gut bacteria and brain effects

Professor Ted Dinan is Professor of Psychiatry and a Principal Investigator in the Alimentary Pharmabiotic Centre (APC) at University College Cork. His primary research focus is on immune and endocrine aspects of depression and irritable bowel syndrome. Professor Ted Dinan’s research, funded by Science Foundation Ireland, is looking how gut bacteria can balance brain development and function.  Gut bacteria produces chemicals that the brain depends on, such as serotonin produced from tryptophan, which regulates mood.  If our brains do not store amounts of the chemicals that we need, our mood and mental health is affected.  According to Professor Dinan:

“In our research, we have shown that if we give one particular probiotic – Bifidobacterium infantis (Alflorex), it can significantly increase the blood levels of tryptophan.”


His role in the Alimentary Pharmabiotic Centre has led to development of the idea of “psychobiotics.” A Psychobiotic is defined by Dinan and his team as:  a “live organism that, when ingested in adequate amounts, produces a health benefit in patients suffering from psychiatric illness”. Psychobiotics are essentially probiotic gut bacteria, however Dinan’s research is showing that probiotic usage has to be very specific and in reality he estimates that “less than 5 per cent of probiotics may have psychobiotic activity.”

“Many probiotics that are currently available, despite the name, have no health benefit and certainly no benefit from a mental health perspective,” according to Prof Dinan.

However some probiotic bacteria may be helpful in treating stress-related disorders and other mental health conditions and it is in this area that Dinan is focusing research. The APC, with foundation industry parents Alimentary Health, has already developed several targeted psychobiotics as “medical foods”.

PrecisionBiotic​ containing a unique culture of Bifidobacterium infantis – namely Bifidobacterium infantis 35624 (BIFORTIF) developed for the relief and management of irritable bowel syndrome, is sold in Ireland and UK as Alflorex and as Align, in the US and Canada.

Dinan says:

“Psycobiotics are unlikely to replace anti-depressants in patients with severe forms of depression or anxiety. However, they offer enormous potential in patients with milder conditions.

“Clinical evidence shows that probiotics can work on IBS, we don’t yet have good clinical trials for use in depression.”

However Professor Dinan hopes that with continued clinical research, probiotics will be used as a treatment for anxiety and depression.

Research on gut bacteria is also showing that Lactobacillus rhamnosus has effect on anxiety. Emily Deans M.D. writing in Psychology Today on the brain gut connection says:

Gut-depression links are already well known – psychological stress in humans is associated with reduced fecal Lactobacilli, and individuals with major depressive disorders had some fragments of gut bacteria inappropriately floating around in their blood, suggesting the presence of leaky guts. One small study showed that giving people a prebiotic that favors Bifidobacteria reduced anxiety in patients with irritable bowel, and another 2 month placebo-controlled study showed that lactobacillus treatment reduced anxiety (but not depression) in people with chronic fatigue. (Source: Psychology Today The Parasite Ate Your Depression)

For a more detailed overview on the exciting research now being done on the brain gut connection listen to Professor Ted Dinan speaking at the University of Maryland School of Medicine conference on Human Microbiome Science: Vision for the Future:

Read more on Professor Dinan’s work:



A gut feeling: Could depression be prompted by what you eat?

Scientists link autism with lack of gut bacteria | Irish Examiner

UCC scientists find that “Psychobiotics” offer potential in improving mental health.