Eating a Mediterranean-style diet could help older people stay healthy as they age, according to scientists who believe it can boost beneficial gut bacteria.
The study involved 612 people aged between 65 to 79 years old from five European countries—the U.K., France, the Netherlands, Italy, and Poland—who either were or were not frail, or were on the cusp of this condition.
The researchers asked them to follow the Mediterranean diet for a year. This regime is made up of high levels of vegetables, legumes, fruits, nuts, olive oil, and fish, and small amounts of red meat, dairy products, and saturated fats, according to the authors of the paper published in the journal Gut.
Switching to the diet usually means people eat more fibers and vitamins, in vegetables and fruits; carbohydrates from wholegrains; plant proteins from legumes, and polyunsaturated fats from fish, which in moderation are thought to improve blood cholesterol levels, according to the AMA. In turn, they become less likely to eat fat, sugar, and salt and drink alcohol.
The team found that sticking to the diet seemed to lower the diversity of the bacteria of the gut microbiome—the term used to describe the population of bugs in our digestive systems—and appeared to help the growth of bacteria previously linked with a lower risk of becoming frail.
The state is characterized by factors including the decline of muscle mass and thinking skills, as well as the development of chronic disease like diabetes and the build-up of plaque in the arteries, and inflammation.
“Our findings support the feasibility of improving the habitual diet to modulate the gut microbiota which in turn has the potential to promote healthier ageing,” the authors wrote, referring to the bacteria which live in our guts.
The study adds to a growing body of evidence suggesting the diet affects the gut microbiome, and improves health overall.
Study co-author professor Paul O’Toole, head of the school of microbiology at the University College Cork, Ireland, told Newsweek: “What we did not know was that consuming this diet changes our internal microbial ecosystem—the gut microbiome—and that is it probably this that makes the diet work. It is not just the food ingredients that are healthy, but how it is converted into beneficial metabolites by the bacterial community it stimulates in the gut.”
He explained: “We had tried previously to improve the microbiome and health of older people in a small cohort in Ireland, by supplementing their diet with 20 grams fibre per day, but the effects were moderate. So we needed to try something more drastic.”
O’Toole said he was surprised that the Mediterranean diet affected participants in all countries, and the same bacteria responded—even though the make-up of the participants’ gut bacteria was different at the start of the project.
However, he acknowledged that the effects on the microbiome were small “but presumably accumulate over time.” O’Toole also highlighted that the team found a slowing down of the rate of frailty over the year the trial was conducted, not a reversal. It is unlikely that would be possible, “though we didn’t try that in this study,” O’Toole said.
O’Toole said everyone should try to follow a Mediterranean diet as closely as possible.
“This can be challenging based on seasonality of food availability, and cost, especially in western and northern Europe. But choosing minimally processed foods is usually feasible to a large extent if you think about it,” he said, urging people to plan their meals to make this easier.
