- The study followed 746 older adults over a six‑year period, all of whom were at high risk of cardiovascular and metabolic diseases such as diabetes
- The results identify a ‘microbial footprint’ linked to this dietary pattern that could help preserve cognitive function during ageing
Alicante, 29.01.2026.— Researchers from the Nutrition Epidemiology (EPINUT) group at the Alicante Institute for Health and Biomedical Research (ISABIAL) and the Miguel Hernández University of Elche (UMH), within the framework of the PREDIMED‑PLUS Study, have linked adherence to the Mediterranean diet with a healthier gut microbiota and slower cognitive decline in older adults with overweight or obesity and metabolic syndrome.
The study, published in BMC Medicine, was led by researchers from the Universitat Rovira i Virgili and involved the participation of the EPINUT group at UMH, linked to the Alicante Institute for Health and Biomedical Research (ISABIAL) and to the Carlos III Health Institute (ISCIII) through the CIBERESP network.
As Jesús Vioque, lead author of the study and head of ISABIAL’s EPINUT group, explains, “following a Mediterranean dietary pattern benefits the heart and metabolism, and in recent years we are increasingly finding evidence that it may also help preserve cognitive function as ageing progresses”.
Cognitive function encompasses abilities such as memory, attention, learning, language and decision‑making, all of which are essential for maintaining autonomy in daily life. As the years go by, these functions may progressively deteriorate and, in some cases, this process accelerates and can lead to more serious problems, such as dementia.
“Understanding which lifestyle factors may help slow this decline is one of the major current questions in healthy ageing research”, notes Vioque. In this context, the team set out to analyse whether the Mediterranean diet leaves a recognisable imprint on the gut microbiota and whether this microbial health is, in turn, associated with a more favourable cognitive trajectory.
To this end, the study followed 746 men and women over a six‑year period, with an average age of 65 and a high risk of cardiovascular and metabolic diseases such as diabetes. All participants were part of the PREDIMED‑PLUS Study, one of the largest nutritional intervention cohorts developed in Spain.
The results show that individuals with greater adherence to the Mediterranean diet had a more favourable gut microbiota and a more positive cognitive trajectory over time.
One of the most innovative aspects of the study is the identification of a ‘microbial fingerprint’ characteristic of the Mediterranean diet. “Combining dietary habit data with the analysis of the gut microbiota has allowed us to identify a new way of monitoring health”, explains UMH researcher Laura Torres, who is also an author of the study.
This biomarker is based on the presence and abundance of specific gut bacteria associated with the Mediterranean diet. Biomarkers, or biological markers, are measurable signals that make it possible to identify physiological or pathological processes, detect diseases at an early stage, monitor their progression, or assess the effectiveness of therapeutic or preventive interventions.
According to the authors, this microbial signature is associated with slower cognitive decline, providing new insights into the biological mechanisms that explain the benefits of the Mediterranean diet for brain health.
“The gut microbiota is made up of trillions of bacteria that take part in key processes such as digestion, immunity and the production of substances that influence how the body functions”, explains Torres, who adds that recent research has highlighted the existence of the so‑called ‘gut–brain axis’, a bidirectional communication system through which intestinal microorganisms can produce compounds that reach the brain and affect its functioning.
As the authors point out, these results—together with those obtained in previous studies by the same group published in journals such as MedComm and Microbiome—could contribute in the future to the design of nutritional or microbial interventions aimed at promoting healthy cognitive ageing through diet.
The study was funded by the Carlos III Health Institute through the CIBER for the Physiopathology of Obesity and Nutrition (CIBEROBN), as well as by the PREDIMED‑PLUS Study with European co‑funding, and supported by various national and international programmes in nutrition research and healthy ageing.