Mediterranean diet

(Credit: Ponyo Sakana from Pexels)

LONDON — For decades, the health benefits of the Mediterranean diet have been touted by many healthy eaters. In January, media outlets named the diet the best in the world for the third year in a row. So why is the diet so good for us? A study is adding that gut microbiome — the bacteria living in the human gastrointestinal tract — to the list of reasons.

Researchers from eight European countries determined whether the best diet in the world could promote gut bacteria linked to “healthy aging” in a group of older adults. The group followed a traditional Mediterranean diet, high in fruits, vegetables, nuts, legumes, healthy fats like olive oil, and fish. Bacteria previously found in elderly with better physical and brain function increased. Bacteria that decreases inflammation also increased.

The authors caution that some older people might have trouble chewing or swallowing specific foods in this diet. They suggest an easy-to-swallow probiotic or dietary supplement, containing the beneficial bacteria in these foods, can better deliver these nutrients.

Mediterranean diet feeds our microbes, gut health

To determine whether a Mediterranean diet could promote a healthy gut microbiome in older adults, researchers had 612 Europeans between 65 and 79 years-old in five different countries switch to the diet. The team analyzed each person’s microbiome both before starting the diet and again one year later. They also measured frailty and brain function.

Although each person’s microbiome had unique qualities at the start of the study, each participants experienced similar changes. Additionally, the beneficial effects didn’t depend on the person’s age, weight, or nationality.

Not only did the researchers find several bacteria with a connection to less frailty and better brain function, but they also identified a decrease in bacteria that have a link to bowel cancer, insulin resistance, and fatty liver. They concluded that the fiber, iron, copper, potassium, manganese, magnesium, and B-vitamins from the diet helped the good bacteria flourish.

Study authors cautioned that these results don’t imply a cause-effect relationship, however.

“The interplay of diet, microbiome and host health is a complex phenomenon influenced by several factors,” the team writes in a media release. “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.”

These findings are published in the BMJ Journal Gut.

About Embriette Hyde

Our Editorial Process

StudyFinds publishes digestible, agenda-free, transparent research summaries that are intended to inform the reader as well as stir civil, educated debate. We do not agree nor disagree with any of the studies we post, rather, we encourage our readers to debate the veracity of the findings themselves. All articles published on StudyFinds are vetted by our editors prior to publication and include links back to the source or corresponding journal article, if possible.

Our Editorial Team

Steve Fink


Chris Melore


Sophia Naughton

Associate Editor