Link found between gut bacteria and stroke

London: Imbalances in the good and bad bacteria in the gut of the elderly causes inflammatory responses that are linked to age-related conditions such as stroke, dementia and cardiovascular disease, a research has showed.

The findings showed that chronic inflammation causes imbalances, or "dysbiosis" of gut bacteria that results in "bad" bacteria being more dominant than "good" bacteria.

An overgrowth of bad bacteria can make the lining of the gut become more permeable, allowing toxins to enter the bloodstream where they can travel around the body with various negative effects.

Dysbiosis can have serious health implications including several disorders, such as inflammatory bowel disease, obesity, diabetes, cancer, anxiety and autism, the researchers said.

"Our gut is inhabited by a huge number of bacteria. And there are many different kinds of bacterial species, and the bacterial species that are present can vary a lot from person to person," said lead researcher Floris Fransen from the University Medical Centre Groningen in The Netherlands.

"Since inflammation is thought to contribute to many diseases associated with ageing, and we now find that the gut microbiota plays a role in this process, strategies including changes in diet, probiotics, and prebiotics can alter the gut microbiota composition in the elderly, reducing inflammation and promoting healthy ageing."

For the study, detailed in the journal Frontiers in Immunology, gut bacteria from old mice was transplanted into young mice that induced age-related chronic inflammation.

The team analysed immune responses in the young mices' spleen, lymph nodes and tissues in the small intestine as well as analysed whole-genome gene expression.

The findings may give rise to therapies that target the bacterial composition of the gut in elderly people, through changes to diet and pre- and probiotic supplements, which may lead to a healthier ageing population, the researchers added.