The role of diet in influencing the gut microbiome composition is widely recognized along with the outstanding effects of gut microbial activities on human health. The Mediterranean diet (MD) is recognized by UNESCO as an intangible cultural heritage. It is a nutritionally recommended dietary pattern characterized by high-level intake of fruit, vegetables, legumes, nuts, minimally processed cereals, moderately high consumption of fish, low intake of saturated fat, meat and dairy products, regular but moderate consumption of red wine and extra virgin olive oil as the main fat. MD can be beneficial for both prevention and treatment of several diseases such as obesity, type II diabetes, inflammatory diseases, colorectal cancer and cardiovascular diseases.
This new research collaboration with the team of Prof. Danilo Ercolini and Paola Vitaglione from the University of Naples Federico II (Italy) and the team of Prof. Lars Dragsted and Henrik Roager from the University of Copenhagen (Denmark) has highlighted the beneficial effects of a Mediterranean diet in overweight and obese individuals after only 4 weeks of nutritional intervention.
Switching to a MD increases gene richness in individuals with reduced inflammation accompanied by a rise in the fibre-degrading Faecalibacterium prausnitzii and a decrease of potentially proinflammatory species such as Ruminococcus gnavus.
Microbial metabolites of importance for human health were also measured. Increase in the levels of the anti-inflammatory urolithins was observed. Such compounds derive from gut microbial metabolism of ellagitannins, belonging to the family of polyphenols that are abundant in the nuts, which were daily consumed by the subjects during the nutritional intervention. Consistent links were highlighted between production of urolithins and their microbial producers in the gut (Eggerthellaceae).
A MD-tailored dietary intervention can be also helpful in getting clinical advantages such as ameliorating insulin sensitivity in individuals harboring lower baseline levels of Prevotella copri.
The findings are in line with the concept of personalized responses to dietary interventions and are relevant for clinical practice in the era of precision medicine and individualized nutrition, the researchers point out.