A new study shows how gut bacteria can name the benefits of the ‘Mediterranean diet’.
The Mediterranean diet is a broad and loose term that usually refers to to the food eaten in Greece, southern Italy and parts of Spain. Unfortunately, this does not mean that you should eat a pepperoni pizza and a bottle of wine every night, but refer to a rich diet in vegetables, fruits, legumes, nuts, beans, grains, cereals, fish and unsaturated fats, such as olive oil. Eating these types of foods regularly is associated with all sorts of positive health effects, especially for the heart and the cardiovascular system.
In a new study, published in the journal this week Physical Medicine, scientists claim that some of the health benefits of the Mediterranean diet may actually lie in the way the diet interacts with our gut microbiome.
The trillions of bacteria, viruses, protozoa and fungi that live in the human intestinal tract are much more than passive sleeping places. They are also known to play a central role in our body’s metabolism, nutrition and immune function, which can affect our overall health and even our mood.
Researchers at the Harvard TH Chan School of Public Health looked at the health and gut microbiome of more than 300 healthy men. Along with taking poop samples for two years every six months, they were also asked to complete a questionnaire about their diet. They found that those who followed a Mediterranean diet had a striking composition of intestinal bacteria, namely high concentrations of the major metabolizers of dietary fiber, Faecalibacterium prausnitzii and Bacteroides cellulosilyticus.
Furthermore, the presence of one bacterial species, known as Prevotella copri, was found to have a particularly interesting link with cardiovascular health. The researchers found that people with reduced levels of P. copri apparently experienced more of the positive effects of the Mediterranean diet on cardiometabolic diseases. In other words, people with little or no P. copri get more out of the benefits of the Mediterranean diet.
The researchers are not sure why P. copri apparently have this link but they have some ideas. First, it may be simple that unhealthy diets, which increase the risk of cardiovascular risks, tend to increase the P. copri. Alternatively, individuals who do not wear P. copri in the gut, microbiome can metabolize ingredients of the Mediterranean diet more efficiently and effectively, thus obtaining more of the cardioprotective effects.
However, the exact nature of this relationship remains speculation for the time being. The researchers point out that their study was merely observational and that they were limited in their ability to understand the underlying mechanism behind the patterns they observed. They also note that the interaction between the microbiome and the diet is a very troublesome matter. Many different subclasses of P. copri can be found in different populations around the world, probably due to dietary and lifestyle differences, and not all clades can interact with the Mediterranean diet as seen here.
That said, this research is a great example of how new research sheds light on the mechanisms underlying the relationship between the microorganisms that live in us and diseases.