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I have gut feeeling this is sweet.
August 21, 2007 3:50 AM   Subscribe

I really enjoy discoveries that, in retrospect, should have been obvious (but weren't). It's not just your tongue that can taste sugar.
posted by orthogonality (53 comments total) 1 user marked this as a favorite

 
It's been mentioned that aspartame can cause havoc with diabetics' ability to control their blood sugar levels -- wouldn't shock me if this was related. The body might be reacting like it's getting sugar, when it actually isn't.
posted by Malor at 4:04 AM on August 21, 2007


That title is stretching my patience with you.
posted by poppo at 4:31 AM on August 21, 2007


Do you have a reference for that Malor? I couldn't find anything. I've followed the Aspartame literature ever since I switched to diet cola and had to repeatedly defend myself from the "Aspartame is bad for you" crowd.
posted by srboisvert at 4:32 AM on August 21, 2007


Pedantry alert, the gut doesn't actually taste the sugar, it senses it. There's a difference. (Hell my eyes and fingers can sense sugar, too.)

Oddly when I first read the front page post I was convinced that this would be a story about fingers, weird.
posted by oddman at 4:40 AM on August 21, 2007


This might explain why obesity increased after the introduction of artificial sweeteners, or maybe not.
posted by BrotherCaine at 4:53 AM on August 21, 2007


I'll see what I can dig up... it made me extremely ill, to the point that they thought I might have MS. I've been exposed to a great deal of information about it... I'm absolutely certain the source was a doctor, but I don't remember where I read it.

Aspartame, at least for some people (including me) is pure evil. It messed me up bad.
posted by Malor at 4:53 AM on August 21, 2007


I immediately imagined putting sugar into my pants. And then I thought, it's true- that really should have been obvious.

On a side note, a friend of mine pronounces "aspartame" as if it rhymed with the phrase "as part of me." She has done this enough times that it's the first pronunciation that leaps into my head whenever I use the word.
posted by jiiota at 4:54 AM on August 21, 2007


Sweet post, orthogonality!

Hell my eyes and fingers can sense sugar, too.

The difference is that your eyes and fingers don't sense sugar using exactly the same mechanism as your tongue.
posted by grouse at 4:56 AM on August 21, 2007 [2 favorites]


That's the only pronounciation of "aspartame" that I know! Is that this side of the pond?
posted by Wilder at 4:59 AM on August 21, 2007


Wilder- I guess some other people pronounce it ASS-per-tame. I don't know which is correct, but I do know that I always choose the pronunciation that earns me the most ridicule amongst the people I'm speaking to.
posted by jiiota at 5:05 AM on August 21, 2007


I just don't have the stomach for this.

sorry
posted by chillmost at 5:06 AM on August 21, 2007


Interesting, Wilder. The OED says uh-SPAR-tame and the Cambridge Advanced Learner's Dictionary says AS-per-tame. Merriam-Webster gives both. I've only ever heard AS-per-tame. Never as-part-uh-me.
posted by grouse at 5:11 AM on August 21, 2007


I'm assuming my stomach isn't using photons to sense sugar. If it's being sensed chemically (by non-airborne chemicals) then the difference between this and taste is negligible.
posted by DU at 5:16 AM on August 21, 2007


oddman writes "Pedantry alert, the gut doesn't actually taste the sugar, it senses it. There's a difference. (Hell my eyes and fingers can sense sugar, too.)


As grouse points out what makes this a "should have been obvious" is that the mechanism in the gut is the same as the mechanism in the tongue. So it makes sense that, having a working mechanism in the genes, parsimonious evolution would express it both in the gut, where concentrations of glucose lead to metabolic responses, and in the tongue, where concentrations of glucose lead to behavioral responses ("yum! tasty! let's have more!).

Of course we can argue that the tongue's mechanism is reported to consciousness ("yum! tasty!") and that the gut's isn't, but I'd argue both can be called "tasting". And if we see that reporting to cosciousness as the crux of the distinction, then don't have to call non-human sugar tasters conscious? Dogs, ok sure. Hummingbirds? Um, maybe. Flies? Conscious flies? Um, not so much. But they taste sugar (in bristles all over their bodies rather than in tongues, admittedly).


Of course, I'm grinding an axe here, just a bit. (I also find the linked article fascinating in itself.) I want to keep harping on the similarity of "metabolic" unconscious, "mechanical" biologic processes on the one hand, and "conscious", willed, biologic "behaviors" and "preferences". (I should have also linked to studies showing that neurotransmitters, in particular serotonin, used for signaling in the in the gut as well as in the brain.)

My larger purpose is, as ever, to convince you that if flies are "biological robots", with sensors that when stimulated initiate both metabolic processes and "behaviors", then we humans are also, to a greater extent than we often realize, "biologic robots"; and that life and consciousness are not mysteries or necessarily carbon-based, but algorithms and data structures that are in principle discoverable by reductionism and reproducible in non carbon-based media.
posted by orthogonality at 5:22 AM on August 21, 2007 [6 favorites]


Seems pretty likely to me... but it's worth pointing out that it's possible that part of consciousness is carried at quantum-level interactions.

What we've been finding so far with evolutionary algorithms is that things come out working in very, very strange ways. Evolution grabs anything that works that's in reach, so it would surprise me very much if human consciousness *didn't* function at some level of quantum weirdness. We've already seen similar behavior in the laboratory...evolved chips with apparently-disconnected components, that nonetheless require the components to be present to function. The chips work, but we don't understand why. And that's just with simple FPGAs in the lab... get a few billion brain cells and all kinds of weird shit is gonna happen.

Reproducing things like consciousness in computers may be even harder than we already think it is. If it's sufficiently quantum, it may not be something we're smart enough to do, period. One could also argue that we can probably only create intelligences that are less complex than we ourselves are.

But boy, did this ever go far afield from the tasty intestine. :)
posted by Malor at 5:38 AM on August 21, 2007


Oh, but, orthogonality and malor, the discussion of the essence of "life-being-consciousness" is quite interesting. Maybe you can team up and make a post about it. hmmm, tag-team post?
posted by mightshould at 5:54 AM on August 21, 2007


Malor writes "it's possible that part of consciousness is carried at quantum-level interactions. "

Meh. Penrose is a great physicist and I love his tiles, but that's hand-wavy straw-grasping. And as you point out even if consciousness relies on quantum-level interaction, that's (contra Penrose) no reason to believe those couldn't also be discovered reductively and reproduced in AI. Even if we can't understand it, we could in principle reproduce it (surely genes don't "understand" it, but they can, given a suitable medium, reproduce it).

To my thinking, "tasty" intestines are just another example of the commonality of mechanism, across all species and all functions of the organism: the human brain and its effects (consciousness, etc.) are not in principle different than the human tongue or gut, or the fly's gut, or algorithms in silicon; it's all just matter and information.
posted by orthogonality at 5:56 AM on August 21, 2007 [3 favorites]


Of course we can argue that the tongue's mechanism is reported to consciousness ("yum! tasty!") and that the gut's isn't, but I'd argue both can be called "tasting".

Yes, your gut detects something sweet with the same sort of receptors your tongue uses to detect something sweet, but that's as far as you could argue it. Your gut tastes nothing like your tongue tastes a piece of chocolate, which, if you're like some people I know, makes you actually go limp in the spine and moan with pleasure.

By the way, I thank everyone for not misspelling 'tongue' here. Certain misspellings (including 'tounge') always leave a bad taste in my mouth.
posted by pracowity at 5:57 AM on August 21, 2007


This post has left a horrible taste in my gut.
posted by itchylick at 5:59 AM on August 21, 2007


We've already seen similar behavior in the laboratory...evolved chips with apparently-disconnected components, that nonetheless require the components to be present to function. The chips work, but we don't understand why.

Link, please?
posted by designbot at 6:04 AM on August 21, 2007


On a side note, a friend of mine pronounces "aspartame" as if it rhymed with the phrase "as part of me." She has done this enough times that it's the first pronunciation that leaps into my head whenever I use the word....Wilder- I guess some other people pronounce it ASS-per-tame. I don't know which is correct, but I do know that I always choose the pronunciation that earns me the most ridicule amongst the people I'm speaking to.

I think both pronunciations are fine, I think. I know I've heard 'ass-per-tame' on TV, though.
posted by delmoi at 6:10 AM on August 21, 2007


Your gut tastes nothing like your tongue tastes a piece of chocolate

No one ever said the gut can taste chocolate like your tongue does, but it tastes sugar like your tongue does. Besides, much of the flavor of chocolate is sensed in the nose, which has a much more versatile set of receptors, not the tongue.
posted by grouse at 6:10 AM on August 21, 2007


So, let's see.

I'm not sure that I agree that it "should have been obvious" to us that the gut and tongue share certain structures. On one level, sure they both need to detect food, but beyond that they have very different purposes. In any case as to whether it's a head slapper, is probably more a function of one's own background. I'll grant that people who know more about biology might find it more "shockingly" obvious than I.

Well, I would indeed argue that reporting to consciousness, i.e. having a qualitative perception, is an essential part of tasting. This does imply that animals are sentient, but not that they are conscious. Sentience is all that is required for sensory impressions. (This is assuming that animals do indeed taste things in the same way that we do, but that seems like a likely event.) Of course, any sensing that doesn't involve a qualitative perception is not tasting.

As for the reducibility claim, I certainly do not follow you on that score. I do think that humans are, to some extent, "biological robots." We are, after all, inextricably linked with our bodies. However, I think there are quite a bit of things that defy reduction, for example: morals, qualia, will, and intentional thought.

(I will admit, however, that the recent trend to think about features of the world as a data structures instead of as a physical properties is something that I can't seem to get my head around. I assume that data structure s not just contemporary jargon that is just the equivalent of an older term like property but I can't seem to conceptualize the new way of thinking.)
posted by oddman at 6:13 AM on August 21, 2007


OK, replace 'chocolate' with 'sugar' -- there's still no 'mmmm!' involved with the gut's response. What is missing is what we normally refer to as 'tasting' something.
posted by pracowity at 6:15 AM on August 21, 2007


I think both pronunciations are fine

As we all know, I'm Mister Descriptivist, and anything native speakers say is fine with me, but those of you who say "as-PAR-tuh-mee" (if I'm understanding jiiota correctly) should be aware that prescriptivists would consider it merely wrong. As grouse points out, dictionaries differ on stress (I say ASS-per-tame myself), but always give it as three syllables. It's from aspartic 'of or pertaining to asparagine' plus the suffix -ame, if that helps.

Interesting post!
posted by languagehat at 6:20 AM on August 21, 2007


There's no accounting for taste.
posted by fuse theorem at 6:30 AM on August 21, 2007


pracowity writes "OK, replace 'chocolate' with 'sugar' -- there's still no 'mmmm!' involved with the gut's response. What is missing is what we normally refer to as 'tasting' something."

Quite possibly. On the other hand, perhaps the "mmm" is the feeling of satiety or of contentment after a sugary meal?
posted by orthogonality at 6:33 AM on August 21, 2007


orthogonality- For me, at least, especially as regards chocolate, or coffee, or even better tiramisu, the "mmm" response is immediate. The feeling that follows is usually more "ugh. I shouldn't have eaten so much of that."
posted by jiiota at 6:37 AM on August 21, 2007


Interestingly the "ugh, I shouldn't have eaten so much of that" feeling does come from the gut. Hmmmmm......... :)
posted by oddman at 6:44 AM on August 21, 2007


I have always assumed that these cravings came from a time in evolution when all animals- including humans- had such a short life expectancy that long-term health issues didn't matter as much as the benefit of short-term energy gains- being able to outrun a predator, or to chase down some food. Also, the opportunity to overindulge wasn't present back then. It seems like we have outrun evolution a little bit.
posted by jiiota at 6:45 AM on August 21, 2007


Taste, for me, indicates a conscious awareness. Although your gut uses, evidently, the same mechanical process as your tongue, your gut is not wired into your consciousness.

I don't know if the mechanisms are similar but that would be like saying that when you get a suntan it is because your skin could "see" the sun. It reacted to it, it didn't SEE it.
posted by dirtdirt at 6:49 AM on August 21, 2007


designbot: I'm 99% sure that was an article in the San Jose Mercury News.... geeze, it could have been as long as ten years ago. It's been QUITE awhile since I last read it. I can't find it anymore; it may no longer be in their online archive.

A very quick summation from memory: human designer writes an algorithm to design FPGA circuits. The circuit is supposed to turn on when a human says 'go', and stop when a human says 'stop'. Algorithm tries totally random setups until it gets voltage on the output pins, and then refines from there.

A human designer would make that circuit, if I recall correctly, in about 100 components, using timing loops to determine what the human had said. The evolutionary algorithm used far fewer. The first number that comes to mind is 11, but it's just been too many years to be sure anymore. Certainly less than 25. Circuit works fine, but is unbelievably complex, using bizarre connections all over the darn place. The programmer stared and stared and stared at it and still had no freaking idea how it worked: it was, according to him, entirely beyond his understanding, and he believed that no human could design such a thing. Further, as he probed the circuit, he found three or four components that had been programmed into the FPGA but weren't connected to anything.. They looked useless, but if he turned them off, the chip stopped working.

The thing I took away from that is that if we get evolutionary algorithms going, it'll change the nature of technology profoundly. At the moment, we broadly use technologies we don't understand, but someone, somewhere, does. If it breaks, eventually, we can get an expert opinion to determine why. Most of us have no clue, but there is always someone who does.

With evolutionary chips, we'll move to technology that nobody on the planet understands... it works, but we don't understand why it works.

BUt I gather the're having trouble, since I read that article so long ago and I haven't seen much come of it. I remember reading one followup where they discovered that the chip design wasn't very reliable across different FPGAs, and needed a very specific temperature range to work, so that particuar circuit tuned out to be very fragile indeed.

Anyway, what I was originally aiming at: if a simple evolutionary algorithm on an FPGA can hit on Weird Shit to work, chances are pretty good that real evolution did the exact same thing. And if it did, that makes the consciousness problem many orders of magnitude harder, because instead of just tracing neurons, any cell can potentially interact with any other cell via spooky remote action. It'll most likely be ones fairly close by, but if any cell can interact with any of a couple million others without a visible connection, that's gonna play hell on the researchers.
posted by Malor at 6:58 AM on August 21, 2007 [1 favorite]


Damn. I clicked on the link hoping it would say my penis could taste sugar.
posted by dances_with_sneetches at 7:13 AM on August 21, 2007


So, If I'm reading this right, when I'm eating a hot dog, it might, to a small extent, also be enjoying the taste of me?
posted by Astro Zombie at 7:24 AM on August 21, 2007


Usually these receptors stop working at death, but maybe if it were a zombie hot dog.
posted by grouse at 7:30 AM on August 21, 2007 [3 favorites]


Mr. Smith gets in a bad car wreck and wakes up in the emergency room in a full body cast, with just airholes for his nose, mouth and pooper. He starts screaming "COFFEE!!! Gotta have COFFEE!!!"

The nurse comes in and says, "Sorry Mr. Smith, the doctor says no hot liquids for at least 24 hours. Your system needs time to overcome the shock."

"NOOOOOO!!! GOTTA HAVE COFFEE RIGHT NOW!!!" wails Mr. Smith.

The nurse says, "Well, the best I can do is give you a coffee enema. That's about all I can do for you right now."

Mr. Smith cries "SURE....ANYTHING ANYTHING!!! GOTTA HAVE MY COFFEE NOW!!!"

So the nurse goes back to the nursing station, brews up a hot fresh pot, fills up the bag, goes into the room and plugs Mr. Smith up.

"AAAAAAAAAAAAGH!!!!" moans Mr. Smith.

The nurse says "What's the matter, is it too hot?"

Mr. Smith yells out "TOO MUCH SUGAR!!!"
posted by mr_crash_davis at 7:36 AM on August 21, 2007 [9 favorites]


Why can't I find either of the cited papers, or anything by the interviewed researcher, in the August 20 PNAS Early Edition? Stupid press release.
posted by rxrfrx at 7:53 AM on August 21, 2007


If the gut uses the exact same sensing mechanism as the tongue it is going to be mighty difficult to make an artificial sweetener that tastes sweet to the tongue yet fails to trigger a response in the gut. I wonder how Miracle Fruit works on these cells. If it binds to the tongue won't it also bind to the cells in the gut? Perhaps something that breaks down in the stomach might work, it provides a sweet taste to the tongue and then is broken down into a nonsweet substance prior to entering the small intestine.
posted by publius at 8:33 AM on August 21, 2007


there's still no 'mmmm!' involved with the gut's response.

Says you. As someone who's become lactose intolerant over the years, whenever I drink a chocolate milk, my guts get VERY vocal.
posted by davelog at 8:35 AM on August 21, 2007


This article demonstrates the difference between sensation and perception. Sensation refers to how the outside world is detected (e.g. that there's sugar present), whereas perception refers to how it's perceived (e.g. "That's sweet!"). A classic example is the face/vase illusion. The sensation is exactly the same, but in some cases, it's perceived as two faces, and in others, it's perceived as a vase.

Malor: When I was in grad school, I briefly entertained the idea of doing research in "non-local" neural communication, but from a classical physics perspective. Whenever a neuron fires, it produces an action-potential - a flip in the polarity of the electric field travels down the length of the axon until it reaches the terminal button where neurotransmitters are released to talk to the next cells. It's the millions of action potentials which produce slight changes in voltage on the scalp that EEG machines measure.

If the membrane potential is determined by the voltage difference between the inside and the outside of a neuron, and if action potentials produce electric fields strong enough that their effects can be measured outside the skull, then it just makes sense that a neurons firing an action potential should influence nearby neurons that they aren't connected to. I wonder if something like this was happening with the evolved circuit, like maybe the wires weren't perfectly insulated, so maybe the components that weren't connected to anything were affecting the rest of the circuit in this way? I.e. leaky electric fields had some affect on the rest of the circuit?
posted by Nquire at 8:39 AM on August 21, 2007


Malor, designbot: Damn Interesting covered that experiment in hardware evolution (performed in the mid-90s) a couple of months ago. The suspicion presented there was that the evolved program was taking advantage of magnetic flux interactions between the chips. An additional point of interest is that when the evolved program was copied onto another set of chips of the same model, it didn't work anymore, presumably because of slight deviations in the manufacturing or materials of each individual chip. So yes, certainly, that's an interesting example of an evolutionary approach taking advantage of whatever is offered, though in this instance, the evolved solution was so optimised that it was useless outside its exact environment, characterised by the particular configuration of chip instances. In that respect, it's probably not a great example of a sustainable evolutionary change, but I guess the main point (for me!) is that it's entirely possible for an evolved system to react to configuration changes that exist outside of the inputs that we might expect to exist. Outside of evolution working in surprising ways, however, this doesn't have too much to do with your intestine tasting (not that I'm suggesting you intended to push so bold a point, Malor!).
posted by bunyip at 8:49 AM on August 21, 2007


I hate it when people break out quantum consciousness BS. Individual neurons' activity are controlled by huge numbers of ion channels/transporters and ions. There is no way whatsoever that any known quantum effect could connect two neurons for a nontrivial length of time. Brains are not quantum computers, period. The only thing that quantum mechanics and consciousness have in common is that they are complicated and easily misunderstood.
posted by a robot made out of meat at 9:36 AM on August 21, 2007 [5 favorites]


How will this impact my plan to stay thin by cutting out my tongue?
posted by BackwardsCity at 9:37 AM on August 21, 2007


These cells aren't tasting anything just like retinal cells wired to your occulomotor (blink) reflex and vestibular system (balance) are not seeing anything. The system for image formation is entirely separate just like the system for tasting is entirely separate (and in another part of the body).
posted by euphorb at 10:20 AM on August 21, 2007


We've already seen similar behavior in the laboratory...evolved chips with apparently-disconnected components, that nonetheless require the components to be present to function. The chips work, but we don't understand why.

I think you're talking about an article by Clive Davidson about Adrian Thompson. I can't find the original source (or even a date) of that, so Thompson's page might be more directly helpful & relevant.

On preview: Bunyip has an updated version.
posted by Pronoiac at 10:27 AM on August 21, 2007


Metaformin+Coffee=Assplodes
posted by doctorschlock at 11:42 AM on August 21, 2007


Gut consciousness - In 1999, researchers in San Diego made an artificial neuron that worked with the real ones in a lobster's digestive system. So, you know, suck on that, defeatist quantum remote action people. (I know about this because it inspired Charlie Stross' Lobsters.)
posted by Pronoiac at 12:04 PM on August 21, 2007


BackwardsCity, ftw!
posted by oddman at 12:25 PM on August 21, 2007


a bit off topic, but... The gut consciousness idea makes me think of the link to migraines - Dopamine, a neurotransmitter(?) participates in controlling cerebral blood flow, nausea, all which malfunction during a migraine attack. Think also how our emotions - per jiiota above, or depression, excitement, etc - inform our gastro system.
posted by mightshould at 2:05 PM on August 21, 2007


So, after thinking about this over lunch, I wonder what it means for all those Atkin-diet people. Are low carb diets effective because you don't taste any sugar in your gut, so your insulin levels are different? Seems like a pretty far-reaching discovery.
posted by GuyZero at 2:38 PM on August 21, 2007


publius, I don't think miracle fruit would have much effect on the gut receptors. The active bit of the fruit is a protein, miraculin, which would probably get broken down by acid and peptidases before reaching the sugar receptors.

Incidentally, my miracle fruit seeds are not germinating. How disappointing.
posted by greatgefilte at 2:59 PM on August 21, 2007


GuyZero, speaking as one of those Atkins diet people (who is actually prediabetic and eating to the meter) I wondered exactly the same thing. This makes me wonder if you could block the receptor -- which would of course leave you unable to consciously taste sweetness, unless you could block it only in the gut and not your tongue -- if that would yet allow you to eat carbohydrates like potatoes, rice, and pasta which are a lot cheaper than my current diet and actually affect me worse than sugar.

OTOH I do use moderate amounts of artificial sweetener (Splenda and saccharine) and they don't seem to affect my blood glucose. So maybe not so much.
posted by localroger at 4:49 PM on August 21, 2007


Judging from the dual distress a plate of Beef Vindaloo can inflict, seperated by a span of approximately four hours, I would have guessed a smidgen lower.
posted by CynicalKnight at 7:03 PM on August 21, 2007


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