EATING A MEDITERRANEAN diet can boost gut bacteria linked to healthy ageing, according to a new study by researchers in University College Cork. 

The study, published today, found that a Mediterranean diet also lowers the risk of harmful inflammation in older people. 

A so-called Mediterranean diet is one rich in fruits and vegetables, nuts, olive oil and fish – and low in red meat and saturated fats. 

The researchers found that a Mediterranean diet acts on gut bacteria in a way that helps to limit the advance of physical frailty and cognitive decline in old age. 

The work was building on previous studies that suggest that a poor and restrictive diet, common among older people, reduces the types of bacteria found in the gut – potentially worsening the ageing process. 

The study analysed the gut bacteria of 612 people aged between 65 and 79, before and after either eating their normal diet or a Mediterranean diet. 

Participants – who were from France, Italy, Netherlands, Poland and the UK -were categorised in three different ways – “frail”, “on the verge of fraility” and “not frail”. 

Impact

Prof Paul O’Toole, who works in APC Microbiome Ireland – a Science Foundation Ireland-funded centre – led the research in University College Cork. 

At the end of 12 months, people on the Mediterranean diet were found to have better walking speed and hand grip strength, as well as improved brain function, such as memory. 

The study’s findings can’t fully establish a causative link between the role of gut bacteria in health.

“The interplay of diet, microbiome and host health is a complex phenomenon influenced by several factors,” the researchers write.

“While the results of this study shed light on some of the rules of this three-way interplay, several factors such as age, body mass index, disease status and initial dietary patterns may play a key role in determining the extent of success of these interactions,” the researchers explain. 

However, a detailed analysis found that the microbiome changes were associated with a decrease in bacteria involved in producing a particular type of bile acid linked to heightened risk of bowel cancer and insulin resistance. 

The changes were also largely caused by an increase in dietary fibre and associated vitamins and minerals, including copper, potassium, iron and magnesium. 

While the study acknowledges that diet and ageing is a complex area, the researchers suggest that beneficial bacteria may have something important to contribute to healthy ageing.