European researchers have demonstrated that 13 types of bacteria found in the gut are associated with depressive symptoms.
The Dutch scientists from Erasmus Medical Center Rotterdam and Amsterdam University Medical Center, working with UK colleagues at Oxford University, showed how gut bacteria may play a role in depression – a chronic feeling of sadness, emptiness or inability to feel pleasure – through production of neurotransmitters, such as serotonin and glutamate.
In the study, published in Nature Communications, the team specifically investigated the relationship between the composition and diversity of the gut microbiota with symptoms of depression from 1,133 participants.
Various bacteria identified showed a potential involvement in the way people produce neurotransmitters, particularly those linked to depression such as glutamate.
The researchers then replicated and validated these findings using data from another separate observational study.
Oxford-based co-author Dr Najaf Amin told medicalnewstoday.com the research team has ‘identified 13 types of bacteria [12 genera and one family] associated with depression.
‘Eggerthella, Hungatella, Sellimonas and Lachnoclostridium are more abundantly found, while Coprococcus, Lachnospiraceae UCG001, Ruminococcusgauvreauii group, Eubacterium ventriosum, Subdoligranulum, Ruminococcaceae (UCG002, UCG003, UCG005) and the family Ruminococcaceae were less abundant in individuals with higher symptoms of depression.’
She noted: ‘These bacteria are known to be involved in the metabolism of some key molecules including glutamate and butyrate through which these bacteria can influence depression.’
Dr Amin said such studies ‘are the first step towards understanding the pathogenesis, providing biomarkers and therapeutic targets for the disease. Since gut microbiome is primarily determined by lifestyle factors, diet in particular, once causality is established, the therapy would be as simple as modification of diet or the use of probiotics.’
She emphasised: ‘Depression is both an under-diagnosed and over- diagnosed disease. A biomarker will enable an objective measurement for depression, which is currently lacking – thus improving the diagnosis.’
Dr Amin also noted: ‘It is possible to alter the composition of these (populations of) bacteria through the use of prebiotics and probiotics.
‘For instance, the butyrate- producing bacteria can be altered by the consumption of high-fibre diets – for example, fresh fruits, whole grains and vegetables.
Georgetown University’s Professor James Giordano agreed, noting ‘an important message from this study is that gut health, via stability of the gut microbiome, is important to maintaining brain functions that are involved in thought, mood and behaviour.
‘The increasing knowledge about the gut microbiome and the gut- brain axis fortifies that the prudent use of pre- and probiotics can be of value in sustaining both gut and brain health.’
