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Psychobiotics: what you need to know about the latest frontier in gut health

Probiotics that could help with how you feel? We're listening

Spend any amount of time looking into the world of gut health and you'll be struck by the reported links between your digestive system and your mental state.

Recently illuminated by a rapidly growing field of science, this biological phenomenon is known as the gut:brain axis – a phrase which refers to the way that your gut microbes (the bacteria that live in your digestive tract) seem to carry a degree of sway over how you feel.

What are psychobiotics?

This link has been indicated in a few ways, but let's take one example. A landmark 2013 study showed how healthy people given a specific probiotic experienced significant changes in their brain activity, including a reduced risk of developing a low mood, when compared with people given a placebo.

Naturally, these discoveries have galvanised a stack of new theories as to how interventions that target your gut could be used in improving your mental health.

‘Psychobiotics’ are one such concept. This is a cool-sounding name for a relatively simple idea: probiotics that might be given to people with the specific aim of improving their mental health. The term was introduced by a team of Irish scientists in 2013, with this same team more recently broadening it out to encapsulate some prebiotics (plant fibres that are a source of food for healthy bacteria in your gut, and which so help these bacteria to flourish.)

What does the science say about psychobiotics?

So, is there any merit to this idea? To find out, WH asked Dr Megan Rossi (@theguthealthdoctor), a gut health research fellow, dietitian and the author of Eat More, Live Well, for her thoughts. ‘There have been over 20 clinical trials looking at probiotics in mental health, specifically, for anxiety or depression,’ she explained.

That’s not to say, though, that firm evidence to support their use has been gathered. ‘There have been a number of positive studies which showed that probiotics may help with depression, but there’s also been a number of negative studies – that means studies that showed no benefit.’ More research, specifically more large scale human studies, are needed to confirm their usefulness (a number of these are currently underway.)

Eat More, Live Well (Paperback)
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From the science we do have, it looks likely that psychobiotics are more beneficial in a clinical setting: that means for people who have been diagnosed with depression, which is on the more severe end of the scale. When it comes to anxiety, the evidence we have right now does not suggest that psychobiotics have much of an effect.

Anything else that's important to know about psychobiotics?

It’s also true that the studies we do have used different types of bacteria in their work. This complicates things, because different strains, or cultures, do different things – this is the reason why most probiotic brands will shout about the specific strains they have in their formulas, say, Lactobacillus casei or bifidobacteria.

What we need, then, is further studies on those strains, or combinations of strains, which have thus far been shown to confer benefits, as well as diving into the impact of strains that have not yet been analysed, in this context.

The crux of the issue, then, is specificity. Dr Rossi notes that the state of someone’s mental illness is going to matter – someone who is hospitalised with depression is likely going to need different interventions to someone who is using antidepressant medication, but who is highly functioning and living a regular life.

Layer on the need to isolate the strains or blend of strains that have a meaningful impact, and you can see how tessellating this is going to be fiddly. Plus, everyone’s GM is unique. It’s not impossible that people would need bespoke psychobiotics – even with an understanding of the severity of someone’s mental ill health and the most beneficial bacterial strains for the condition they're living with.

So, what next?

Again, this is all pending the results of more large scale human studies, that show in granular detail what preparations of probiotics might work for which populations of people. Dr Rossi believes that, within the next 5 years, it’s probable that we’ll have good evidence to support specific types of bacteria helping with certain mental illnesses, which we’ll call ‘psychobiotics.’

These could be used in conjunction with existing mental health therapies, including targeting gut bacteria through a high-fibre, whole food diet that prioritises plants (an intervention that has been shown to have clinically significant results on people dealing with depression.)

Fine, but what should I do, right now?

If you are concerned about your mental health, then speak with your GP, or ring mental health charity Mind's infoline (0300 123 3393) to be signposted to more information.

In the meantime, if you want to support your gut to nourish your mind, as ever, remember to eat a diverse, whole food and plant-focused diet, make time to move your body, get enough sleep and relax your gut-brain axis through stress-relieving activities, like deep breathing, yoga and meditation.

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