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Science

Gut Bacteria Affect the Brain 162

Posted by Soulskill
from the colbert-was-right-all-along dept.
Rambo Tribble writes "John Cryan, a researcher at the University College Cork, explains the relationship between the bacteria in your gut and your brain. 'In a pioneering study, a Japanese research team showed that mice raised without any gut bacteria had an exaggerated physical response to stress, releasing more hormone than mice that had a full complement of bacteria. However, this effect could be reduced in bacteria-free mice by repopulating their gut with Bifidobacterium infantis, one of the major symbiotic bacteria found in the gut. Cryan’s team built on this finding, showing that this effect could be reproduced even in healthy mice.' It seems the flora in your intestines can influence brain development as well as aspects of health and nutrition, which in turn affect such things as hormones and neurotransmitters. 'His team tested the effects of two strains of bacteria, finding that one improved cognition in mice. His team is now embarking on human trials, to see if healthy volunteers can have their cognitive abilities enhanced or modulated by tweaking the gut microbiome.'"
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Gut Bacteria Affect the Brain

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  • by RichMan (8097) on Friday February 21, 2014 @04:56PM (#46306717)

    We are 90% bacteria. It is time we stopped viewing ourselves as a monlithic organism and started viewing ourselves as some sort of managed colony.
    http://www.npr.org/templates/s... [npr.org]

    "We think that there are 10 times more microbial cells on and in our bodies than there are human cells. That means that we're 90 percent microbial and 10 percent human. There's also an estimated 100 times more microbial genes than the genes in our human genome. So we're really a compendium [and] an amalgamation of human and microbial parts."

    • by SuricouRaven (1897204) on Friday February 21, 2014 @04:58PM (#46306735)

      We're more of a bacterial mass-transport vehicle.

    • by i kan reed (749298) on Friday February 21, 2014 @04:59PM (#46306745) Homepage Journal

      This is misleading, because our mass is still predominantly genetically human eukaryotic cells. Bacteria are so tiny that there are a greater number of them, but we're still mostly just human.

      • by Samantha Wright (1324923) on Friday February 21, 2014 @05:13PM (#46306867) Homepage Journal

        As someone who does this stuff for a living, I'd argue the contrary—that the weight ratio is misleading, because it's an exception. In terms of RNA and protein-coding genes, isoforms, homologues, and selection rates, in addition to more obvious things like number of cells, they vastly outstrip the core of the body. Think also of how much more time they've cumulatively had to evolve and swap genes!

        The best analogy for this, I think, is a *nix distro—the human genome is a monolithic kernel, and the bacteria are all the shell scripts and daemons that help manage it.

        • The best analogy for this, I think, is a *nix distro—the human genome is a monolithic kernel, and the bacteria are all the shell scripts and daemons that help manage it.

          It's funnier if you run it the other way.

        • by cold fjord (826450) on Friday February 21, 2014 @05:50PM (#46307221)

          ...the human genome is a monolithic kernel, and the bacteria are all the shell scripts and daemons that help manage it.

          So what you're telling me is essentially that the viability of myself and any offspring is going to depend on a massive collection of perl scripts. Lovely. I'm forked. :(

        • I agree, it's about the active parts, not the scaffolding. Just as you would judge a home more by its occupants than by the walls and furniture, at least if you were interested in behavior more than artifact and architecture.

    • Well, crap. I was taking an antibiotic this week. But not it's starting to sound like genocide.

  • Machines (Score:5, Funny)

    by i kan reed (749298) on Friday February 21, 2014 @04:58PM (#46306733) Homepage Journal

    I don't think I mind being an extraordinary complex machine functioning to protect the interests of very simple organisms incapable of thinking for themselves. But that might just be my bacterial overlords talking.

    • FILTHY HUMAN SHELL:

      We order you to procure more monosaccharides and disaccharides of appropriate molecular conformation.

      Or we shall consume you and find a superior performing shell.

    • It seems possible that guy bacteria affects nutrient absorption, and that affects brain activity. The studies so far have not focused on mechanisms of action, just showing that the effect does exist.

      For all we know, those poor mice had that constant, gnawing hunger that couldn't be satiated. And that's why they couldn't think clearly.
      • It seems possible that guy bacteria affects nutrient absorption, and that affects brain activity. The studies so far have not focused on mechanisms of action, just showing that the effect does exist. For all we know, those poor mice had that constant, gnawing hunger that couldn't be satiated. And that's why they couldn't think clearly.

        seems a little sexist to me. maybe more than 1/2 of all bacteria is female. :)

        • by Immerman (2627577)

          Actually, I've heard a rumor that 100% of bacteria are completely genderless. Bunch of freaks going around having sex just to tinker with their own DNA. At least they're not as bad as the slime molds with their five different genders, crawling around the forest floor in a giant colorful amoeba-like orgy for anyone to see. Shameful. ;-)

          • Point of fact, you'd be mistaken. Horizontal gene transfer does occur in the bacteria world, it's just not a necessary step for reproduction.

            • by Immerman (2627577)

              Where do you see an error? Yes horizontal gene transfer occurs, but it doesn't involve gender, and is humorously a
              > Bunch of freaks going around having sex just to tinker with their own DNA.
              I had initially used the term asexual, but I figured being "completely genderless" was more amusing and didn't run the risk of confusing the issue with the unrelated human sexual orientation of the same name. Especially when I go and say they have sex in the very next sentence.

              In point of fact not only is asexual se

  • Morality questions (Score:5, Interesting)

    by DoofusOfDeath (636671) on Friday February 21, 2014 @05:00PM (#46306761)

    I know I'm not the first person to think of this, but...

    The more external influences we see on brain function, the less sure I am of how appropriate it is to hold people responsible for their actions.

    For example, if child molestation is something one is predisposed to after being molested as a child, what's a just punishment if/when that person him/herself goes on to molest? Or, in this case, if ones gut bacteria makes on prone to certain behaviors, for example stress --> violence (not sure that's right, but just for the sake of discussion), should we hold every to persons equally accountable for having a violent reaction?

    • Well, if I were molested as a child, and I grew up with the impression that molesting a child was a good thing for me to do, hmm. I guess I'd molest a child? Except, as it stands, there are a lot of very mean people with tasers and shit that will beat me to death if I do that. So, maybe it seems like a good idea, but there are consequences?

      Holding someone accountable for their actions has more functions than "application of justice". Justice is something that's nice to think about, but it's really a

    • by danlip (737336) on Friday February 21, 2014 @05:20PM (#46306923)

      Independent of this, there is a moral question of "should we be punishing people?" The alternative is to focus on deterrence, rehabilitation, and protecting society. "Protecting society" could justify locking someone away for ever (if the justice system determines there is no chance of rehabilitation). "Rehabilitation" could include altering their microbiome if we figure out how, or it could just be psychological work. Punishment is government administered revenge - it may provide some deterrence, but it's not particularly good at it. But modern justice systems still focus almost entirely on punishment.

      • Punishment is easy to administer and audit - it pairs well with the concept of "Justice." Rehabilitation is a squishy concept, hard to measure, easy to accuse of uneven administration, favoritism, corruption.

        Even though "Justice" has little to do with making the future a better time / world a better place, those are the systems we have in place, and they seem to endure more because they are easy to explain and understand than because they are effective.

        • by Urza9814 (883915)

          Punishment is easy to administer and audit - it pairs well with the concept of "Justice." Rehabilitation is a squishy concept, hard to measure, easy to accuse of uneven administration, favoritism, corruption.

          Exactly. But if we can quantitatively measure the cause -- imbalance of gut bacteria or neural pathways or chemicals or whatever it happens to be -- then we can also determine if it has been resolved. We're a LONG way from having that capability, but perhaps someday....

          • My children (2 boys, 10 and 12) are "exceptional" - which used to have less nice sounding labels when I was in school.

            I struggled for a while with the concept when they were first diagnosed, but, in the end, I want to help them cope with the world the best they can as they are. If there was a magic pill I could give them that would forever "cure" them and make them "normal," I'd really hate to use it. That whole "as they are" concept is pretty squishy and ill defined, but I don't want to live in a "monocu

            • by cellocgw (617879)

              Yeah, well, misusing the word "exceptional" doesn't change the facts of your children's medical condition(s).
              And you should take a step back and consider just how incredibly selfish you sound when you claim you wouldn't give them a cure for their physical/mental defects. Did you ever stop to think how much fuller their lives would be if they could function somewhere in the normal range? Or to think what *they* would say if offered the chance?
              Maybe you should read "The Reason I Jump" for some prelimin

              • For a couple of decades, the majority of my peers called me alternately "Moron," "Idiot," "WTF is wrong with you," etc. I didn't like them doing that, but I really wouldn't have liked being made into a carbon copy of them. I was fortunate enough to be "in sync" with the academic testing regime of the day, so while most of my classmates called me "Moron," I was consistently turning in test scores that said otherwise, in spades.

                My kids aren't getting the test scores that I did, but they are having a less tr

                • by cellocgw (617879)

                  I didn't say "normal behavior." I said normal cognitive / physical ability. There's rather a world of difference (you insensitive clod).

                  • Well, the way my kids "behave," you'd think they could do better on those tests, "if they just applied themselves." "They're obviously really smart, they just don't talk like other kids their age do.." etc. There's a reason it's called a dis-ability, but, from a parent's ever optimistic perspective, they're "differently-abled" and I hope I can help them find a way to be themselves and also not get clobbered by the competitive world out there.

            • by Urza9814 (883915)

              Well, I agree with you there, but the discussion was about application to the criminal justice system. So these kinds of treatments would be much like existing psychological therapy techniques -- unless your children *kill someone* or something along those lines, nobody should force them to become "normal". Though I'd say they certainly shouldn't be prevented from doing so voluntarily either if they someday wanted to.

              • Well, depending on who is administering justice, my kids may well end up incarcerated some day. They're not violent, or harmful to others, or mean, or prone to unusual destruction of property or theft, but they don't follow verbal directions well, at all. Judging from all the Cops episodes ever produced, failing to follow the officer's direction, immediately, invariably leads to arrest... We've also been through a whole host of elementary schools, with principals that ranged from apathetic, to incompeten

    • Well, if someone suffers from a mental condition that makes them predisposed to molest children, then I would say they as a self-determining individual are less culpable. Note that this does NOT mean that they are any less of a danger to children (the kid's still fucked), so the question becomes what's the appropriate punishment/response. From the perspective of the victims, it doesn't make a difference what form of incarceration is imposed; but to the perpetrator it's a big difference.

      I think many people

      • by javelinco (652113)
        So, in this case, if they are unable to control their actions, then either we need to reprogram them or terminate them, correct? Why feel bad killing off a bad program?
        • by Urza9814 (883915)

          So, in this case, if they are unable to control their actions, then either we need to reprogram them or terminate them, correct? Why feel bad killing off a bad program?

          But it's not a bad program, that's the point. It's merely been given bad input. "Terminating the program" in this case would be like deleting Photoshop because it can't improve any of your photos -- when you've been leaving the lens cap on the whole time.

        • by Immerman (2627577)

          Or we could simply remove them from society, allowing them to continue to live in a controlled enviroment where they can't hurt anyone else. I'm thinking something like a zoo, except individuals are caged to prevent them from continuing to hurt others, rather than to help preserve their species.

    • by ceoyoyo (59147)

      The problem with the phrase "hold people responsible for their actions" is that many people seem to think it means "get revenge on people who we think wronged us." Modern criminal systems focus on rehabilitating criminals, not "punishing" them. Whether or not you're responsible for your actions only has bearing on whether or not you deserve retributive punishment. What you did and the chances of you doing it again are relevant to whether or not you can be allowed to run around unsupervised. Your gut mad

      • by Immerman (2627577)

        What country are you in? The US "justice" system certainly doesn't operate on any such principles. If it did we wouldn't sentence perpetrators of minor and victimless crimes to protracted immersion in a a population of hardened criminals, forcing them to become far more dangerous in the interest of self-preservation, and giving them the opportunity to learn many new criminal skills from experts in the field.

    • The more external influences we see on brain function, the less sure I am of how appropriate it is to hold people responsible for their actions.

      If you want to consider yourself a free individual, you have to accept responsibility for your own actions. In that sense it doesn't matter whether you are really acting out of free will or not. It's all about how you choose to see yourself. Personally, I don't see the attraction of thinking of myself as an automaton, but if I did then I certainly couldn't object if others (automaton or not) took steps to protect themselves from me, since I'm claiming to have no control over my effects on them.

      If you harm s

      • by Immerman (2627577)

        It goes even further than that - if you claim to be an automaton then the logical extension is that everyone else is as well, and they are thus not responsible for putting you though a meat-grinder for wearing mismatched socks, leaving you no grounds to object. Of course you will probably do so anyway, but that's okay, as an automaton you didn't have a choice and are thus not responsible for your hypocrisy.

        • if you claim to be an automaton then the logical extension is that everyone else is as well

          I'm not sure I can buy that argument in general. It's true if you're claiming to be an automaton because we're in a deterministic clockwork universe, but you could also be arguing that you're different from other people, either permanently or temporarily—perhaps there's something wrong with the way your mind works, or you're in a special circumstance which overrules your free will. In that case you may be functioning as an automaton while others are not.

          Even those solidly on the side of free will gene

          • by Immerman (2627577)

            Can you suggest any way short of some hypotheical mind-control in which a person could be deprived of free will? Without having some evidence that such a thing has truly happened you're simply granting someone a free pass on their actions. You could be damaged in such a way that certain options are no longer available, or I could hold a gun to your daughters head and say you must do X, Y and Z, but it is still your choice to value your daughter's life over the consequences of your actions. In the extreme

            • Can you suggest any way short of some hypotheical mind-control in which a person could be deprived of free will?

              I'm not sure there is any objective way to determine whether a person has free will in the first place, which would imply that there is no objective way to determine whether they've lost it. Manipulation of the information you receive would be one way to create a barrier between your apparent ability to make choices and their actual consequences, though you could still argue that you made the choices freely within the context of the information you had. Your ability to exercise your free will within the rea

  • I'm not surprised by this discovery. Evolutionarily, we're all really complex support systems for long meat tubes that ingest energy and building materials and excrete whatever is not useful. Even the mighty brain only exists to increase the odds of the tube surviving. Bacterial strains that also increase the chances of a meat tube surviving will be favored by simple Darwinian logic. Naturally, they will influence every body system, including the brain.

    Admittedly, one doesn't like to feel like a puppet. I w

    • > I wonder what this means for the free will that humans supposedly possess.

      Nothing, because free will isn't really a meaningful concept. It all falls apart when you try to define it. You either wind up with a meaningless definition, or no free will. It appears that we respond to stimulus in the only way we can based on our biology and past experiences. Free will became extremely unlikely when we realized that souls are imaginary.
      • by easyTree (1042254)

        Nothing, because free will isn't really a meaningful concept. It all falls apart when you try to define it.

        When definition proves difficult, often a series of examples allows the definition to be communicated indirectly.

        I'll start the ball rolling by responding only with the word 'cheese' as a full explanation of your incorrectness.

      • by Immerman (2627577)

        > Free will became extremely unlikely when we realized that souls are imaginary.
        Really, when did they prove this?
        Free will first became completely impossible when we discovered that everything in the universe operated according to deterministic physical laws.
        Then it became probably illusory when we discovered that quantum mechanics was non-deterministic and had an influence on brain function.

        I'm not overly inclined to believe in an personal immortal soul (which is an extremely narrow subset), but I can't

  • I was on antibiotics for a staph infection a while back, and I felt a general weakness and lack of drive. I know the antibiotics were working because I stopped farting, and my poops were relatively unprocessed and didn't stink.

  • by Ukab the Great (87152) on Friday February 21, 2014 @05:10PM (#46306849)

    When she told me that donuts would make me stupid.

  • Healthy bacterias (Score:4, Insightful)

    by gmuslera (3436) on Friday February 21, 2014 @05:13PM (#46306869) Homepage Journal
    Be careful with what makes you what you are. This shows the importance of not abusing generic/strong antibiotics, breast feeding childs for years (probiotics are probably an incomplete fix) and not removing your appendix [wikipedia.org] without need. If you don't care enough about that, may be a fecal transplant [mayoclinic.org] in your future.
    • It is often advisable (consult your doctor) to eat a probiotic food such as yogurt with live cultures when on, and after, an antibiotic treatment. I've become a fan of Kefir [lifeway.net].

      • by javelinco (652113)
        Probiotics have been shown to have a negligible impact on healthy gut bacteria. The only way, currently, to reliably restore gut bacteria colonies is to get a fecal transplant.
        • ... a negligible impact on healthy gut bacteria.

          If you are on an antibiotics regimen that is what you may not have. The idea is to replace them when the antibiotics have killed them. I've had doctors recommend it to me (eating yogurt when on antibiotics). I would now use Kefir.

          • by ceoyoyo (59147)

            The vast majority of doctors aren't scientists, and many believe all sorts of odd things. I'm not saying you're wrong. It is a reasonable hypothesis, but I'm not sure anyone has tested it appropriately.

            Some potential problems I see are that yoghurt and other "probiotic" cultures tend to be monocultures, or close to it, and have to pass through concentrated stomach acid. There are some good studies that show people exposed to a wider variety of microorganisms have healthier immune systems. Dirt would seem

            • The results of various antibiotics on gut bacteria are fairly well known - it kills them. The results on the digestive system can be "unpleasant." That is why you want to eat the yogurt, to aid in repopulating the gut with the bacteria needed for the digestive system to work properly.

              It's because of the monoculture problem that I've come to favor Kefir. Yogurts commonly only have 1 or 2 strains, I think I might have seen varieties that have 4, or maybe even 6. But Kefir, depending on the variety, will h

              • by javelinco (652113)
                Yes, that's what antibiotics can do - kill the bacteria. My concern is that you think yogurt gets them back. It doesn't work - that's what the scientific studies show.
                • Do they? The ones I remember seeing (IIRC) were trying to alter balance of existing gut flora, not replenish after a loss due to treatment with antibiotics. In that case, yes, that is what I recall - at least for a particular methodology for doing so.

              • by ceoyoyo (59147)

                I'm not disputing that antibiotics kill gut bacteria. But I don't know that there's any evidence that probiotic supermarket products help replenish it in any meaningful way. Remember that a normal course of antibiotics aren't going to kill everything anyway - the survivors will proliferate of their own accord once the antibiotic is discontinued.

                It's possible these products do help. If so, it still seems that dirt would be an even better alternative since the available evidence suggests that variety is ve

              • I think Kefir is going to be preferable to eating dirt since they all live nicely in the human gut. The stuff in dirt ...??

                The people who have Crohn's disease and going for the autoimmune treatment have been to Africa to stomp in some piles of shit to contract hookworm. Supposedly that works. I've heard it's possible to mail-order a porcine whipworm from Thailand which is more controlled and less likely to get out of control.

                It's all banned here in the US, so they just do lots of bowel resections. That

                • I think there has generally been a reluctance in Western medicine up until fairly recently to make use of therapies of that sort, probably for a lot of reasons. Drugs and surgery tend to be well known treatments, and have the halo of modern science and a certain specificity to them. Using leaches*, maggots, and hookworms would seem medieval, and to be something of a Pandora's box, even if it works. Still, at least some treatments of that sort are making a comeback.

                  Medicinal Leeches: Nature’s Finest [yalemedlaw.com]

                  • by Immerman (2627577)

                    Western medicine does seem to have an unhealthy fascination with the utterly-controlled and technological. For example we've known for 50+ years that dogs can reliably smell lung cancer long before it will show up in any tests, yet have you even once seen a cancer-sniffing dog used to perform fast, non-invasive screening anywhere in the country?

                    Perhaps it's a culture reaction to its rather incompetent and superstition-laden past. I just hope they get over themselves soon.

                  • Yes, if somebody were to build nanobots to selectively excise necrotic material that would be worthy of a Nobel prize, but maggots - barbaric!

    • Re:Healthy bacterias (Score:4, Informative)

      by HairyNevus (992803) <hairynevus@gmail . c om> on Friday February 21, 2014 @05:31PM (#46306997)

      "Another method of adjusting the bacterial profile of your gut is to undergo a transplant that involves taking faecal material from a donor’s intestine – often a close relative – and implanting into a recipient via enema infusion. This unorthodox treatment has been shown to successfully treat infections caused by pathogenic bacteria colonising the gut."

      Shit transplants....we've gone too far.

      • Hey, lots of species actually eat the stuff, especially scavengers whose gut is more prone to picking up invaders. Be glad our doctors have found a more palatable way to recolonize your colon.

        I wonder what the rational behind using a close relative is though? I mean I could see a spouse - they're unlikely to be carrying any serious infections you don't already share, but a sibling or parent? I suppose it's slightly less disgusting than getting a transfusion from some stranger, but come on, we're talking

  • I wonder when we can buy the first DIY gut-flora-transplant-kits from kickstarter.

    • by Immerman (2627577)

      A fecal-smoothie enema doesn't exactly require anything you can't pick up cheap at your local pharmacy, why would you go to Kickstarter?

      • A fecal-smoothie enema .... why would you go to Kickstarter?

        My guess would be to afford "marketing," .... maybe a snappy new name to put a fig leaf over it.

        • by Immerman (2627577)

          ... I was about to make a snarky comment about how pointless it is to spend money marketing something that can already be done trivially with cheap off-the-shelf components, and then I thought of about 90% of the garbage I've seen for sale.

          Well played.

  • I knew that since a few years.

    For example, multiple sclerosis seems to be related to some bacteria, that are inoffensive in the gut, but lethal in the brain (I'm pretty sure Parkinson's and Alzheimer's diseases are similar).
    The transfer from gut to brain is facilitated when your body loses his protections.
    For example, one of my friends triggered multiple sclerosis when his mother developed a cancer, he was very shocked.

    By the way, bifidobacterium is used to fatten pigs, so I would not recommend to fill your

    • by javelinco (652113)
      There is no way to identify when MS was "triggered" - so if your friend was told his mother developing cancer "triggered" his MS, I'd suggest he consult another doctor. MS is hard enough to diagnose as it is - MRI's, multiple symptoms, and often a spinal tap are used to diagnosis it, and most experts would say that there is no certainty even at that point.
    • by ceoyoyo (59147)

      There is some preliminary mechanistic evidence, and quite a bit of epidemiological evidence, that the gut microbiome is involved in autoimmune diseases, including MS. There is no evidence that gut bacteria migrating to the brain has anything to do with it, and considerable evidence that this is not the case. The specific causes of MS and other autoimmune diseases are unknown and probably very diverse. It's highly unlikely that a single event such as the stress of a loved one getting sick "trigger" them.

      P

      • Regarding MS specifically, there's a physician in Italy who is claiming ~85% remission of MS after brain veinous intervention. He has some theory about excess iron in the nervous system, but even if that's not right, if the vein blockage is causative there's still something causing that (which could be autoimmune mediated).

  • Considering that children with autism almost always have major digestive issues and will usually see dramatic behavioral improvement by moving to a strict gluten free, casein free diet that does not surprise me in the slightest. I will be very interested to hear what comes of this.

    • Considering that children with autism almost always have major digestive issues and will usually see dramatic behavioral improvement by moving to a strict gluten free, casein free diet

      You're exaggerating a bit. Digestive issues (and food allergies) are common in autistic people, but not "almost always". Often they're not severe problems either. As for the restricted diet, it does work for some, and it's certainly something worth trying for an autistic person, but it doesn't have any effect on most of them.

  • by Marrow (195242) on Friday February 21, 2014 @06:05PM (#46307337)

    When my gut is in an uproar, I don't have patience for mazes and puzzles either. Maybe they were just feeling sick. Add stress, and the feeling magnifies.

  • " It seems the flora in your intestines can influence brain development as well as aspects of health and nutrition" Would this mean that its possible to develop a diet that helps treat those with mental disabilities?
  • ...listening to your gut.
  • Google up GMO gut flora study for some fun and valuable prizes.
  • I think that fecal transplants are the main method of making gut bacterial changes, right?
  • If they determine that cognitive capability can be improved by bacteria, then it would make sense to add this to everyone's water supply.

    Based on the news I read, we desperately need it. Especially Toronto.

  • I can't eat stuff like yogurt or kefir or similar things because of lactose intolerance. If it's true that I need to have it all sorted out, what could I eat to replenish my gut bacteria without having to resort to painful milk derivatives?

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