern, it seems there’s more than one factor.
Mano,
George Carlin on germs….
Jeff
I’ve often wondered if this has anything to do with the eradication of hook worms, and probably other parasites. Hook worms have been found to have a calming effect on the immune system, that greatly reduces harmful allergy effects. Allergies the result of an over-zealous immune system.
Of course, it’s also possible that some people were born with severe allergies, but simply died of them in infancy.
@Dunc No. 8
That has long been my supposition, along with a longish list of other adolescent challenges we deal with in schools today.
There’s also the challenges of being a country of relatively recent diversely-sourced immigrants: many people encountering types of food not seen before in much quantity. I would guess that the genetic pool and available exo-food diversity would be smaller in Sri Lanka, meaning allergies to foods would already have been selected against.
In the majority-recent immigrant populations in the Americas and Aus/NZ, with greater variety of foods available and people from all over exposed to them, I’d expect more interactions.
Off the cuff, but it has some plausibility as a potential factor, no?
There’s a name for what our host describes: the hygiene hypothesis. It seems rather well-supported, and I’ve seen some discussions of what to get exposed to for keeping allergies from developing. Preventing allergies with The Country Life | BIO230
lpetrich beat me to it, but yes, this is known as the hygiene hypothesis.
I seem to recall one of the first major pieces of data for this came just after the German reunification, which gave doctors a large set of possible comparison tests. One of the tests compared the rates of childhood asthma between East and West Berlin and discovered that, completely contrary to what the researchers had expected, children growing up in the cleaner air of West Berlin had statistically significantly higher rates of asthma. Given that many of these children were from the same families separated by the Berlin Wall within the last couple of generations, the environment was one of the few major differentiating factors.
I’m wondering if it’s not also a result of more people surviving childhood.
A bit like all those people who tell me “ahhhh, I had the measles as a kid, too, and I’m still alive!”
Also, while some of the research is definitely cool (I think in Berlin they’re working on a literal bullshit-vaccination), I’m always annoyed by the context in which these discussions happen, which is usually a mixture of “look at the horrible crimes western parents are committing against their children! Obesity! Computer games!” and the romantization of poverty, because nobody seems to ask the question what those kids are doing outside (apart from the fact that there might be some climatic reasons why children in the UK spend more time indoors than children in more southern countries).
I think this article is somehow right. I know a few people who are so keen on keeping their children away from bacteria and they are the ones who goes in and out the hospital. Our body has its natural antibodies which helps stave off foreign bodies and with us not exposed to these types will cause our immune system to eventually shut down and not function naturally.