The Mediterranean diet is regarded as the classic eating habits of populations from countries such as France, Greece, Spain and Italy.
It has been thought to improve heart health and stave off cancer.
But a new US study shows further benefits to the brain where it is linked to lower levels of white matter hyperintesity volume, a marker of damage to the small vessels, the Daily Mail reported.
Some researchers believe the diet keeps the grey cells healthy by cutting inflammation, while others say the high intake of antioxidant vitamins may also protect the brain.
The new study examined for the first time the relationship between the Mediterranean diet and lesions in the brain, known as white matter hyperintensities (WHM).
Study leader Hannah Gardener of the University of Miami Miller School of Medicine, and colleagues looked at data on almost 1,000 people with an average age of 72 years taking part in the Northern Manhattan Study.
Participants were given a food frequency questionnaire to assess dietary patterns during the previous year, and answers were used to determine a score from 0-9 indicating how much they stuck to a Mediterranean diet, with a higher MeDi score showing greater compliance.
The volume of chronic age-related white matter damage was measured using brain MRI scans.
Results of the survey showed that 11.6 per cent of participants scored 0 to 2 on the MeDi scale, 15.8 per cent scored 3, 23 per cent scored 4, 23.5 per cent scored 5, and 26.1 per cent scored 6 to 9.
Women had lower scores than men and those engaged in moderate to heavy levels of physical activity had higher scores.
Those scoring 6 or higher also had lower Body Mass Index scores, suggesting healthier weights.
The results show a lower burden of WMHV among people sticking to a Mediterranean diet, even after allowing for risk factors including physical activity, smoking, blood lipid levels, hypertension, diabetes, history of cardiac disease and BMI.
The only component of the MeDi score showing independent benefit with less brain damage was higher consumption of monounsaturated fat such as olive oil compared with saturated fat, including butter.
"Although diet may be an important predictor of vascular disease, little is known about the possible association between dietary habits and WMH," said Dr Gardener.
"Studies have suggested that consumption of a Mediterranean Diet is associated with a reduced risk of the metabolic syndrome, coronary heart disease, stroke and cognitive disorders, but no studies to date, to our knowledge, have examined the association with WMH volume.
"In summary, the current study suggests a possible protective association between increased consumption of a MeDi and small vessel damage," she stated.
The results suggest the overall dietary pattern, rather than any of the individual components, was the most important factor, according to the study.
The study appeared in the Archives of Neurology medical journal.