Study shows adherence to Mediterranean diet is associated with successful aging

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

Global trends in population aging are believed to affect the incidence of age-related noncommunicable diseases. According to the latest Global Burden of Disease report, approximately 55 million people are affected by dementia. Additionally, depression and anxiety disorders are widespread, with around 300 million and 260 million people affected respectively.

Evidence suggests that depression and sleep disturbances may represent the prodrome of early onset cognitive deficits. Collectively, cognitive and mental disorders represent a global public health problem due to their impact on aging and the quality of life of older adults.

Several studies have shown that healthy eating habits with natural plant-based products, such as the Mediterranean diet, can improve mental/cognitive health in older adults. However, fewer studies have been conducted among people living in/around the Mediterranean, where adherence to the Mediterranean diet is still preserved.

Study: Mediterranean Diet, Mental Health, Cognitive Status, Quality of Life, and Successful Aging in Southern Italian Elderly. Image Credit: leonori/Shutterstock

About the study

The present study investigated the associations between adherence to the Mediterranean diet and mental/cognitive health, quality of life, and ‘successful aging’ among older adults in Sicily, Italy. People aged 18 or over in the districts of Catania were recruited in 2014-2015 to create an observation cohort for the Mediterranean Study on Healthy Eating, Aging and Lifestyle (MEAL).

Personal interviews were conducted and data on age, sex, education, occupation, smoking status and physical activity were collected. Both the long and short versions of the Food Frequency Questionnaires (FFQs) were used to assess food intake. Energy and macro/micronutrient intake was determined by comparison with food composition tables.

Polyphenol intake was estimated using the Phenol-Explorer database. Adherence to the Mediterranean diet 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 in Depression (CES-D) short form.

The Short Portable Mental Status Questionnaire (SPMSQ) and the Manchester Short Assessment of Quality of Life (MANSA) were used for assessments of cognitive health and quality of life, respectively. The Successful Aging Index (SAI) was used to assess successful aging. The team ranked the sample into quartiles of Mediterranean diet adherence scores.

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

Results

Overall, 883 seniors were included in the analysis. Most of the participants were married and had never smoked. The people most faithful to the Mediterranean diet had average physical activity; moreover, participants with the lowest adherence were more likely to skip breakfasts. Individuals in the highest compliance quartile had a significantly higher intake of carbohydrates, protein, fiber, vitamins A, C and E, potassium and sodium.

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

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

When the diet adherence score was considered as 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 diet adherence quartile were more likely to age successfully. A one-point increase in compliance score was associated with a 10% higher probability of successful aging.

conclusion

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

Additionally, a significant nonlinear association was observed for sleep quality. Together, the results suggest that adherence to the Mediterranean diet may provide a positive trajectory to successful aging, with potential mental/cognitive health benefits.