Can Probiotics Improve Your Mood?

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Written by Consensus
7 min read

Can probiotics improve your mood?

Check out this answer from Consensus:

Probiotics appear to have a positive impact on mood and depressive symptoms, particularly in individuals with mild to moderate depression and those with Major Depressive Disorder. While the effects in healthy individuals are less pronounced, there is evidence supporting the role of probiotics in improving overall psychological well-being and reducing stress. The mechanisms behind these effects likely involve changes in gut microbiota and related biochemical pathways. Further research, especially in clinical populations, is needed to fully understand the therapeutic potential of probiotics for mood improvement.

The potential of probiotics to improve mood and alleviate symptoms of depression and anxiety has garnered significant interest in recent years. This interest is driven by the emerging understanding of the gut-brain axis, which suggests that gut microbiota can influence brain function and mental health.

Key Insights

  • Probiotics and Mood Improvement in Healthy Individuals:
    • Probiotics have shown to improve mood and reduce stress in healthy older adults, with significant changes in gut microbiota and increased serum brain-derived neurotrophic factor (BDNF) levels.
    • Probiotic supplementation has been associated with improvements in mood, reduction in depressive mood state, anger, and fatigue, and better sleep quality in healthy volunteers.
    • A meta-analysis found that probiotics have a small but significant effect on reducing depressive symptoms and anxiety in healthy individuals .
  • Probiotics and Depression:
    • Probiotics significantly reduced depressive symptoms in individuals with mild to moderate depression, but had no significant effect on healthy individuals.
    • In patients with Major Depressive Disorder (MDD), probiotics led to significant improvements in depressive symptoms and sleep quality over an 8-week period .
    • Probiotic supplementation reduced cognitive reactivity to sad mood, which is a marker of vulnerability to depression, in non-depressed individuals .
  • Mechanisms and Biological Markers:
    • Probiotics may influence mood by altering gut microbiota composition, reducing inflammation-causing bacteria, and increasing beneficial bacteria .
    • Changes in the kynurenine/tryptophan ratio and tryptophan/branch chain amino acids (BCAAs) ratio were observed in patients with MDD, suggesting a biochemical pathway through which probiotics may exert their effects.

 

 

Can probiotics improve your mood?

Kate Secombe has answered Uncertain

An expert from University of Adelaide in Microbiome, Cancer

While there is a wealth of evidence connecting the gut microbiome and mood, there is less quality evidence to suggest that probiotics are a useful tool to actually modulate mood.

The gut and brain are known to be connected via a signalling system called the gut-brain axis. Alterations in the microbiome can change the signalling to the brain and vice-versa. A recent systematic review found that probiotics may be a useful adjunctive treatment for depression and anxiety, however another similar review had the opposite finding. There is no evidence to suggest probiotics have a positive effect on mood in people without cognitive.

The wide applicability of results in this field are limited due to small studies, a lack of long-term follow up and a lack of mechanistic insights. Additionally, as different studies use different types of probiotics, it is difficult to generate a broad understanding of what effects probiotics have on gut-brain axis signalling.

Probiotics are often made of specific strains of bacteria, which in contrast to faecal transplants, do not contain the broad diversity and inclusion of bacterial metabolites. This may therefore reduce the effectiveness of a probiotic on changing microbiome composition.

More research is required to fully understand how to best modulate the microbiome in a way that could improve mood.

 

Can probiotics improve your mood?

Bella Van Sebille has answered Uncertain

An expert from University of South Australia in Oncology

While there is increasing evidence that the microbiome impacts mental behaviours and conditions (e.g. depression), we are still a long way from probiotics being effective in treating such things. More research is needed into the efficacy of probiotics.

 

Can probiotics improve your mood?

Hannah Wardill has answered Uncertain

An expert from University of Adelaide in Gastroenterology, Microbiome

There are certainly studies that show associations between the type of bacteria in our guts and brain function. For example, people with depression have distinct microbial traits compared to people without depression. Similarly, in people who have had chemotherapy for cancer, the degree of microbial injury is also associated with psychoneurological symptoms. But, associations do not mean causation! In other words just because two things occur at the same time, they are not necessarily linked in a causal manner.

This is a very big challenge in the microbiome field because when we look at a cross section of people with a certain disease, we dont know if the disease caused the changes in the microbiome, or the microbiome caused the disease…. just like the chicken or the egg. In reality, it is likely that the communication between the gut and the brain is bidirectional.

Take for example when we get nervous or stressed…. many of us need often need to use the loo. Similarly, people with gastrointestinal diseases like inflammatory bowel disease, often show a higher incidence of psychological disturbance. Nonetheless, it is near to certain that the gut and brain are inexplicably linked, and the microbiota is likely to be involved in this process.

In terms of probiotics and brain function, it remains unclear. If discussing “healthy” people, there is no robust evidence to suggest that probiotics have no appreciable benefits in gut health, immune function or brain function. Often, adopting a healthy diet and exercising is more effective. In people with psychological symptoms, such a depression, it also remains unclear. A recent meta-analysis (a large study of already published data), showed that probiotics were unable to have any benefit for people with depression. However, when administered in conjunction with antidepressants they were shown to provide additional benefits. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6595633/

However, there is also conflicting data: https://pubmed.ncbi.nlm.nih.gov/29197739/ – this meta analysis showed benefits of probiotics in promoting mood.

So – the jury is out! It is also important to note that probiotics are increasing considered sub-par, with many being limited in the number of diversity of bacteria that they have – this is why they have such variable results in the literature. More recently, the use of faecal transplants has been suggested for depression management. Faecal transplants have a much higher density and diversity of bacteria as well as all of their metabolites (which have benefits of their own that bacteria cannot achieve alone). There is currently a trial being conducted on this topic https://pubmed.ncbi.nlm.nih.gov/29197739/ , so watch this space!

 

Can probiotics improve your mood?

In my view, this is an interesting topic that deserves far more research before we can draw a conclusion. Preclinical studies and several anecdotal reports in patients show that there could be a link between mental health (including depression and anxiety) and dysbiosis, and therefore probiotics (but also prebiotics, see this research) might be able to equilibrate gut microbiota, mucosal barrier and improve intestinal health. This may reduce the level of systemic inflammation that might contribute to mental disorders. However, good quality clinical studies are still scarce, with low number of patients, and many confounders.

The recent clinical trials do not show clear effects of probiotics intervention over placebo but acknowledge that subtle changes may be induced that are difficult to detect (see this research). Tools for studying these matters might not be ideal yet. Maybe big data analyses will be necessary to determine the best clinical use of probiotics (and probiotics) for each patient.

 

Can probiotics improve your mood?

Possibly, but only a small number of microbes show such effects. Most microbes we have studied have no effects on mood.

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