Hi Theresa,
We can't always trust what we read in Wikipedia, because anyone can write that information and edit what others write. And if a topic is poorly understood, or if it states an incorrect (but popular) viewpoint, the author can get away with murder, because the odds are good that no one who actually knows better is likely to ever see it, let alone take the time to correct it. Can you picture a busy GI doc taking the time to even read, let alone actually correct the mistakes in a Wikipedia article?
That author has a vivid imagination.
And inaccuracies, exaggerations and flat out misrepresentations seem to be more common in articles about gut bacteria, than most other topics, because it's such a poorly-understood topic, and everyone seems to be searching for more ways to rationalize the fact that we are stuck with being parasitized by the little pests, so they surely must be a good thing.
I really don't feel up to debunking that article (the flu is rough this morning), but if I don't do it, it won't be done.
Duty calls, so here goes.
The bicarbonate in the colon is there to facilitate the absorption of electrolytes, not vitamins.
Bicarbonate secretion: a neglected aspect of colonic ion transport.
People tend to write all sorts of glowing reports (mostly wishful thinking) to exonerate gut bacteria, and promote probiotics, but the reality of the matter is that gut bacteria contribute such a small amount (for our benefit) that it can safely be considered to be negligible. If someone is actually expecting gut bacteria to supply any significant amount of vitamins for them, that person would be the epitome of "The Eternal Optimist". Yes, gut bacteria may produce a significant amount of certain minor vitamins, but they surely do this for their own benefit, not ours. Of course the author conveniently fails to mention that, and he also fails to mention that those vitamins (that are available right there in the biofilms where they are much more readily available to bacteria, than to us) can come in very handy for malnourished pathogenic bacteria who could benefit from a little boost to get them started on a path of destruction. Bacteria need vitamins too, so if we get any leftovers, we're lucky. And remember that biofilms are almost impenetrable for most antibiotics, which suggests that they might be impenetrable for most other purposes also, so we might never have access to more than tiny traces of those vitamins.
Is there actually any valid evidence that the human colon is capable of absorbing vitamins produced by bacteria? Some people probably assume that just because gut bacteria can produce vitamins, we will automatically absorb them (because the small intestine is capable of absorbing all sorts of things). But that's not necessarily true for the colon. Why would bacteria be so willing to share their hard-earned vitamins with us? Oh yeah, I forgot — because of the "Lassie syndrome" described in the second paragraph after the quote, below.
They are also involved in the production of cross-reactive antibodies. These are antibodies produced by the immune system against the normal flora, that are also effective against related pathogens, thereby preventing infection or invasion.
Really? Man, that is one slick way to rationalize the fact that in some cases, our so-called "good" gut bacteria are suspected of sometimes triggering IBDs.
Claiming that "good" gut bacteria promote the production of antibodies in order to provoke the immune system into attacking any "bad" bacteria that might happen to be around (and causing our immune system to attack our gut, in the process) is downright hilarious. Triggering an IBD in order to get rid of a few pathogenic bacteria could hardly be considered a fair trade. With friends like that, who needs enemies? That's like burning down the barn in order to get rid of the rats. Yes, it's effective, but totally unjustified.
If the gut were a TV show from the early days of television, those bacteria would probably all be named "Lassie", because everyone seems to think that they are so eager to come to our rescue.
(Everyone except me, of course).
A mucus layer protects the large intestine from attacks from colonic commensal bacteria.
That just suggests that the gut was designed to function without bacteria, because a layer of slime can hardly be considered to be reliable protection against pathogenic bacterial activity. If they are going to attach to the wall of the gut, they have to attach to the cells of the mucosa, not the mucus. (How would they possibly attach to mucus?) That mucus is like a continuously-flowing, slow-moving river, and it tends to move downstream with the stool. The mucus is there to preserve moisture at the surface of the mucosa, to protect the mucosa from caustic chemicals that might be in the fecal stream, provide lubrication, and facilitate motility. Remember, research shows that fiber promotes motility by tearing the cells in the mucosa in order to promote the production of more mucus.
I realize that my campaign against all of the many kazillions of "gut Lassies" is almost surely going to fall on mostly deaf ears, but as I've pointed out before — those little buggers have some of the best lobbyists in the business, and none of them are averse to stretching the truth as the default option. And even the quote you listed admits that they probably cause IBDs. IMO, nothing that they could do that could even remotely be somehow misconstrued as a benefit to us, could possibly justify the triggering of IBDs.
May a teeny-tiny bird of paradise fly up their little noses (as if they had noses).
Tex
