Probiotics: is there any scientificially credible health benefit?

I know there are a lot of woo-woo claims about probiotics, but have there been any scientifically credible studies demonstrating any real benefit of consuming acidophilus culture & the like? Although it seems intuitively obvious, I’ve seen enough takedowns lately that I’m not sure it isn’t all 100% snake oil.

Curr Med Res Opin. 2014 Feb 26.
A critical appraisal of probiotics (as drugs or food supplements) in gastrointestinal diseases.
Passariello A, Agricole P, Malfertheiner P.

I just picked up some antibiotics yesterday and the attached paperwork suggested probiotics for diarrhea prevention.

What else is it claimed to do? I haven’t seen any woo associated with probiotics, unless you count Jamie Curtis and her “bowel movement cure-it-all” commercials, which doesn’t seem worse than any other advertiser exaggerations. But I don’t have my finger on the pulse of woo culture, I expect the dope to educate me.

CHeck out this previous thread on probiotics:

Frustratingly, I cannot find the article at all now, but just a week or two ago I skimmed something (probably on Medscape) that linked high levels of L. acidophilus with weight gain, and producing a certain type of intestinal gas. Whereas humans with anorexia tended to have different dominant GI flora, and, um, different gas.

On the other hand, feedlot cows are dosed with probiotics to enhance weight gain. This result may simply be demonstrating the counteracting effect of regular antibiotics leading to loose stools and subesequent weight loss, but I found it interesting. I can see the pop headlines a few months from now…“Yogurt INEFFECTIVE for weight loss!” :slight_smile:

I hate to post the above without the relevant cite, but maybe someone else saw it or can dig it up. It almost prompted me to start a thread here.

I certainly fart a lot less when I eat yogurt regularly. Don’t know about the gas distribution though.

I haven’t seen that study specifically, but I did bookmark a BBC article to use the next time I saw someone saying that caloric intake and exercise were the be-all-end-all when dealing with weight loss:

Neat article, thanks! I see you can obtain a culture of the organism mentioned, and it grows well on, basically, beef bouillon. :smiley:

Unless your gut bacteria can make you create more mass-energy than you consume, this is not relevant to the diet-and-exercise concept.

How is it not related?

They do, to some degree, actually do the exact opposite: more of these bacteria present (in these particular mice guts) prevents some of energy substrate consumed from being absorbed, and what is absorbed is handled in ways that are less likely to preserve or increase fat mass. That seems a pretty tight relationship to me.

Control over what fraction of what we eat gets converted into fat, what is passed out, what gets converted into other things that suppress further intake, and how energy is stored and utilized seems to be very relevant to the diet-and-exercise concept.

A throw-away line in the BBC bit jumped out at me

and got me looking for more. The fiber used was oligofructose, which is not actually digested by A. muciniphilia … the organism eats the mucin in the lining (and thereby somehow stimulates more production of it), not fiber. But somehow extra fiber (not beef bouillon) leads to the same end state: a thicker mucin layer; more A.muciniphilia; less energy substrate absorbed (in this particular model anyway); less inflammation; and regulation of pathways that lead to less consumption and less fat accumulation.

Which brings us back to a comment I had made in the previous probiotic thread. Our microbiota plays a key role in many ways but the hype of throwing some fairly arbitrary selection into our guts is somewhat akin to throwing healthy fish into a dead polluted lake. The bacteria, like the fish, are only one (albeit an important one) portion of a healthy functioning ecosystem. Providing the raw materials needed by the ecosystem is a more comprehensive solution. Fiber and resistant starches, from vegetables, fruits, and whole grains, both soluble and insoluble, feed the complex ecosystem, and is a much better way to create a healthy and resiliant microbiome than throwing probiotics into a hostile environment. The documented benefits of probiotics so far are limited (and extrapolating from this particular mouse model to humans is a few steps more than is currently justified) but the benefits of a nutrition plan that feeds the good bacteria is very very solid.


Oligofructose supplementation in overweight and obese human adults led to modest weight loss and improved glucose regulation independent of other lifestyle modifications. The article had posited some ghrelin and PYY mechanism but possibly A. muciniphilia is involved …

High natural sources of oligofructose includes sunchokes and chickory root but too much too fast can cause bad gas with some gas pains too.

My Doc is an Osteopath and a Dr. of traditional Chinese medicine, she knows woo better than anybody so I was disappointed when she told me I was wasting my time taking probiotics, that, aside from the too weird world of fecal transplants, it’s not feasible to supplement such a complex system.

One thing I don’t get (and don’t like) about probiotics is they only seem to measure doses by counts, while it seems the strain of bacteria is much more important.

My aunt was recommended probiotics by a gastric specialist, who happened to sell them at a huge markup. It’s people like this that give medicine a bad name.

I always was a bit leery of the probiotics preparations. Yogurt often seems to be involved somehow and I’ve always been suspicious of that food stuff. Also, probiotics substances seem to have been added shortly after the ‘color cleanse’ people rattled their cages (is this the Jamie Lee Curtis’ reference?) which I very much doubt to have any medical validity (I have had my colon cleansed several times and watched movies of the inside of it. There certainly was no waste embedded on the lining).


You’re taking the diet-and-exercise concept too far. It is a proof that it’s always possible to lose weight, nothing more, and it only gets used as much as it does because there are invariably people in any weight-loss thread who claim that they have “tried everything” but have a “condition” (thyroid, joint problems, etc.) which means they couldn’t lose weight if they were placed on a starvation diet. Diet-and-exercise simply says “That’s physically impossible, start talking sense or take a walk.”

Your (much more interesting, I might add) points are useful when talking to people who understand basic physics and have admitted that the laws of thermodynamics and mass-energy conservation apply to living human beings.

Then again, the microbes in a ruminant’s GI tract help the host animal extract more calories from the same amount of food. Granted, humans don’t have the specialized anatomy for this, and I’ve never heard of GI bacteria in humans breaking down cellulose, but I wouldn’t go so far as to say that it’s impossible for gut bacteria to help a human digest food more efficiently or more completely.

It’s been a while since I listened to the relevant episodes, but the podcast This Week in Microbiology spends a fair amount of time talking about the gut microbiome and probiotics, and these are actual microbiologists discussing current scientific papers rather than woo-peddlers. This episode is the only one I’ve listened to that also turned up when when I searched for “probiotics,” but I’m pretty sure they talk about probiotics in particular in many of their episodes about the gut microbiome in general.

Interestingly, it seems like most of the effects of probiotics are related to the immune system rather than digestion, with the general effect of reducing inflammation throughout the body. Also, in keeping with what Dseid said, the effects of probiotics are generally transient, requiring you to keep taking them if you want to keep feeling the effects. That sounds really convenient for the probiotics industry, but them’s the breaks if you go by the science we have today.

Yet the comment it was in response to a statement about those who claim that “caloric intake and exercise were the be-all-end-all.” The be-all-end-all. Not claiming that it was not possible to lose weight.

What happens so often on these boards regarding diet is that two crowds talk past each other, hearing and often responding to what is not actually said. Virtually no one takes the position you describe but one group is constantly arguing against that simplistic strawman. The other side hears others as if they are claiming it is simple and easy, just eat less and exercise more, and responds to what they hear as a lack of understanding why the human machine is a bit more complicated than a gas engine, which perhaps is appreciated more by the other side than how it is heard.

It is about calories and it is more complicated than that alone. Everyone can lose weight if they eat little enough and bodies of those who are obese function to make it difficult to lose substantial amounts of weight (let alone fat alone) and even more difficult to maintain the loss. Different people do have different predispositions to becoming obese once in the context of our modern obesiogenic environment … based on genes and history, going back to prenatal environment and possibly even before. It is simple (eat less than you burn) and both complex and difficult (based on brain wiring, gut flora, etc.)

To state that diet and exercise is not the be-all-end-all is accurate; to state that diet (better stated “nutrition”) and exercise is the best we can do and will have highly significant impacts on health outcomes even if the weight outcome is only modest, is also accurate.

Max it is not only not impossible it is well established as a matter of experimental fact.