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Study links diet, gut bacteria and health status

7 September 2012

Julian Marchesi

Dr Julian Marchesi

A Cardiff research team has contributed to a study which shows that a relationship exists between diet, gut bacteria and the health of older Irish people.

Dr Julian Marchesi’s research group was part of a multidisciplinary team of scientists from University College Cork (UCC), Teagasc Food Research Centre (Moorepark, Fermoy) and Cardiff University whose work has recently been published in the journal Nature. Their findings, which show that diet can influence the composition of gut bacteria and in turn influence a person’s health, offer exciting new opportunities for the food industry, providing the scientific basis for developing foods to promote healthier ageing.

It is well known that gut microbiota - the community of bacteria in the gut - is required for immune development in infants and maintenance of health in adult life, and changes in the composition of our microbiota have been linked to inflammatory and metabolic disorders such as Inflammatory Bowel Disease, Irritable Bowel Syndrome, and obesity.

As we age, we may experience deterioration in our immune system, dental health, salivary function and digestion, and this can also affect the good bacteria that live in our gut. Some of these changes are out of our control, but we can control our diet. However, until now, links between diet, gut microbiota composition and health in large human studies were unclear.

The team collected information on diet, physical activity, immune function, and cognitive function, while Dr Marchesi measured the faecal microbiota composition of 178 older persons living in different settings in the South of Ireland.  

The study, funded by the Irish Health Research Board and the Department of Agriculture Food and the Marine, found that the healthiest people, living in a community setting, eat differently and have a distinct microbiota compared to those in long-term residential care. It can be inferred from findings related to increased inflammation and increased frailty, that there is a diet-microbiota link to these indicators of accelerated ageing. 

Dr Marchesi, who helped design the experimental work, asserts that “it is evident that diet and particular food ingredients are able to promote certain components of the gut microbiota, which may be useful for maintaining health in older individuals.  The next stage of the work is to combine profiling of the gut microbiota with measurements of metabolites (metabonomics) to determine biomarkers which identify individuals at risk of less healthy ageing”.