We use cookies to give you a better experience. Carry on browsing if you're happy with this, or read our cookies policy for more information.

Skip main navigation

Do psychobiotics work?

In this video, we discuss some studies that investigated the use of pre and probiotics on our mind
7.4
Hello everybody. In the previous videos and articles we’ve seen that there is a link between our gut and our brain – more importantly, we have seen that there is a link between our gut microbiome and our health, both psychological and physical. One approach used to verify these connections is to modify the microbiome, observe the changes that follow the intervention and to draw a connection between the cause and the results obtained. Of course, when scientists observe positive effects, the next step is to try to translate the results obtained in animal models, or in cell cultures, to humans. Broadly speaking, there are two classes of foods and supplements that are sold for they
58.6
beneficial effect on our gut bacteria: probiotics, which we already discussed, and prebiotics. Prebiotics are substances that encourage the growth and the activity of beneficial organisms, and is usually used when talking about compounds that affect the gut microbiome. We discussed one study showing the effects of prebiotics on the human brain in the last video, but is there more evidence that modifying the microbiome, using either approach, can improve our mental health? Well, most studies actually assessed the effects of pro and prebiotics on digestive system disorders, or on allergic syndromes, and they found positive effects on some forms of diarrhea or on the symptoms of irritable bowel syndrome.
117.1
A few studies, however, tried to replicate in humans the studies investigating the neural and psychological effects of probiotics on mice. As the enthusiasm for this new field started to grow, a new word was coined to indicate those probiotics that could have
137.4
positive effects on our mood and cognition: psychobiotics. In one study investigating psychobiotics, researchers recruited 55 healthy volunteers for a clinical trial, giving half of them a placebo and half of them a specific probiotic formulation. This study found a positive effect of the probiotic formulation in anxiety, depression and other symptoms of psychological distress after one month of treatment. Two years before, another study investigated the effect of a prebiotics whose name you might recognize – lactobacillus casei shirota – on the depressive and anxious symptoms of patients suffering from chronic fatigue syndrome.
188.1
This study, too, found a significant decrease of anxiety symptoms in patients that took the probiotic, as well as an increase of the number of ‘good’ strains of bacteria in their digestive systems. There are other, more recent clinical studies But if we just look for studies that have published in scientific journals, we run into the risk of only seeing what works, and not what does not work – studies that find nothing usually don’t get published!
223.6
So, we can try another approach: clinical trials – the more rigorous experiments to assess whether a treatment has a significant effect or not – are often registered on databases even before they start. It is then easy to see which ones have been discontinued, which ones have been completed and what are the results. As of mid 2019, there are 10 active clinical trials that investigate probiotics or prebiotics in the treatment of depression, five that investigate the treatment of anxiety, two that focus on the treatment of obsessive- compulsive disorders, and at least two that deal with cognitive impairment.
273.5
To put these numbers into scale, at the moment there are about 300 active trials investigating pre or probiotic, and more than 1000 trials on depression. It seems then that while psychobiotics are a small, but not insignificant, part of the probiotic trials, they are only a tiny percentage of the broader field of the studies assessing new treatments for psychological illnesses. An intermediate, and very important, stop on the road to understanding whether psychobiotics are effective is to understand their possible mechanisms of action. As of today, it is still unclear, but given their effects on asthma, eczema and other allergic symptoms, it is possible that the immune system plays a role in the interaction between the microbiome and the brain.
334.5
This would bring us back to our lecture on inflammaging, and it would be another step into painting a big picture that puts together our gut, the food we eat and their consequences on our body and on our mind.
Are there interventions that can improve our mind by enhancing our gut microbiota?
In this video, we explore the results of some studies that investigated this topic in humans, trying to find another piece of the microbiota-brain-gut puzzle, and trying to understand whether the claims and generalisations around us are true.
This is the last video of this course and it brings us almost to the end of our discussion of the microbiota and the brain.
We hope that you have found this activity to be useful and interesting!
This article is from the free online

Food for Thought: The Relationship Between Food, Gut and Brain

Created by
FutureLearn - Learning For Life

Our purpose is to transform access to education.

We offer a diverse selection of courses from leading universities and cultural institutions from around the world. These are delivered one step at a time, and are accessible on mobile, tablet and desktop, so you can fit learning around your life.

We believe learning should be an enjoyable, social experience, so our courses offer the opportunity to discuss what you’re learning with others as you go, helping you make fresh discoveries and form new ideas.
You can unlock new opportunities with unlimited access to hundreds of online short courses for a year by subscribing to our Unlimited package. Build your knowledge with top universities and organisations.

Learn more about how FutureLearn is transforming access to education