There's No Evidence That Probiotics Do Good Things For Your Health

The terms probiotics and prebiotics are appearing on more items in supermarket aisles all the time. Both words, their placement and the products they adorn, imply they're good for you, that more of these bacteria will help you in some way. But there's actually scant evidence for such claims.

Yoghurt picture from Shutterstock

Let's start at the beginning: a probiotic is something full of bacteria expected to take up residence in your gut, while a prebiotic promotes the growth of already-present gut bacteria.

Before you buy probiotics, you need to know whether they survive the perilous journey through the stomach and into the lower gut. And whether the bacteria have a measurable impact on your health once they reach their destination.

Sadly, this information is not available because we haven't done the research to find out. But new European food regulations are starting to push manufacturers to provide evidence for probiotics' advertised health benefits.

What they're supposed to do

When you consume a probiotic, you're eating a particular strain of bacteria that you — and the product's manufacturer — consider helpful. Many bacteria are killed by the acidic conditions in the stomach but a small number survive and may make it to the lower gut — the colon or large intestine.

Once at their destination, these bacteria need to establish themselves. But it's a jungle down there, with many competing species of bacteria and scarce resources. In order to survive, new arrivals need food and this is where the prebiotics come in.

Prebiotics feed gut bacteria and are not usually digestible. One example of a prebiotic is a sugar contained in many beans called raffinose, which the gut is not equipped to use. It's the basis for the well-known — and entirely true — story that beans make you fart. Specifically, the bacteria in your gut that like raffinose also like to produce gas when they eat it.

Prebiotics nurture specific types of bacteria already present in your lower gut. As with the probiotics, the idea is that nurturing these bacteria and increasing their numbers will provide a health benefit.

Regulatory hurdles

Both probiotics and prebiotics are generally sold as food products. To put a health claim on a food label in Europe requires strict scientific evidence.

In 2006, the European Union adopted a new set of regulations that defined the terms probiotic and prebiotic as making specific health claims. The directive effectively acted as a ban on using these words on packaging because none of the products using the words has the evidence to back up their health claims.

To have these words on the labels of their products, manufacturers need to provide evidence that the bacteria survive the long journey through the stomach and into the lower gut. Importantly, they also need to show that once there, the bacteria have a specific action to enhance health.

The ban on using probiotic on packaging has been phased in over the last few years and has been upheld by EU courts. Products such as yoghurt and cheese can still be sold, but the regulations limit the health claims manufacturers can make on their labels.

What the European Food Safety Authority (EFSA) is looking for is a direct cause-and-effect relationship. To gather this type of evidence, you generally need well-funded, multi-centre clinical trials — and these haven't yet been done for many probiotics or prebiotics.

So many doubts

There are good reasons for the European ban. Consider a recent probiotic cheese that claimed to lower blood pressure. The EFSA found little evidence that edam-style cheese loaded with Lactobacillus plantarum helped maintain normal blood pressure, as it claimed.

In another recent case, the EFSA looked at the consumption of a combination of Lactobacillus rhamnosus and Lactobacillus paracasei. This mixture was supposed to improve intestinal regularity and fecal volume. Once again, the opinion of the EFSA was that a cause-and-effect relationship had not been established.

The ban has caused many manufacturers to cry foul, arguing that banning the terms probiotics and prebiotics hurts business and confuses consumers. Nonetheless, no products labelled as probiotics or prebiotics have yet been approved by the EFSA for sale in Europe, though several are still under consideration.

In Australia, probiotics and prebiotics are regulated by Food Standards Australia New Zealand (FSANZ). In answer to the increasing regulation in Europe, this body has recently adopted a framework for regulating health claims.

The framework is now similar to how the Therapeutics Goods Administration (TGA) regulates drugs. Despite this recent change, manufacturers are still allowed to use the terms probiotic and prebiotic on their packaging — though this may change.

That your gut bacteria are critical in maintaining your health is well established. But we don't know which bacteria are helpful and how they act. Until these questions are answered, probiotics and by extension prebiotics will struggle to fulfil their claimed promises. And manufacturers may need to learn to temper their language.The Conversation

Paul Bertrand is Senior Lecturer in School of Medical Sciences at RMIT University. Andrew Ball is Professor of Environmental Microbiology at RMIT University. Kate Polglaze is Associate Lecturer in Pharmaceutical Science at RMIT University.

This article was originally published on The Conversation. Read the original article.


Comments

    A doctor told me that probiotics are best consumed when you are taking antibiotics, so it balances out. There isn't really a big need for them outside of that scenario it seems, although it won't hurt you if you did take some.

      This is sound advice. There are some "reasonable" quality corroborating studies showing that probiotics reduce the duration/severity of the common antibiotic-related diarrhoea. A simple Google Scholar search will find them for anyone curious.

      An important point to make is that, while there is probably little to no benefit from taking probiotics at other times, there is no evidence of harm demonstrated thus far. And humans have been eating probiotic bacteria-laden foods for millennia. So at there worst, there's no danger whatsoever and it's down to choice.

      Personally, I quite like the slightly sour taste that live yoghurt has. It makes a welcome break from the over-sweet mass produced crap that masquerades as yoghurt but is actually a thickened, gelatin and sugar mush.

      Last edited 26/01/15 5:51 pm

        Is being out of pocket from buying crap 'harm'...?
        I'm referring more to the hideously expensive probiotic tablets here, rather than the yoghurt with live cultures which as you say is often different in other ways (flavour, texture, etc).

    I'm loving the fact that companies peddling these "natural remedies" are finally being forced to put up or shut up. The farcical alternative health industry have gotten away with it for way too long.

    I only ever take probiotics when I'm taking a higher than usual dose of antibiotics, as they make me sick. If I'm taking a regular dose I'm fine, and don't need the probiotics.

    "...But there’s actually scant evidence for such claims."

    In all due respect, bullshit. There is substantial evidence to the contrary of your claim. I really don't feel the need nor time to bother listing journal articles which you should know about considering your position. (xkcd has taught me about not wasting too much time with arguments on the internet).

    However, if you only allow multi-center trials as evidence, then you have a point but that is because you are stretching the meaning of scientific evidence to breaking point. It is equivocation to prove your point. Sure the gold standard is multi-center when performed properly and it rarely is and I've worked with some of the bigger pharma companies. However, that does not mean that all the other papers and research on probiotics is somehow not evidence. That is the bullshit in your argument. The types of studies that I'm talking about have been published in real journals by real scientists and is evidence. It just isn't unequivocal evidence or causative. But to not call it evidence is bullshit!

    Nonetheless, by using your equivocation about what evidence is then very little else will ever really be accepted as healthful expect for a pill because often the only people that can afford to publish absolute gold standard studies like the ones you are only accepting for your argument (conveniently) are those that can patent their product (eg. drugs and not pre-existing bacteria).

    Oh, how I wish I could be bothered taking on the specific and many spurious claims made in the above article but I really should go on and read something worth my time.

      There is certainly evidence that many of these strains of bacteria have beneficial effects when they take up residence in the intestines. The question is whether this is likely to occur when eating these foods in normal quantities.

        No need to eat in normal quantities. You just take for a few days to give the probiotics a chance to restore normal gut health.

    I'm not for a second suggesting that there isn't issue with some claims about probiotics. However, the material in this article is so out of line with evidence (and I note the academic titles of the authors) that they are extremely wrong about their conclusions drawn by the evidence. Their counter claims are as ridiculous as the fanciful claims of food companies about probiotics.

    The article above and its information is over-stretching to say the least.

      How's that "not wasting too much time with arguments on the internet" coming along Mr. BiggestCommenterOnTheTopicSoFar?

        Shhhhhhh.
        Didn't momma tell you. Don't feed the trolls.

    Just to play devil's advocate (much like helpful guest 'stephen'), it's important to note that the research you see here isn't necessarily all the research you need to see, or necessarily even as unbiased or conclusive as the article would make out to be.

    For example: http://www.gizmodo.com.au/2014/12/cruise-ships-dump-a-billion-gallons-of-sewage-in-the-ocean-every-year/ - an article written with alarming pictures and 'facts' based entirely on a PR piece distributed by a 'friends of the earth' group.

    Read the comments in that article for industry folks adding much-needed counter-point perspective.

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