The so-called Mediterranean diet—which focuses mainly on fresh vegetables, fish, whole grains, and olive oil—has received a lot of press in recent years for its heart-health benefits. Studies have shown that people who follow this basic eating plan have a reduced risk of both cardiovascular disease and all-cause mortality. A large study of women, for example, found that those who followed this basic eating plan for 12 years had 25 percent less risk of developing heart disease, and a large meta-analysis found that women with the highest adherence to the diet had a 23 percent lower risk of premature death.
The Mediterranean diet’s benefits may not be limited to the heart, however, as other studies have shown that it can reduce insulin resistance, ease symptoms of Parkinson’s disease, and may even reduce the risk of certain types of cancers.
Now, a team of European researchers has added to the evidence of the diet’s health benefits with a study showing that it may help prevent cognitive decline in older adults. Their study was published in the journal Molecular Nutrition & Food Research.
Part of the Joint Programming Initiative “A Healthy Diet for a Healthy Life,” the 12-year study followed 840 people over 65 years of age who lived in the Bourdeaux and Dijon regions of France. The researchers used baseline serum levels of saturated and unsaturated fatty acids, gut microbiota-derived polyphenol metabolites, and other phytochemicals as biomarkers for exposure to the main food groups in the Mediterranean diet. Many of these indicators have not only been previously identified as markers for exposure to the diet but have also been posited as responsible for its health benefits.
Serum levels of these biomarkers were studied in participants without dementia at the beginning of the study. Cognitive impairment was then assessed by five neuropsychological tests performed over a period of twelve years. After final analysis, the results of the study revealed a protective association between the score of the Mediterranean diet based on serum biomarkers and cognitive decline in older people.
“We found that adherence to a Mediterranean diet assessed by a panel of dietary biomarkers is inversely associated with long-term cognitive decline in older people,” said first author Alba Tor-Roca of the University of Barcelona.
Unlike many dietary studies, this one didn’t rely on self-reported adherence to an eating plan, which gives it several advantages. “The use of dietary pattern indices based on food-intake biomarkers is a step forward towards the use of more accurate and objective dietary assessment methodologies that take into account important factors such as bioavailability,” said Mercè Pallàs, PhD, another of the study’s authors.
The study did suffer from several drawbacks, however, not least of which was the fact that serum samples for analysis were only available at baseline, so researchers could not determine whether dietary changes over the 12-year study period influenced the outcome.
Despite its limitations, however, the study has opened up avenues for further investigation into the Mediterranean diet’s potential benefits for preventing dementia. “These results support the use of these indicators in long-term follow-up assessments to observe the health benefits associated with the Mediterranean diet or other dietary patterns and therefore, guide personalized counseling at older ages,” Tor-Roca said.