How probiotics can influence brain function

How probiotics can influence brain function

Dr Peter French2 comments

Scientists from the California Institute of Technology (Caltech) and the University of California Los Angeles (UCLA) in November 20161 have demonstrated that the health of the gastrointestinal tract plays a key role in regulating healthy brain function. In a paper in the very prestigious international peer reviewed scientific journal Cell, the researchers reviewed 194 published papers that provide evidence for gut bacteria being “integral contributors to development and function of the nervous system and to the balance between mental health and disease”.

 They presented evidence that showed the gut microbiome (the bacteria that reside in the gastrointestinal tract of humans) and/or probiotics could play a key role in a range of neuropsychiatric conditions, including depression and anxiety, autism spectrum disorder, schizophrenia, Parkinson’s disease (PD) and Alzheimer’s disease (AD) . This was further supported by researchers from the Chinese Academy of Sciences who provided evidence for the role of the microbiome, and, by implication, probiotics, in dementia2.


The role of the gut microbiome and probiotics in human health.

The authors acknowledge that the gut microbiome plays a significant role in the wellbeing of its host. Consumption of probiotics supplements the gut microbial population with a specific microbe, either transiently or permanently, and can change the microbiome profile and function, as well as interact with the host to produce a range of beneficial health effects. The effect of probiotics on immune health was clearly stated by the researchers: “Research in animal models and humans has inextricably linked gut bacteria to the development and function of the immune system. The presence of entire immune cell types requires the microbiome, and specific microbes have been discovered that either promote or ameliorate immunologic disorders such as type 1 diabetes, asthma, and inflammatory bowel disease.”

"Research in animal models and humans has inextricably linked gut bacteria to the development and function of the immune system" 

In both papers the authors predominantly focused on evidence for the role of the gut microbiome in nervous system disorders.


Evidence for the ability of probiotics and the gut microbiome to influence mood:


  • A study in healthy volunteers who consumed a fermented milk product containing probiotic bacteria showed alterations in brain activity during an attention task, in brain regions that control processing of sensation and emotion, in comparison to a control group who consumed a milk drink without probiotic bacteria.

  • Another study in humans associated the gut microbiome in IBD with stress disorders.
  • Gastrointestinal symptoms are associated with depression, with around 20% of patients reporting such symptoms.
  • The composition of the gut microbiome in major depressive disorder (MDD) patients is significantly different from that of healthy controls3. When fecal samples from MDD

 "Mouse and human studies provide tantalizing suggestions that the microbiome may play an active role in driving depressive-like behaviors suggesting potential new avenues for therapeutic development"

  1. Sharon G, Sampson TR, Geschwind DH, Mazmanian SK. The Central Nervous System and the gut microbiome. Cell 2016; 167: 915-32.
  2. Alkasir R, Li J, Li X, Jin M, Zhu B. Human gut microbiota: the links with dementia development. Protein Cell 2016; DOI 10.1007/s13238-016-0338-6
  3. Significantly more Actinobacteria and less Bacteroidetes in MDD-associated microbial populations



patients and controls were transplanted to mice, the recipients of MDD samples exhibited much more depressive-like behaviour compared to controls


Evidence for the role of probiotics and the gut microbiome in autism spectrum disorder (ASD):

  • The gut microbiome of ASD patients has an increased abundance and diversity of “unhealthy” bacteria4.
  • The gut microbiome of ASD patients often lacks probiotic bacteria.

  • Gastrointestinal symptoms such as diarrhea are significantly more prevalent in children with ASD.


Evidence for probiotics and the gut microbiome in dementia

Dementia is a syndrome that affects memory and other cognitive functions to the extent that it interferes with daily function. There are many conditions that can cause dementia, including neurodegenerative disorders [e.g. Alzheimer’s disease (AD) and Parkinson’s disease (PD)], cerebrovascular disease, brain injury, and certain infections. There are several studies cited by the authors that imply a role of the gut microbiome in AD and PD:


  • Individuals afflicted with PD display significantly different fecal and mucosal microbial populations:
    • There are increased numbers of tissue-associated E. coli in the gut of PD patients compared to healthy controls,
    • Furthermore, short chain fatty acid (SCFA) concentrations in feces from PD patients are decreased as compared to controls. SCFA are produced by bacterial fermentation in the gut, and are needed for normal nervous system development.


    • Recent evidence suggests that molecules from bacteria present in the microbiota can trigger autoimmune responses that promote neurodegeneration during AD and PD.
    • There are marked differences in the composition of the gut microbiome between AD mice and healthy mice and strongly indicated that a distinct microbial population in AD mice may play a role in the development of the disease.



    From their extensive review of the literature, the American group conclude that there is a growing understanding of how different gastrointestinal tract microbial populations, beneficial or pathogenic, regulate the nervous system in health and disease. They contend that, “this holds promise in the diagnosis, treatment, and prevention of some specific neuropathologies. Determining how a microbiome, changing with Westernisation and other environmental factors, impacts a human population with growing rates of neurodevelopmental disorders and increasing life expectancy represents an urgent challenge to biomedical research and to society.”

    The Chinese group reports a similar result. They propose that modulation of the gut microbiota (by probiotics or other dietary intervention) is a growing area of interest for the pharmaceutical and functional food industries, with the goal of decreasing the incidence of diseases associated with Westernisation and longevity, including Alzheimer’s disease.

    4 These were reported to include Clostridia species, non-spore-forming anaerobes, microaerophilic bacteria and Sutterella. 

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    The gut and hypertension - how probiotics can help

    The gut and hypertension - how probiotics can help

    Dr Peter French2 comments


    In studies published in 2015 and recently (October 31, 2016), researchers at the University of Florida in the United States reported on the role that probiotics could play in reducing elevated blood pressure1,2.

    It is well accepted that the gut microbiota (the trillions of bacteria, both good and bad, that live in your gastrointestinal tract) plays an important role in supporting and maintain a healthy immune system. In fact, the GI tract is commonly referred to as an essential acquired organ because its composition and richness are constantly adapting to the challenges presented by the environment or by the host, such as age, diet, lifestyle modifications and disease states.

    Changes in gut microbiota have been related to chronic inflammatory diseases, such as asthma, eczema, allergies, inflammatory bowel disease, and infectious diseases.

     However, the researchers found data from clinical trials to suggest that the gut microbiota may also play a role in the development and maintenance of heart disease and metabolic disorders including obesity, diabetes, and metabolic syndrome.

     Adult gut microbiota is diverse; it is made up of trillions of microorganisms but a delicate balance in its composition is key in maintaining good health; any disruption of this balance could lead to devastating physiological consequences.

     They quoted the work of a group3 who in 2014 looked at several clinical trials that have been conducted over the past few years examining the effect of consumption of probiotics on blood pressure. Their combined analysis of nine randomized clinical trials with 543 participants in total showed a significant decrease in both systolic and diastolic blood pressure in patients who consumed a daily dose of live probiotic organisms. This evidence indirectly suggests that gut microbiota may play a key role in the control of blood pressure and that any change in microbiota composition or imbalance may potentially result in hypertension.

     Furthermore, the researchers went on to conduct their own study, and their results were consistent with previous clinical studies, showing that a shift in the gut microbiota was associated with higher blood pressure.

     In a recent study (October 2016) the researchers concluded that a dysfunctional gut microbiota is associated with gut pathology, dysbiosis, and inflammation, and plays a key role in hypertension. “Thus, targeting of gut microbiota by innovative probiotics, antibiotics, and fecal transplant, in combination with current pharmacotherapy, may be a novel strategy for hypertension treatment.”

    • Yang T. et al., Gut dysbiosis is linked to hypertension. Hypertension 2015; 65:1331-1340
    • Santisteban MM, et al., Hypertension-linked pathophysiological alterations in the gut. Circ Res 2016 Oct 31.
    • Khalesi S, Sun J, Buys N, Jayasinghe R. Effect of probiotics on blood pressure. A systematic review and meta-analysis of randomized, controlled trials. Hypertension 2014; 64:897-903

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    Hay fever and PCC®

    Hay fever and PCC®

    The Bioxyne Team1 comment

    Olia Gozha

    With Spring on the way, while most of us look forward to warmer weather and longer days, those of us who suffer from severe symptoms of hay fever are less excited. Many dread the onset of itchy eyes, runny noses and constant sneezing. Some turn to over the counter drugs to dry up their symptoms. But there may be a better way.

    With the increased knowledge that out gut microbiome is critical for a range of health conditions, including our immune system, researchers have focused on the use of probiotics – good bacteria – to assist with our gut and immune health. And now there is evidence that probiotics could alleviate the symptoms of hay fever. There are at least 18 studies that show that some probiotics can produce a significant improvement in symptoms and quality of life in hay fever sufferers. How they do this appears to be by boosting what is called the Th1 immune response.

    A clinical study on babies with moderate to severe eczema, which, like hay fever is a response to an environmental allergen, showed that Bioxyne’s probiotic, called PCC® (A Lactobacillus strain) boosted the Th1 immune response and significantly improved the symptoms of eczema in comparison to a placebo control.

    PCC® therefore is likely to have a similar effect on hay fever symptoms. And it has been shown to boost gut health as well! You don’t get that benefit with the OTC hay fever drugs!


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    What long-distance runners need to know about PCC®

    What long-distance runners need to know about PCC®

    The Bioxyne Team

    Bruno Nascimento

    Endurance training is excellent for heart health but it does take a toll on the immune system.

    It has been known since at least 1993 from a range of studies that unusually heavy acute or chronic exercise is associated with an increased risk of upper respiratory tract infections (URTI).

    The clinical data supports the concept that heavy exertion increases an athlete's risk of URTI because of negative changes in immune function and elevation of the stress hormones, epinephrine, and cortisol.

    The Bioxyne team suspected that PCC would be of benefit to athletes and their compromised immune systems when our own preclinical studies showed that PCC® preferentially bound to the Peyer’s patches in the gut. Peyer’s patches is immune tissue in the gastrointestinal tract that plays a key role in mucosal immunity.

    We proposed, therefore, that PCC® may boost the mucosal immune system, providing protection against respiratory tract infections leading to cold and flu symptoms.

    In order to examine the ability of PCC® to boost the mucosal immune system in humans, we designed clinical trials on long distance runners and other elite athletes, who are known to be more susceptible to contracting URTIs than the general population.

    To carry out the study, we took 20 male elite distance runners in the height of winter. They were training to compete in events ranging from 800 metres to the marathon (42.2 km).

    After recruitment, our athletes completed an initial treatment month (28 days)receiving either L. fermentum VRI-003 (PCC®) or placebo. A washout month followed the completion of the first treatment month. Previous studies have shown that it typically takes a probiotic bacteria 3–8 days to pass through the gastrointestinal tract. We then swapped what our participants were taking, so that those receiving PCC® as the first treatment received the placebo as the second treatment and vice versa. The athletes were monitored for an additional fortnight (referred toas ‘‘follow-up’’) after completing the second treatment. During each treatment month subjects were required to take three capsules, twice daily.

    Athletes maintained daily diaries recording symptoms, days, severity and medications.

    The most important finding of the study was a significant reduction in the number of days of respiratory illness symptoms, and a trend towards a lower severity of illness, during PCC® treatment compared with placebo.

    It’s clear from the clinical data that elite endurance athletes can benefit from taking PCC® when undertaking intense training for competitions, because it improves resistance to common illnesses associated with the increase in stress hormones at that time, which will ultimately impede their training and performance.

    The study authors noted that “different strains of L. fermentum have different immune-stimulating ability” - PCC® it seems is particularly effective at boosting mucosal immunity in elite athletes.

    Learn more about the study here.

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