Westerners' gut microbes make them sick

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Researchers compared the intestinal microbes of healthy children in Burkina Faso with those of healthy Italian children and found that the African kids had significantly more bacteria associated with lean people and less bacteria associated with obese people.

Additionally, the researchers detected bacterial strains of Prevotella, Xylanibacter, and Treponema only in the children from Burkina Faso. These bacteria are excellent at breaking down fibrous foods and producing short-chain fatty acids that provide added energy. Studies have also shown that those same fatty acids help protect the intestines from inflammation, which could explain why inflammatory bowel disease is almost unheard of in African communities that eat high-fiber diets, Lionetti says.

The increased diversity of microbes in the gut also makes the body more resistant to intestinal pathogens while tempering the immune system's response to harmless molecules, leading to fewer allergies, Lionetti says. The group reports its findings online today in the Proceedings of the National Academy of Sciences.

ScienceNOW: Western Diet Tied to Intestinal Disease and Allergies

Photo: Grubs for Sale by Adam Jones, Ph.D. Creative Commons Attribution-ShareAlike 2.0 Generic license.


  1. Cause and effect. One would expect the flora to be different because they are eating an entirely different diet.

    Rather than being made fat and allergic by having the wrong flora, perhaps the flora are different because of eating too much sugar, starch, and processed food.

    1. Why change your lifestyle when you can just take a pill to take care any unwanted symptoms? It’s the American way!

      In all seriousness though, I do wonder if we Westerners have unintentionally eliminated our access to some of these pro-biotics. If your parents didn’t have any left, how could they pass them on to you? How do pro-biotics get passed on anyway (other than a colon-content transplant…)?

    2. Yes that’s totally true but scientists have already shown that if you take fat mouse and give its bacteria to newborn mice they’ll grow up fat and vice versa—unfortunately there’s this whole human rights thing that kind of bans experimenting on them so we’re limited to correlations and such until the evidence permits giving people a nice little pill with the skinny bacteria.

  2. ok nothing to do with the article but…
    In the photo, that red/orange bucket or tin or whatever… is that really necessary?

  3. Probiotics would just be microflaura found in whatever you happen to be eating. Cooking would kill most of them, so I’m going to go out on a limb and say these people eat a lot more raw food.

    But in all seriousness, let’s put these little bugs in a pill the way they do with acidophilus species. Because I am NOT about to eat a bucket of grubs.

    1. Seems like a diet including lots of ultra-fresh organic garden produce would introduce all kinds of microbes… and the occasional grub that you won’t even notice! My money is on the helpful microbes winning in an otherwise healthy(ish) gut. I walk around the garden with toast, nom-noming whatever is ripe. Washing is for veggies I didn’t grow.

      1. My money is on the helpful microbes winning in an otherwise healthy(ish) gut. I walk around the garden with toast, nom-noming whatever is ripe.

        Even if that’s true typically, and I don’t know, you certainly run the risk of catching something nasty from time to time. Even if the soil is quite clean, there’s stuff like Toxoplasma gondii if the neighbour’s cat (or a feral one) has gone potty on your carrot patch. In less-developed areas, of course, there’ll be a wider range — eg if the area is flooded or irrigated with river water which may have been contaminated upstream.

  4. Reminds me of this interesting article from NY Times:

    Dr. Khoruts decided his patient needed a transplant. But he didn’t give her a piece of someone else’s intestines, or a stomach, or any other organ. Instead, he gave her some of her husband’s bacteria.

    Dr. Khoruts mixed a small sample of her husband’s stool with saline solution and delivered it into her colon. Writing in the Journal of Clinical Gastroenterology last month, Dr. Khoruts and his colleagues reported that her diarrhea vanished in a day. Her Clostridium difficile infection disappeared as well and has not returned since.

    I wonder if everyone needs to start having pro-biotic injections up their bums…

  5. I suspect the orange can serves as a scoop, or unit of measure. I wonder why the “grubs” aren’t wriggling away. They look more like adult millipededs or something, as opposed to larvae.

    Agree with Unmutual. We need to get some of these Grade A microbes and feed them to our obese.

    1. Yes, but if you start at Burkina Faso, you have to go much farther west to get to Italy.

      It’s “west” all the way ’round.

  6. Osprey101 is right on the mark. Healthy input equals healthy internal ecology.

    That’s kind of like looking at two mountains, one of which has been strip-mined and is covered in toxic slag, and the other one has been left pristine in a national park.

    Obviously, the presence of deer on the pristine mountain is the determining factor here. Just put deer on the strip-mined mountain and everything will be fine…

  7. Our heavily sanitized and processed diet and our near- pathological fear of ALL bacteria- because all bacteria is equally dangerous, right?- would be the key differences here, I think.

    1. I didn’t know the Proceedings of the National Academy of Sciences was a bastion of pseudoscience. Thanks for cluing me in, Teufelsdroch.

      1. I can confirm PNAS is indeed one of the most respected journals out there. (I’d rank it on the tier below Nature and Science, as in top-of-its-field, but not top-of-science)

        Yes, I’m a chemist and my girlfriend’s a microbiologist. This is not only _not_ pseudoscience, it’s increasingly well-established science. I’d heard about similar results before, (and discussed them both at home and work quite a bit as well) so this doesn’t come as a surprise to me (or probably most microbiologists) at all.

        E.g. http://www.microbeworld.org/index.php?option=com_jlibrary&view=article&id=2287

        And to answer other commenters, no it’s not as simple as being our diet, which in turn changes the bacterial flora. The evidence is pointing towards both. Which is pretty typical of biology, really. And would also go a long way towards explaining why dieting often doesn’t work so well.

        Likewise, the link between intestinal flora and allergies has been pretty well-established over the last decade. These things are simply not at dispute. It’s the mechanisms and causal relationships that they’re trying to find out.

  8. Some question whether ingesting “probiotics” can really help, since you’re basically introducing aliens into your very complex and very personal gut ecology.

    I wonder if we don’t all have all the good bacteria we need, even if we’ve been eating crap for decades, just in very small numbers. And if changing our diets would bring those numbers back up.

  9. Also, everytime you go on antibiotics you go back to scratch? Unless you bother to rebuild your stomach bacteria store

    1. Also, everytime you go on antibiotics you go back to scratch?

      Usual courses of antibiotics aren’t that strong, most of the flora survives (though sometimes it’s thrown out of balance). Heavier courses do kill off too much of the flora and do cause problems.

  10. If the price for a healthy gut is sickle-cell anemia, I’ll keep my western bacteria thankyouverymuch.

    1. Ok. But you would reconsider if you lived in a country where malaria is prevalent? Sickle cells (basically compressed red blood cells) confer immunity to malaria.

    2. If the price for a healthy gut is sickle-cell anemia, I’ll keep my western bacteria thankyouverymuch.

      Sickle cell anemia is a genetic blood disorder and has nothing at all to do with diet.

  11. There was a paper in Nature from last year on obese and lean twins, and the relationship to the variation in the gut microbiome.

    Obesity is associated with phylum-level changes in the microbiota, reduced bacterial diversity and altered representation of bacterial genes and metabolic pathways.

    “A core gut microbiome in obese and lean twins”, Peter J. Turnbaugh, Micah Hamady et al, Nature 457, 480-484 (22 January 2009) link.

    Also worth reading is this more recent paper:

    “A human gut microbial gene catalogue established by metagenomic sequencing”, Junjie Qin, Ruiqiang Li et al, Nature 464, 59-65 (4 March 2010) link

    The numbers are staggering:

    It has been estimated that the microbes in our bodies collectively make up to 100 trillion cells, tenfold the number of human cells, and suggested that they encode 100-fold more unique genes than our own genome.

    The Turnbaugh and Qin papers highlight both the complexity and variation in the gut microbiome, even between twins. In my opinion, Lionetti is jumping the gun a bit in drawing his conclusions about the relative impacts on health of the Western and Burkinabè diets based on bacterial differences alone.

  12. Do they fry the insects before they eat them? If they do I am so giving up my diet of Big Macs for a diet of fried locusts, caterpillars and bushmeat.

    As a bonus Google says their otters are clawless.
    I know they can still bite your finger off if you grab the wrong end but Otter Bourguignon, yum.

  13. I read these and think… what can I do? I think I should eat more dirty things, force people to double dip in my salsa, share ice cream cones, share beverages through the same straw, make out a lot ( check :-P ), lick random things…

    Any other ideas?

  14. i think the proper study design would take 100 kids from burkina faso, transfer them to the US and see whether both health and enteric colonization change.

    just pointing out a difference or two, link it to stuff that “plays a role” in a desease and draw conclusions is simple datamining with little merit.

    maybe the kids are more healthy because they have to work? maybe some decent jurisdictional system causes sickness? passing bribes to cops is more healthy than taking pills?

    seriously – just data mining. do the same with shampoo residues in african kids’ hair, dirt under fingernails, use of sun lotion, whatever….

  15. I, for one, welcome our new microbial overlords.

    Seriously, this is probably the future, where we begin playing with all the weird things living inside our bodies. It’s enough to make me want to take a really long shower.

    1. what?! this is about fat and lean people and some possible clues about why obesity is taking over in countries like the US, UK & Italy. Oh, wait, you’re using an advanced form of irony? Your life-expectancy-at-birth stat is irrelevant. Even if your percentages are spot-on, they don’t mean anything. Italy has enormous amounts of cash, which translates into hospitals, medicine, welfare, pension etc. Burkina Faso does not.
      Are you a troll?

  16. Also note the veggies sitting on the ground (mostly stacked on something, but not far from the ground and blowing dust). They aren’t ever refrigerated. Far more likely to support microbial growth than our triple washed, waxed, pre-sliced, refrigerated/frozen, treated with anti-microbials (sodium benzoate, sodium metabisulfite, etc.), sometimes irradiated vegetables.

    so, we’re pretty much trying as hard as possible to keep new microbes out of our guts.

  17. Life expectancy:
    Burkina Faso 53
    USA. 78

    Wouldn’t it be possible to choose a better representative?

  18. I’m surprised no-one has thought out the implications of this; For one thing, this means that picking your nose and eating it is actually /healthy/.

    Admit it: You’re stunned by the breathtaking implications.

  19. Am I the only one concerned that they talk about Treponema like it’s a good bacterium? Treponema pallidum is syphilis, people, syphilis.

  20. “Westerners’ gut microbes make them sick” — woah that’s an awfully weighted statement…paging Kevin Trudeau

    What does a “healthy” Burkinabe child even mean?

    Good intestines and the ability to break down fibrous foods don’t compensate for a good all around diet, which even if a child is healthy in Burkina, is probably fairly malnourished compared to Italians.

    A diet based almost entirely on millet meal, and the off chance of having tomatoes, onion, and mangoes and low protein doesn’t mean they are ‘healthy’.

    Just in…

    Life in Burkina Tied to increased malaria

    Take that Africa! USA! USA!

  21. I just want to say: those grubs look delicious. I eat grubs and insects any chance I get, considering them to be a great source of low-cruelty protein. I am lucky to live in a country where I can, even if it’s rarely!

    Bugs – the food of the future!

  22. I’m just going to leave this here..
    “After just one day of switching from a plant-based diet to a high-fat-and-sugar diet, mice with human intestinal bacteria developed bacteria associated with obesity in humans, and soon became grossly obese (Science Translational Medicine, November 11, 2009).”

  23. Usually do not post anonymously, but …

    Speaking as one who has Crohn’s disease (an inflammatory bowel dsease) and who has a severe stricture, I have been advised by my consultant to eat a highly processed diet and not eat lots of high fibre. Contrarily, I eat lots of fresh fruit and veg, and nuts and oats, and… (etc). Anecdote is not data, but in combination with the drugs I am far better on this high fibre regime than on drugs and a highly processed diet.

  24. Sorry for the technical terminology, but, duhhhhhh!

    Furthermore, if those grubs taste like lobster-butter-ravioli, I’ll take 10lbs.

  25. My wife has been on about this gut ecology stuff for a few years and changed our families diet to encourage a healthy gut flora. I was a complete cynic, but as I’ve gone from overweight, headache prone, sickly and constantly exhausted to the complete opposite based on nothing but diet change I’m starting to wonder.

    It seems like processed foods, refined flours and sugar are all pretty toxic, whereas veges, fermented stuff and animal fats are great for you. Strangely my wife always got sick drinking milk, however changing to illegal black-market milk that’s full fat, completely unprocessed and unpasteurized she has no problems. Apparently processing the milk to make it ‘safe’ kills something in it that the gut needs to digest it.

    1. i like the idea that there is black-market milk.:) but wonder what the black-market cows look like.

  26. After a course of antiobiotics, if you are lucky and your appendix is healthy, you may be able to repopulate your good gut bacteria from your appendix:


    Never hurts to add good guys on a regular basis, as far as I’ve seen. (goodbelly juices, Attune brand probiotic chocolate (!! & also tasty) bars, fermented foods like saurkraut, etc)

    A friend, upon hearing of the NYTimes article, quipped he’d known this for ages, based on an outdoorsman background, because beavers apparently have a huge appendix, to replenish the gut flora needed to keep digesting wood chips.

  27. Enjoyed reading good points made in the article and by the commentators.

    Despite several disagreements, nowhere did anyone really resort to downright rudeness, and some of the arguments were sharp and funny. Probably attributable to a combination of the commentators and the moderators.

    Thank you for the information and the grins.

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