Summary: People who regularly snack on fruit are less likely to report symptoms of depression and more likely to report positive well-being. Those who indulge in nutrient-poor snacks, such as chips, are more likely to report symptoms of anxiety.
Source: Aston University
People who frequently eat fruit are more likely to report greater positive mental well-being and are less likely to report symptoms of depression than those who do not, according to new research from the College of Health and Life Sciences, Aston University.
The researchers’ findings suggest that how often we eat fruit is more important to our psychological health than the total amount we consume during a typical week.
The team also found that people who eat savory snacks such as crisps, which are low in nutrients, are more likely to report greater levels of anxiety.
Published in the British Journal of Nutrition, the study surveyed 428 adults from across the UK and looked at the relationship between their consumption of fruit, vegetables, sweet and savory food snacks, and their psychological health.
After taking demographic and lifestyle factors such as age, general health and exercise into account, the research found that both nutrient-rich fruit and nutrient-poor savory snacks appeared to be linked to psychological health. They also found that there was no direct association between eating vegetables and psychological health.
Based on the survey, the more often people ate fruit, the lower they scored for depression and the higher for mental well-being, independent of the overall quantity of fruit intake.
People who frequently snacked on nutrient-poor savory foods (such as crisps) were more likely to experience “everyday mental lapses” (known as subjective cognitive failures) and report lower mental well-being. A greater number of lapses, was associated with higher reported symptoms of anxiety, stress and depression, and lower mental well-being scores.
By contrast, there was no link between these everyday memory lapses and fruit and vegetable intake or sweet snacks, suggesting a unique relationship between these nutrient-poor savory snacks, everyday mental lapses, and psychological health.
Examples of these frustrating little everyday mental lapses included forgetting where items had been placed, forgetting the purpose of going into certain rooms, and being unable to retrieve names of acquaintances whose name was on the “tip of the tongue.”
Lead author, Ph.D. student Nicola-Jayne Tuck commented that “very little is known about how diet may affect mental health and well-being, and while we did not directly examine causality here, our findings could suggest that frequently snacking on nutrient-poor savory foods may increase everyday mental lapses, which in turn reduces psychological health.”
“Other studies have found an association between fruit and vegetables and mental health, but few have looked at fruit and vegetables separately—and even fewer evaluate both frequency and quantity of intake.”
“Both fruit and vegetables are rich in antioxidants, fiber and essential micronutrients which promote optimal brain function, but these nutrients can be lost during cooking. As we are more likely to eat fruit raw, this could potentially explain its stronger influence on our psychological health.”
“It is possible that changing what we snack on could be a really simple and easy way to improve our mental well-being. Conversely, it is also possible that the forthcoming restriction of processed snack foods at checkouts, due to come in this October, could not only improve the country’s physical health, but mental health too.”
“Overall, it’s definitely worth trying to get into the habit of reaching for the fruit bowl.”
Frequency of fruit consumption and savoury snacking predict psychological health; selective mediation via cognitive failures
While there is growing interest in the link between diet and psychological health, there is a surprising lack of studies investigating the precise associations between nutrient-rich foods (such as fruit and vegetables) v. nutrient-poor foods (such as energy-dense savoury and sweet snacks), and psychological health.
Similarly, the psychological processes underpinning the relationship between dietary intake and psychological health remain unclear. Hence, the present study aimed to explore the relationship between dietary consumption and psychological health, with cognitive processes as a theoretical mediator.
This cross-sectional online study included 428 healthy adults (53 % female; mean age = 39·7 years, SD = 13·0), with participants completing a range of validated questionnaires measuring dietary habits and psychological health. Stepwise multiple regression revealed that more frequent consumption of fruit was associated with reduced symptoms of depression (β = –0·109, P = 0·025) and greater positive psychological wellbeing (β = 0·187, P < 0·001). Conversely, more frequent savoury snacking was associated with increased anxiety (β = 0·127, P = 0·005).
Further, mediation analyses revealed that more frequent consumption of savoury snacks was associated with increased symptoms of depression, stress, anxiety and reduced psychological wellbeing, via an increase in cognitive failures (ps < 0·001).
These results provide new insights on the independent associations between certain types of food and psychological health, and the psychological mechanisms that may mediate these.
Further work is now required to establish causality and determine whether these may represent modifiable dietary targets that can directly (and indirectly) influence our psychological health.