Early fruit consumption may ward off late-life blues

Increased fruit consumption among middle-aged men and women has been linked to reduced likelihood of depressive symptoms in old age in a large Singapore study.

Data from 13,738 adults (58.2 percent women) from the Singapore Chinese Health Study showed a dose-dependent association between high fruit and vegetable intake in midlife (mean age 52.4 years) and lower odds of depressive symptoms in later life (mean age 72.5 years; fourth vs first quartile: odds ratio [OR], 0.70, 95 percent confidence interval [CI], 0.62−0.80; p<0.01). [J Nutr Health Aging 2024;28:100275]

However, when fruits and vegetables were analysed separately, adjusting for each other’s effect, the protective effect on depressive symptoms was found to be specific to fruit. The fourth quartile of fruit intake was associated with 29-percent lower odds of having depressive symptoms in old age compared with the first quartile (OR, 0.71, 95 percent CI, 0.63−0.81; p<0.01). There was a linear 14-percent decrease in the odds of having late-life depressive symptoms for each standard deviation-increase in fruit consumption (OR, 0.86, 95 percent CI, 0.82−0.91; p<0.01).

Moreover, significant associations were observed for several types of fruits, including orange (OR, 0.80, 95 percent CI, 0.71–0.91), tangerine (OR, 0.82, 95 percent CI, 0.69–0.98), banana (OR, 0.76, 95 percent CI, 0.64–0.90), papaya (OR, 0.80, 95 percent CI, 0.66–0.97), and watermelon (OR, 0.73, 95 percent CI, 0.56–0.96). The same was true across subgroups of fruits categorized by glycaemic index (low-glycaemic index: OR_Q4vsQ1, 0.81, 95 percent CI, 0.72–0.92; moderate-glycaemic index: OR_Q4vsQ1, 0.81, 95 percent CI, 0.71–0.92; high-glycaemic index: OR_Q4vsQ1, 0.82, 95 percent CI, 0.72–0.93).

In contrast, intake of vegetables across different subgroups showed no significant association with depressive symptoms.

“Our study underscores the importance of fruit consumption as a preventive measure against ageing-related depression,” said principal investigator Prof Woon Puay Koh from the Healthy Longevity Translational Research Programme at NUS Medicine in Singapore.

“In our study population, participants who had at least 3 servings of fruits a day, compared with those with less than 1 serving a day, were able to reduce the likelihood of ageing-related depression significantly by at least 21 percent. This can be achieved by eating one to two servings of fruits after every meal,” Koh added.

What’s more, she said, is that individuals with diabetes can select fruits with lower glycaemic values to benefit from their potential mood-boosting benefits without compromising the potential benefits for mental health.

According to Koh, fruits may offer protection against depression due to being rich in antioxidants and anti-inflammatory compounds, such as vitamin C, carotenoids, and flavonoids. These nutrients are known to combat oxidative stress and inflammation, both of which have been linked to the development of depressive symptoms. [Arch Gen Psychiatry 2009;66:1090-1098; Transl Psychiatry 2016;6:e743; Am J Geriatr Psychiatry 2020;28:87-98]

While vegetables are also rich sources of the aforementioned compounds, fruits are often consumed raw, preserving the potency of these nutrients, Koh explained. In contrast, vegetables are cooked for meals, and cooking can potentially reduce the bioavailability of the beneficial compounds and limit their protective effects on depression, she continued. [Food Chem 2004;88:503-509]

“However, these are just our postulations, and further studies are needed to identify the specific micronutrients present abundantly in fruits that may mediate the protective effects of fruits on depression,” Koh said.

For the study, consumption levels of 14 fruits and 25 vegetables at baseline, when participants were between 45 and 74 years of age, were assessed using a validated 165-item food-frequency questionnaire. Then, depressive symptoms were evaluated using the Geriatric Depression Scale during the third follow-up interviews, when participants were between 61 and 96 years of age.

Median consumption of fruits and vegetables at baseline was 192.1 g/day and 103.9 g/day, respectively. Participants in the highest vs lowest intake quartile of fruits and vegetables tended to be younger, women, educated, and have higher BMI, were less likely to be current smokers and daily drinkers, and were more likely to be physically active and to get the recommended amount of sleep. A total of 3,180 participants (23.1 percent) participants were identified to have depressive symptoms after 19.6 years of follow-up.