Eating more fruits, vegetables, beans, whole grains, fish and olive oil may do more than protect the heart—it could also help older adults maintain a stronger sense of purpose, independence and emotional resilience, according to a new study by researchers at University College London (UCL) and the Barcelona Institute for Global Health (ISGlobal), published in BMJ Open.

The researchers tracked 3,296 adults aged between 50 and 90 years participating in the English Longitudinal Study of Ageing (ELSA) and found that people who closely followed a Mediterranean diet consistently reported higher levels of psychological well-being over time. Unlike many earlier studies that focused mainly on depression, this research examined the positive side of mental health—whether people felt in control of their lives, enjoyed daily living, remained independent and believed their lives had meaning.

Perhaps the most striking finding emerged during the COVID-19 pandemic. While lockdowns and prolonged isolation caused emotional well-being to fall across the study population, those who had stayed closest to a Mediterranean-style eating pattern experienced a noticeably smaller decline. The findings suggest that healthy eating may act as a buffer against severe psychological stress, even during major global disruptions.

The researchers stress that this was an observational study, meaning it identifies a strong link rather than proving that diet alone caused the improvements. Even so, the association remained significant after accounting for income, education, social background and previous depressive symptoms, indicating that the benefits were not simply explained by wealth or better overall health.

"Our study is observational, and, therefore, the results should be interpreted with caution since we cannot draw causal conclusions," said Camille Lassale, ISGlobal researcher and senior author of the study.

"Nevertheless, the questionnaires administered during the pandemic allowed us to follow participants over time, which is a major strength of the study. Although researchers are still looking into how the Mediterranean diet improves mental health, there is evidence that its main foods and ingredients help manage important functions like stress, inflammation, gut health, and brain activity, she added.

Scientists believe foods commonly found in the Mediterranean diet contain natural compounds that reduce harmful inflammation, support healthy gut bacteria, help regulate stress hormones and protect communication between brain cells. Growing evidence from studies published in journals including The Lancet, Nature Medicine and JAMA Network Open has also linked healthier diets with better brain health and lower risks of depression and cognitive decline.

"This study provides further evidence of the relationship between what we eat and our mental health, an emerging field of research that we hope will generate substantial new evidence in the years to come," said research psychologist and co-author Alanna Shand.

"Although many questions remain open, there is no doubt about the need to promote healthy lifestyles, prioritising a balanced diet rich in plant-based foods and low in foods such as processed meats and sweets, particularly among older adults," said Andrew Steptoe, researcher at UCL and first author of the study.

The findings strengthen the growing case that healthy eating should be viewed not only as a tool to prevent disease but also as a practical way to help older people remain mentally resilient, independent and engaged as populations continue to age.