As populations around the world age rapidly, the prevalence of depressive symptoms among older adults is on the rise. These symptoms, which include feelings of depression, lack of pleasure, delayed cognitive processing, and reduced volitional activity, often come with loss of appetite, insomnia, poor concentration, and increased fatigue. Such mental health challenges are frequently linked to neurodegenerative changes in the brain associated with aging.
The pressing need to maintain the health of older adults has spurred extensive research into preventative approaches for late-life depression. Increasing evidence points to the significant role dietary factors can play in safeguarding mental well-being as we age. A recent longitudinal study from the Yong Loo Lin School of Medicine at the National University of Singapore (NUS Medicine) sheds light on how diet, specifically fruit consumption, can influence mental health in later years.
The study followed 13,738 participants from the Singapore Chinese Health Study, tracking their dietary habits from midlife to later life over approximately 20 years. Researchers found that participants who consumed higher quantities of fruits earlier in life were less likely to experience depressive symptoms in their later years.
The study, published in the Journal of Nutrition, Health and Aging, examined 14 fruits commonly consumed in Singapore, including oranges, tangerines, bananas, papayas, watermelons, apples, and honey melon. The consumption of these fruits was associated with a reduced likelihood of depression. Researchers believe this could be due to the high levels of antioxidants and anti-inflammatory micronutrients in fruits—such as vitamin C, carotenoids, and flavonoids—which help reduce oxidative stress and inhibit inflammatory processes that may contribute to depression. Interestingly, the study found no similar association with vegetable consumption.
Professor Koh Woon Puay, the Principal Investigator of the study and part of the Healthy Longevity Translational Research Programme at NUS Medicine, emphasized the importance of fruit consumption as a preventive measure against aging-related depression. “Our study underscores the importance of fruit consumption as a preventive measure against aging-related depression. In our study population, participants who had at least three servings of fruit a day, compared to those with less than one serving a day, were able to reduce the likelihood of aging-related depression significantly by at least 21%,” she said.
This can be achieved by incorporating one to two servings of fruit after every meal. The study also noted no significant difference between fruits with high and low glycemic indices, meaning that even individuals with diabetes can benefit by choosing fruits with a low glycemic index to avoid spikes in blood sugar levels.
At the beginning of the study, between 1993 and 1998, participants were an average age of 51 years and were asked about their daily consumption of various fruits and vegetables. From 2014 to 2016, when participants were around 73 years old, depressive symptoms were assessed using the Geriatric Depression Scale. Of the participants, 3,180 (23.1%) reported experiencing five or more symptoms indicative of depression.
After adjusting for potential confounding factors such as medical history, smoking status, physical activity, sleep duration, and other aging-related variables, the research team found a clear association: higher fruit consumption was linked to lower odds of depressive symptoms, while vegetable consumption showed no such link.
Professor Koh added, “Our study aimed to examine the relationship of midlife consumption of fruits and vegetables with the risk of depressive symptoms in late life. Although other studies have also examined the associations of fruits and vegetables with risk of depression, there are inconsistencies in the results, and many of them were done in Western populations. To our best knowledge, ours is the largest population-based study in an Asian population to study this association.”
These findings suggest that encouraging fruit consumption during mid-adulthood (ages 40 to 65) could have lasting benefits for mental well-being in late adulthood (beyond 65 years). The study’s results have significant implications for public health education and initiatives aimed at making fruits more accessible to the general population. Following these findings, the research team plans to explore other modifiable behavioral factors, such as sleep duration, smoking, and additional dietary factors, to further understand their impact on the mental health of older adults.
Promoting fruit intake as part of a balanced diet could be a simple yet effective strategy to enhance the mental health of aging populations, potentially reducing the burden of late-life depression and improving overall quality of life for older adults.