Can an Apple a Day Keep Depression Away?

Maybe the adage is true. Just not the way we thought. A new longitudinal study shows that eating more fruits in midlife can stave off depression later. The research, spearheaded by a team at Yong Loo Lin School of Medicine at the National University of Singapore (NUS Medicine), offers fresh insights into the role one’s diet plays in mental health.

As the world’s population ages, the rate of late-life depression is spreading, too. The condition – marked by the telltale signs of chronic sadness, an absence of pleasure, cognitive delays, and fatigue – is typically linked to neurodegenerative changes in the aging brain.

Earlier research has shown that later-life depression frequently goes hand-in-hand with other comorbidities, from “chronic diseases, functional limitations, arthritis, COPD, pain and sleep problems.”

The social and moral obligation to help keep older adults healthier longer has given rise to a mounting wave of research in preventative measures, such as dietary interventions.

Methodology

The NUS researchers tracked 13,738 participants from the Singapore Chinese Health Study, monitoring their dietary habits and mental health for roughly 20 years. The scientists discovered that participants who consumed higher quantities of fruits in middle age were notably less likely to experience depressive symptoms as they grew older.

The study focused on more than a dozen of most prevalent – and popular – fruits in Singapore, such as apples, bananas, oranges, and papayas. The researchers discovered that the antioxidants and anti-inflammatory micronutrients in these fruits — carotenoids, flavonoids, and vitamin C — might mitigate oxidative stress. These micronutrients can also hinder inflammation, factors that could contribute to depression.

It’s also worth noting that vegetable consumption failed to show a similar benefit.

“Our study underscores the importance of fruit consumption as a preventive measure against aging-related depression,” Professor Koh Woon Puay, the study’s principal investigator, said. “Participants who had at least three servings of fruits a day were able to reduce the likelihood of aging-related depression by at least 21 percent compared to those with less than one serving a day.”

Research 20 Years in the Making

When the researchers launched their study in the mid-1990s, participants, averaging 51 years old at the time, reported their daily consumption of 14 fruits and 25 vegetables through a structured questionnaire.

Almost two decades later, researchers evaluated the study participants for depressive symptoms using the Geriatric Depression Scale. Of the participants, 23.1% reported five or more depressive symptoms.

After adjusting for various confounding factors, including medical history, smoking, physical activity, and sleep duration, the study confirmed that higher fruit consumption in midlife revealed a link to lower odds of late-life depression.

“Our study is one of the largest of its kind in an Asian population,” Koh added. “It suggests that promoting fruit consumption in midlife can yield long-term mental health benefits, extending well into older adulthood.”

These findings boast significant public health implications, highlighting the need for better education and public policy proposals to expand fruit accessibility. Additionally, the researchers plan to explore the impact of other modifiable behaviors, such as sleep duration and smoking, on the mental health of older adults.

The full study appears in the Journal of Nutrition, Health, and Aging.

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