The link between diet and physical aging is well-documented. Yet, far less attention is paid to how food affects mental state in later years. A new analysis reveals that these two aspects are far more interconnected than many assumed. Adults over 50 who followed a Mediterranean-style diet reported stronger feelings of well-being. This advantage held steady even during a global pandemic, when overall mood declined across the population.
The study was led by researchers from University College London. They worked alongside partners from the Barcelona Institute for Global Health (ISGlobal). Their findings were published in the journal BMJ Open.
For a long time, the focus was on individual nutrients or specific food items. This study, however, looks at an overall dietary pattern. The Mediterranean diet emphasizes fruits, vegetables, legumes, whole grains, fish, and olive oil while limiting red meat, dairy, and sweets.
Evidence linking the Mediterranean diet to a lower risk of depression is already quite convincing. Large-scale population studies and clinical trials have repeatedly pointed in that direction.
What had been overlooked was the other side of the coin. Earlier attempts to connect diet with happiness mostly considered fruits and vegetables, and little else. The bulk of research on nutrition and mental health has centered on depression. This project posed a different question—one about the positive side of the mind.
Positive psychological well-being goes beyond the mere absence of depression. It encompasses a sense of control, independence, and purpose, as well as reflecting enjoyment of life, energy levels, and optimism about the future.
Data came from the English Longitudinal Study of Aging (ELSA), a long-term survey of England’s population. The sample included 3,296 adults aged 50 to 90. Participants recorded everything they ate and drank over two separate days in 2018 and 2019.
Each participant’s diet was then scored based on how closely it matched the Mediterranean diet. This score considered nine food groups, from olive oil to fish and red meat. The higher the total, the better the adherence, with a range from zero to 14 in this group.
Well-being was measured using a questionnaire designed for older adults. It asked about life’s meaning, enjoyment of life, and the feeling that life still holds promise. Higher diet-related scores correlated with higher well-being scores. This pattern held up across numerous checks.
Factors like income, education, physical activity, smoking, and overall health were taken into account, yet the link remained. The connection also persisted after adjusting for total calorie intake, which rules out simple malnutrition as the cause.
One obvious concern is that a low mood might negatively affect both diet and overall disposition. The research team tested just that. Even after accounting for depression symptoms, the connection barely changed. The Mediterranean diet appears to influence well-being on its own, not just by easing stress.
A single snapshot isn’t enough to determine what comes first: diet or a positive outlook. A cheerful person might simply choose healthier food, rather than the other way around. The COVID-19 outbreak gave the team a rare opportunity for a natural experiment. Diet was measured long before the crisis, so it couldn’t have been altered by the stress that followed.
As lockdowns and fear intensified, well-being declined across the entire group. But among those who had followed a Mediterranean diet years earlier, the drop was less pronounced. This buffer remained even after accounting for who had caught the virus. It also stayed strong when depression symptoms were added to the mix.
“Our study is observational, so the results should be interpreted with caution, as we cannot draw causal conclusions,” said lead author Camille Lassale. “Nevertheless, the questionnaire conducted during the pandemic allowed us to track participants over a long period, which is one of the study’s main strengths.”
Lassale noted that researchers are still exploring how the Mediterranean diet affects mental health. However, existing evidence suggests that foods commonly included in this diet may help regulate stress responses, reduce inflammation, support gut health, and enhance brain function.
The exact chemical makeup is still being refined. Certain ingredients consistently pop up in this area of research. Fiber, omega-3 fatty acids, and plant polyphenols rank high on the list. Reducing intake of processed meat and sugar may also play a role.
“This study provides additional evidence of the link between what we eat and our mental health—a new area of research that we hope will yield significant new insights in the coming years,” said co-author Alanna Shand.
Research on diet and mood is a relatively new but fast-growing field. Each group of investigators like this contributes to the emerging picture.
Those who filled out the dietary questionnaire weren’t a perfect sample. They tended to be more educated, wealthier, and healthier than those who skipped it. The group was predominantly white, so the findings may not apply to everyone. Diet was assessed over just two days, and well-being was recorded only once during the pandemic.
“While many questions remain open, there is no doubt about the need to promote healthy lifestyles, especially balanced diets rich in plant-based foods and low in items like processed meat and sweets, particularly among older adults,” said co-author Andrew Steptoe from University College London.
The main takeaway is simple and achievable. No perfect diet is required—just a gradual increase in plant foods, fish, and healthy fats. For an aging population, this small shift could yield a double benefit. It may protect the body from aging while simultaneously strengthening the mind.
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