Our gut microbiota (gut flora) is a complex community of organisms and bacteria working together to maintain dynamic ecological balance. There is close to one trillion bacteria that live in the gut and are not only important in proper gastrointestinal health and digestion function, but also play a key role in brain development and function along with behaviour, cognitive and emotional processing.
The gut has the ability to communicate to our brains and central nervous system through the gut-brain axis.This axis is not fully understood yet, however large research is going into the area and new insights are rapidly developing everyday.
The emerging link between our gut and brain is regarded as a shift in what was once normal diagnosis and treatment of neurological disorders such as anxiety and depression.
The gut-brain axis: a bidirectional pathway
Since its first discovery in animal trials in 2004, more and more human trials have found a clear link to optimum gut health and improved brain function. Communication between the gut microbiota and the central nervous system occurs through a series of complex pathways located within the body that involve several different neurotransmitters and receptors working synergistically. Studies have shown that any alteration to our emotional state can adversely affect our gut microbiota function, which in turn can allow non-beneficial bacteria and other nasties into the nervous system directly affecting our mood and behaviour. Additionally any imbalance in our gut microbiota can alter our immune systems and inflammatory responses which has potential to have ill effects on the body as a whole.
The importance of probiotics
The core stability of our gut microbiota remains fairly stable during our adult life; however, lifestyle, stress, drugs and infection can all cause an imbalance. The use of probiotics reintroduces the beneficial bacteria that may have been killed off from the result of the above factors. Studies are now showing us probiotic use can be beneficial in restoring missing microbiota, leading to reduced inflammation, strengthening our intestinal barrier along with producing and influencing key nervous system transmitters and pathways that impact on gut brain functionality.
Which probiotics are most beneficial?
Not all probiotics are created equal, with different strains showing to more beneficial than another in helping treat different levels of disease states. Clinical trials have shown the two strains Lactobacillus helveticus and Bifidobacterium longum to be the most beneficial in helping to reduce symptoms associated with stress and mood disorders, such as anxiety and depression. Of importance, these trials are also showing subjects are not only improving behaviours towards obsessive compulsiveness, anxiety, paranoid ideation and heightened perceived stress, they aren’t showing any adverse effects to the probiotics that can sometimes be associated with pharmaceutical medication, such as learning or memory difficulties.
With more and more studies comes more and more information on other strains of probiotics that are beneficial to our overall health. L.acidopilus, L. casei and B. bifidum have shown to significantly reduce symptoms of depression in patients with major depressive disorder, while increasing antioxidant levels and decreasing serum insulin levels. B. bifidum, B.lactis, L. acidophilus, L. brevis, L. casei, L. salivarius and Lactococcus lactis have all been seen to improve subjects with negative thoughts. Other strains B. lactis and L. rhamnosus are beneficial to improving gut transit time, overall microbiota levels and cellular immunity. With all three being important for our gut-brain axis communication and function.
Psychobiotics for the gut-brain axis
A healthy digestive system is crucial in aiding our mood and cognitive function. Most importantly in the early and late stages of life, a proper balance of microbiota can have a profound impact on brain function and neurological health. Evidence is continually growing on the studies of the gut-brain axis, showing probiotics potentially working as psychobiotics due to their benefits towards our mental health in improving conditions such as anxiety and depression.
Reference: HealthFx June 2017