Home » To be slim, you need to change your—gut microbiota?

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To be slim, you need to change your—gut microbiota? — 33 Comments

  1. The microbiome projects are also doing DNA sequencing of various populations to determine whether fatter groups in general have different microbes. They are also studying on the skin, in the mouth, and elsewhere. Given the number and variety of bacteria that coexist with us, there is so much to learn and so many possibilities for using simple bacterial treatments to improve our health. But we are at the beginning. I read somewhere recently that Heliobacter, the bacteria involved in ulcers, are actually beneficial in children. So all of this work is preliminary and will require a lot of sampling over longer periods and a huge amount of number crunching. A friend of ours is one of the leading people involved in this type of work, so I try to follow it.

  2. And of course, if famine comes, the slim people will be out of luck.

    I wouldn’t be too sure about that.

  3. Your weight loss columns haven’t fallen on deaf ears at the Davis household lol. Lively discussions!

    My wife and have both tried weight loss regimens that have worked (for her, measurement: counting every damn calorie taken in, and balancing against estimated calories used …for me: low carbs and “appetite control”).

    But jeezus: it is a hard slog.

    Your views – to paraphrase “often there’s not much you can do” – and the revelation of your caloric intake when you were a young dancer (1,000 cal’s a day max as I recall …and even that being just barely adequate for weight control) – gave us both pause. Dancing? On a 1000 cal’s a day? Jeezus.

    Coupled to that, we also came across the gut microbial thing a few months back …and came to the understanding that everything we’ve ever read …may just be flat out wrong. It was just …speculation …and now to be consigned to other past follies; the purveyors on a level with snake-oil salesman with good intentions. The alchemists of the 20th century.

    …in the end, they were just witch doctors.

    IOW, the previous “science” may be more akin to superstition & fables, than science.

    A pill.

    In the end, it may be as simple as a pill that actually DOES cure obesity.

    Like my ulcers of years back, which were cured when someone finally figured out it wasn’t stress (but was the bacteria H pylori), over-eating & obesity seems to be the result of a common bacteria …and the cure will be participation in a short antibiotic regimen.

    But …dietary science?

    Sometimes, “science” is not what you think it is (or should be) at all.

  4. Imagine all the money going to studying snail sex, the horniness of horny corals, effects of Penis Size in the Gay Community (NIH-backed), Bill Gates’ grant for ‘next generation’ condoms, etc. going to studying “gut microbiota”. Talk about misplaced priorities – sex still sells.

  5. Gates’ compulsion comes from the need to diassociate himself from Micro Soft.

  6. I think Alferd’s evil twin Alfred would feel the same way.

    A common misconception. “Alferd” is the correct spelling, of what was presumably Alferd’s parents’ mistake.

  7. What if:

    it were possible to change our intestinal bacteria in some safe way, perhaps a few cups of a special yogurt, so that we could all eat to satisfy our appetite without gaining weight beyond a healthy amount.

    Would this be a good thing? Is it a desirable goal for research?

    Or, in a world of limited resources, would it increase the cost of food for those around the world most in need of enough food and least able to pay for it?

  8. Jim Nicholas: I don’t see that it would, because (at least as far as I know) the amount of food consumed in this country doesn’t seem to affect the price of food in other countries. I also think that, for the most part, people would probably eat about the same amount, they just wouldn’t be as overweight.

    Could be wrong about that, of course. There might be a rash of gluttony at the beginning, but I think people would get tired of it.

  9. Something does not add up in the microbiota thesis (and I am not disputing the facts of the matter): The obese bugs ‘wrest’ every calorie from the food ingested, but the slim bugs do not, it is interpreted.

    Well then, to what uses are the fat bugs putting their calories? They cannot be a bottomless energy sink. Their hosts stay fat. And the slim bugs, who leave ingested calories for the host’s use, cause slimming by leaving more food for the human host?

    Should be the other way around, based just on the calorie thesis (calory is an energy unit). But I never overestimate the ability of jornolists to misunderstand.

  10. Don Carlos: I interpreted it differently—although I agree with you that the quality of much science journalism is abominable (sometimes fool, sometimes knave).

    The way I interpreted the part you’re referring to is that, in addition to our basic digestive juices, bacteria help break down the food so that we can assimilate it. The fat bugs help the host break down and assimilate calories to the host’s use. The slim bugs somehow interfere with that process, at least to a certain extent (not too much, because the host would then starve to death). The slim bugs are not actually slim themselves—they help keep the host slim by not facilitating digestion as well as the fat bugs. As for whether the slim bugs themselves take in the extra nutrients that are not assimilated by the host—I don’t know. Perhaps they do to a certain extent; I’d not sure what the bugs get out of the deal (fat or slim), but it’s probably something or they wouldn’t be there. Maybe it’s just a nice warm home.

    I suppose I could look it up and find out more—so here goes:

    The human body carries about 100 trillion microorganisms in its intestines, a number ten times greater than the total number of human cells in the body. The metabolic activities performed by these bacteria resemble those of an organ, leading some to liken gut bacteria to a “forgotten” organ. It is estimated that these gut flora have around a hundred times as many genes in aggregate as there are in the human genome.

    Bacteria make up most of the flora in the colon and up to 60% of the dry mass of feces. Somewhere between 300 and 1000 different species live in the gut, with most estimates at about 500. However, it is probable that 99% of the bacteria come from about 30 or 40 species. Fungi and protozoa also make up a part of the gut flora, but little is known about their activities.

    Research suggests that the relationship between gut flora and humans is not merely commensal (a non-harmful coexistence), but rather a mutualistic relationship. Though people can survive without gut flora, the microorganisms perform a host of useful functions, such as fermenting unused energy substrates, training the immune system, preventing growth of harmful, pathogenic bacteria, regulating the development of the gut, producing vitamins for the host[citation needed] (such as biotin and vitamin K), and producing hormones to direct the host to store fats…

    Using several diets with different concentrations of four ingredients, casein, corn oil, cornstarch, and sucrose, it is possible to feed a linear model to predict the abundance of each species as a function of diet. This model is able to predict 61% of population variation…

    Without gut flora, the human body would be unable to utilize some of the undigested carbohydrates it consumes, because some types of gut flora have enzymes that human cells lack for breaking down certain polysaccharides. Rodents raised in a sterile environment and lacking in gut flora need to eat 30% more calories just to remain the same weight as their normal counterparts. Carbohydrates that humans cannot digest without bacterial help include certain starches, fiber, oligosaccharides and sugars that the body failed to digest and absorb like lactose in the case of lactose intolerance and sugar alcohols, mucus produced by the gut, and proteins. A further result is flatulence, specifically due to the metabolism of oligosaccharides (notably from beans) by many different species.

    Bacteria turn carbohydrates they ferment into short chain fatty acids (SCFAs) by a form of fermentation called saccharolytic fermentation. Products include acetic acid, propionic acid and butyric acid. These materials can be used by host cells, providing a major source of useful energy and nutrients for humans, as well as helping the body to absorb essential dietary minerals such as calcium, magnesium and iron. Gases and organic acids, such as lactic acid, are also produced by saccharolytic fermentation. Acetic acid is used by muscle, propionic acid helps the liver produce ATP, and butyric acid provides energy to gut cells and may prevent cancer. Evidence also indicates that bacteria enhance the absorption and storage of lipids and produce and then facilitate the body to absorb needed vitamins like vitamin K.

    It goes on and on and on, quite a long and informative article. I’ve known ever since I read Life on Man when it first came out in the late 60s that the gut harbored tons of flora and fauna, and that some were beneficial. But I had no idea they now knew that much and were studying it that deeply.

  11. Neo-
    The lead-in article was about calories. A calorie, as I earlier indicated, is a unit of energy. One cal. of energy raises the temperature of one gram of water by one degree Celcius (that’s the definition). Counting energy tells us nada about the uses of energy. It tells us nothing, nor does the tagged article, about the uses, good or bad, on which that energy is expended.

  12. Neo,
    Just to add to the complication, these bacteria will adjust their metabolism to substances they find in their environment. And some of what they find may well be excretion products of other bacteria, which in turn respond to the environment in terms of uptake and excretion. I suspect that identifying a single bacteria that does something is the rather easy first step. Figuring out all the interactions is really tough.

  13. Neo: “(at least as far as I know) the amount of food consumed in this country doesn’t seem to affect the price of food in other countries.”

    You may be right, but I have some doubts.
    1–I was assuming that the preventative for obesity would be available world-wide to those who had the luxury to satisfy their appetite.
    2–There is a world market and a world price for grains much as there is for oil.
    3–Foods that are less likely to have a world market and a world price, such as meats, deplete the world grain stores faster than diets of grain.
    4–China is a clear example of the effect on the world price of grains of a changing diet in a single country . The emergence of millions of Chinese out of abject poverty, enabling them to eat more meat as well as more grain, has led to a significant increase in the world price of grains, of which China is now a net importer.

    And so I still wonder if it is desirable to have a product that enables persons in United States and throughout the world to consume more food.

    Incidentally, I have the same concerns about work going on to find a way to stimulate the metabolism of brown fat, a kind of fat in persons (more active in some persons that in others) that burns off unneeded calories that have been absorbed.

  14. Jim Nicholas: well, if you’re talking about this product being available around the world, I suppose it would affect the food supply worldwide. However I’m not at all convinced that even were it to be available worldwide that people would actually be eating that much more as a result.

    Here’s my reasoning on that: we’re talking about two different things here, weight vs. appetite. The theory is that people eat a certain amount which is determined by appetite, and some end up thinner and some eat up fatter even eating similar amounts, because of these different bacteria (which are of course not the only factor, but they’re the factor we’re talking about in this thread). What the change of bacteria is supposed to do is to make it possible for heavier people to eat the same amount as always and yet be thinner than before. This does not mean that their appetite would increase and they would eat more food than before, unless you think somehow that being thinner will increase their appetite in some automatic way. I don’t think it will for most people, because I think appetite is appetite and satiety is satiety and not usually dependent on weight.

    The exceptions might be people who have restrained their intake tremendously in order to be thin, and who now will be freed up to eat more. That represents most successful dieters who have lost weight and kept it off, which supposedly represents about 1% of dieters, not a huge number of people.

    It may turn out that if people get this treatment and it’s effective, they will go hog wild and eat and eat and eat, but I just don’t think so—and it would also be very expensive to do that.

  15. Something does not add up in the microbiota thesis (and I am not disputing the facts of the matter): The obese bugs ‘wrest’ every calorie from the food ingested, but the slim bugs do not, it is interpreted.

    Well then, to what uses are the fat bugs putting their calories? They cannot be a bottomless energy sink. Their hosts stay fat. And the slim bugs, who leave ingested calories for the host’s use, cause slimming by leaving more food for the human host?

    Should be the other way around, based just on the calorie thesis (calory is an energy unit).

    Ah, the voice of sweet reason. I was wondering if anyone else would see this problem.

    It tells us nothing, nor does the tagged article, about the uses, good or bad, on which that energy is expended.

    Two for two, Don Carlos.

  16. And the slim bugs, who leave ingested calories for the host’s use, cause slimming by leaving more food for the human host?

    Damned decent of them, not to use these calories going begging to reproduce under such ideal conditions (37 C – woot!) up to the point where nutrients become population limiting. Bacteria everywhere could learn something about social responsibility from them. Bacterial ZPG. Maybe they drive Priuses too.

    As it happens, one of my research areas involved bacterial iron transport in E. coli, and those bastards reproduced logarithmically until they ran out of nutrients. They didn’t share a goddamned thing with anybody. Probably Republicans, now that I think of it.

    Bottom line: the conclusions of this paper are probably of a piece with most of the biomedical literature, i.e., largely composed of dead bacteria that are typically dropped into a porcelain receptacle. But if it makes you feel better to lay off responsibility for obesity to prokaryotes, go for it.

  17. Occam’s Beard: to be blunt, what makes you think I give a rat’s ass what’s responsible for obesity, except in terms of trying to find out the truth? I don’t have a dog in this race.

    As you did in the comments section of this older thread about obesity, you continue to be intensely invested in the need to blame heavy people for their plight and to debunk anything that might suggest otherwise.

    I’m reporting on some research and its results. I’m neither a physiologist nor a doctor nor a biologist. My point is that it’s apparent that there are hundreds and hundreds of types of bug that can dwell in the human gut, but people have different mixes. The bugs are specialists—some help break down a certain type of nutrient and some another, and in the breakdown process can leave a substance that’s more digestible to humans. Different mixes of bugs work differently from each other; some work on one type of nutrients and some on others.

    Did you even read the excerpt from the Wiki entry that I offered in my previous comment? Do you think, for instance, that the following is a lie or an error of some sort on the part of the scientists who study the human gut and its flora/fauna in depth?:

    Bacteria turn carbohydrates they ferment into short chain fatty acids (SCFAs) by a form of fermentation called saccharolytic fermentation. Products include acetic acid, propionic acid and butyric acid. These materials can be used by host cells, providing a major source of useful energy and nutrients for humans, as well as helping the body to absorb essential dietary minerals such as calcium, magnesium and iron.

    Here’s more about studies of the different sort of bugs that are commonly found in slim vs. fatter people:

    A second study by a different group found that overweight people may be more likely to harbor a certain type of intestinal microbe. The microbes may contribute to weight gain by helping other organisms to digest certain nutrients, making more calories available. That study was published Tuesday in the Journal of Clinical Endocrinology & Metabolism.

    The study involved 792 people who had their breath analyzed to help diagnose digestive orders. They agreed to let researchers measure the levels of hydrogen and methane; elevated levels indicate the presence of a microbe called Methanobrevibacter smithii. The people with the highest readings on the breath test were more likely to be heavier and have more body fat, and the researchers suspect that the microbes may be at least partly responsible for their obesity.

    This type of organism may have been useful thousands of years ago, when people ate more roughage and needed all the help they could get to squeeze every last calorie out of their food. But modern diets are much richer, said an author of the study, Dr. Ruchi Mathur, director of the diabetes outpatient clinic at Cedars-Sinai Medical Center in Los Angeles.

    “Our external environment is changing faster than our internal one,” Dr. Mathur said. Studies are under way, she said, to find out whether getting rid of this particular microbe will help people lose weight.

    I find it interesting. I have no idea whether that would work, and I submit that you don’t, either.

    How about this: if it makes you feel better to think heavy people are weaklings with no will power, and to think these scientists are abysmally stupid and/or are lying, go for it.

  18. Neo to Occam:

    How about this: if it makes you feel better to think heavy people are weaklings with no will power, and to think these scientists are abysmally stupid and/or are lying, go for it.

    I’ve bitten my tongue in the previous threads, despite concerted efforts that yielded significant weight loss and muscle gain in the past 2 years.

    I think you really are arguing at cross-purposes – and inadvertently bolstering Occam’s suspicion (which I kinda share) that people cling to various scientific red-herrings to avoid some basic responsibility and self-control issues.

    Even with this new theory – there is obvious relationship between the diet ingested and the profile of bacterial flora. It’s suggested that the benefits of gastric bypass – a radical surgery – could be realized without the intrusion or risk.

    How?
    Obviously, by behavior modification – eating “like a thin person” until your flora molds itself to the new pattern.

    No biologists would agree with the notion that seeding your gut with thin bacteria would somehow compensate for patterns of overeating… given the interaction between substrates consumed and the resulting bacterial eco-system, it’s much more likely the influence works the other way around – and overweight people likely already have “thin” bacteria in their guts, but in a different mix.

    Determined by (genetics and) what they *choose* to ingest, and how much they *choose* to exercise.

    Which brings us back to Ocaam’s focus on behavioral choices as the starting point – confirmed by my own experience: no weight loss happens without denying habituated appetites (and even social norms) and changing one’s behavior.

    The underlying vectors are “nice to know” – but misused to deflect the focus from what the individual can do.

  19. Ben David,

    Obviously intake affects weight, but this research should at least point out that no single diet will be ideal for everyone. It should point us to humility, common sense and experience rather than the one size fits all food pyramids we have been taught to trust.

  20. Possible mechanisms of action that are compatible with calorie in, calorie out, calorie stored balance:
    1–Some bugs pre-digest some foods and make the calories in them available for absorption, thus promoting weight gain.
    2–Some bugs convert foods that are usually absorbed into substances that cannot be absorbed and so are passed on in the feces, thus promoting weight loss.
    3–Some bugs capture more food for themselves and keep it in themselves, resulting in a larger mass of bugs in the feces and thus promoting weight loss.
    4–Some bugs block the absorption mechanisms of the intestinal cells, resulting in food that is usually absorbed being passed on in the feces and thus promoting weight loss.
    5–Some bugs enhance the absorption mechanisms of the intestinal cells, this promoting weight gain.

    I do not know how these “fat” and “thin” bugs do act, if they do, but those five possibilities all seem possible. Certainly #4 is a factor in many diseases.

  21. On Neo’s comment to Occam: “you continue to be intensely invested in the need to blame heavy people for their plight and to debunk anything that might suggest otherwise.”

    Not at all what Occam was saying. Occam and I are merely responding to the calorie (energy) thesis reported by a journalist. The essence of the scientific method is the production of reproducible results. Non-scientists will take one-time results and run with ’em, extrapolating those results to all sorts of effects, instead of challenging and/or verifying the data as the first step.

  22. Don Carlos: I was not referring to the factual content of Occam’s Beard’s comment, I was referring to his characterization of MY motivations, plus the lengthy back-and-forth exchange we had in another recent thread (which I linked to) about the causes of overweight, in which he had an angry tone that was quite attention-catching (he even apologized there briefly for his snarky tone, but intermittently resumed it).

    In this thread, I was specifically referring to the statement he made that I paraphrased, “But if it makes you [neo-neocon] feel better to lay off responsibility for obesity to prokaryotes, go for it.”

    I’m neither “laying off responsibility” nor “feeling better” about it. At no point here did I give my opinion about whether or not this research will end up being correct, I merely report it because it’s an interesting development I’d never heard about before. As for how I feel about it, I’m agnostic on the subject. As I’ve said several times before, I am not fat, although for fashion’s sake I’d like to lose the usual 10-15 points. What’s more, although I have restrained my eating and exercised my entire life, I would probably need to continue to do so even if I ingested these bacteria, because of other health reasons (cardiovascular health, for example, and just liking to exercise because I feel better when I do it).

    The implication Occam’s Beard is making is that my emotional desire to “lay off responsibility for obesity to prokaryotes” (because it makes me feel better) is the reason I’m somehow pushing this, and/or not accepting his obviously convincing arguments. I don’t find his arguments convincing not because of any emotional need I have but because they’re just not convincing to me, but I have no idea whether this research is correct or not, and as I said have no dog in this race. Even if these bacteria were a proven overweight remedy I doubt that my weight would even qualify me for the treatment, much less whether I’d take them (I’ve already voiced some doubts of my own in the post about the long-term health consequences of taking them).

  23. Jim Nicholas:

    Yes, your list is the sort of thing I was trying to get at.

    You said it much better than I.

  24. Neo:
    I tend to take each of your essays and the comments made thereto as stand-alones, and respond in that vein.
    It saddens me that a ‘scientific’ issue (if the journalist is to be believed) should be pulled down by non-scientific thinking and words.

  25. I do not know, of course, is it true or false, but from general biological assumptions this seems VERY plausible. No mammalian species can even survive without symbiosis with gut bacteria, even less be healthy without it. In food processing these bacteria play crucial role, and there were tons of recent publications highlighting this role. So this article is not a freak event, just another fact finding in a huge mountain of constantly growing recent evidence of importance of this symbiosis.

  26. What is called energy content of the food is a chemical abstraction based on complete ‘burning’ of organic stuff. But physiology never works this way. Lots of organic stuff stay unprocessed in feces, more than half of it, and this proportion depends on composition of gut bacteria community. It must be stressed that this community is a stable system, a whole ecosystem which adjust itself to uptake food composition but is resilient, steadfast and hard to change.

  27. What Occam failed to understand is that in any real biological environment bacteria never behave as they do in pure culture in test tubes, that is, they do not replicate exponentially until all available substrate is consumed. There are dozen and hundred bacterial species in a complex network of metabolic pathways, where some species provide food for another species, and where are many cooperative, antagonistic and competitive interactions. Such system self-organizes to some stable state in which relative abundances of each type are strictly regulated. Different segments of digestive tract have different microbes in them, and even in the same segment different types occupy different layers of microbial films covering intestines.

  28. Good description, Sergey. Identifying a few species associated with obesity is only a tiny step in understanding the whole system.

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