Study shows adherence to Mediterranean diet associated with successful aging

By Tarun Sai LomteReviewed by Danielle Ellis, B.Sc.Mar 21 2023

A recent study published in the journal Experimental Gerontology examined the relationship between adherence to the Mediterranean diet and age-related health outcomes in older adults in Sicily, Italy.

The global trends in the aging population are estimated to affect the incidence of age-related non-communicable diseases. According to the latest report on the global disease burden, around 55 million individuals are affected by dementia. Moreover, depression and anxiety disorders are highly prevalent, with about 300 million and 260 million people affected, respectively.

Evidence suggests that depression and sleep disorders may represent the prodroma of early-onset cognitive deficits. Collectively, cognitive and mental disorders represent a global public health concern due to their impact on aging and quality of life in the elderly population.

Several studies have demonstrated that healthy dietary patterns with plant-based natural products, such as the Mediterranean diet, may improve mental/cognitive health among older people. However, fewer studies have been conducted among people living in/around the Mediterranean, where Mediterranean diet adherence is still preserved.

Study: Mediterranean diet, mental health, cognitive status, quality of life, and successful aging in southern Italian older adults. Image Credit: leonori / Shutterstock

About the study

The present study investigated the associations between Mediterranean diet adherence and mental/cognitive health, quality of life, and “successful aging” in older adults in Sicily, Italy. People aged 18 or older in the districts of Catania were enrolled during 2014-15 to create an observational cohort for the Mediterranean healthy eating, aging, and lifestyle (MEAL) study.

Personal interviews were conducted, and data on age, sex, education, occupation, smoking status, and physical activity were collected. The long and short versions of food frequency questionnaires (FFQs) were used to assess dietary intake. Intake of energy and macro/micro-nutrients was determined by comparing with food composition tables.

Polyphenol intake was estimated using the Phenol-Explorer database. Mediterranean diet adherence was scored and stratified into low, medium, and high adherence categories. The Pittsburgh sleep quality index (PSQI) was used to assess sleep quality. Depression was assessed using the Center for Epidemiological Studies of Depression Short Form (CES-D).

The Short Portable Mental Status Questionnaire (SPMSQ) and Manchester Short Assessment of Quality of Life (MANSA) were used for cognitive health and quality of life evaluations, respectively. The successful aging index (SAI) was used for assessing successful aging. The team categorized the sample into quartiles of Mediterranean diet adherence scores.

Logistic regression was used to compute odds ratios and 95% confidence intervals for associations between diet adherence and outcomes. The associations with sleep quality, quality of life, depressive symptoms, and cognitive status were evaluated using multivariate logistic regression models. An age- and sex-adjusted model predicted the association between diet adherence and SAI.

Findings

Overall, 883 older adults were included in the analysis. Most participants were married and never smokers. Individuals with the highest adherence to the Mediterranean diet had medium physical activity; additionally, participants with the lowest adherence were likelier to skip breakfasts. Individuals in the highest quartile of adherence had a significantly higher intake of carbohydrates, protein, fiber, vitamins A, C, and E, potassium, and sodium.

They also consumed more vegetables, cereals, and fruits but less meat. Polyphenol intake was also higher among participants in the highest quartile of adherence. Significant differences were observed for CES-D, SPSMQ, and MANSA scores according to quartiles of adherence. PSQI scores were not significantly different.

Individuals in the highest quartile (of Mediterranean diet adherence) were likelier to have a good quality of life and less likely to have depressive symptoms and cognitive impairment after adjusting for potential confounders. Moreover, individuals in the third quartile were also likely to have good sleep quality.

When the diet adherence score was deemed a continuous variable, a one-point increase was associated with an 11% decrease in cognitive impairment and a 51% increase in quality of life. Participants in the highest quartile of diet adherence were likelier to have successful aging. A one-point rise in adherence score was associated with 10% higher odds of successful aging.

Conclusions

The study explored the relationship between Mediterranean diet adherence and outcomes focused on cognitive and mental health and quality of life in older adults. The findings revealed a consistent association of higher Mediterranean diet adherence with better cognition, quality of life, and lower depressive symptoms than those with less adherence.

Additionally, a significant non-linear association was observed for sleep quality. Together, the findings suggest that Mediterranean diet adherence can provide a positive trajectory towards successful aging, with potential mental/cognitive health benefits.