Reseaech                                                                                                                For the research, a team from the School of Psychology at Aston conducted a cross-sectional online survey of 428 adults from across the UK who answered a range of validated questionnaires measuring dietary habits, psychological health, and everyday cognitive capacity. The participants were 53% female, 90% White, with a mean age of 39.7 years and no major health problems, food allergies or eating disorders. Mean BMI was 26.0, 53% were normal weight, and 86% rated their general health as good to excellent.

They were asked about their consumption of fruit, vegetables, sweet and savoury snacks (such as crisps, biscuits, cakes, chocolate, and sweets), anxiety, stress and depression, as well as overall mental well-being etc.

Results were published in the British Journal of Nutrition, showed:

• Both frequency of fruit consumption and portions of vegetables consumed negatively predicted depression scores
• Frequency and portions of fruit consumption positively predicted psychological wellbeing scores
• Frequency of vegetable consumption did not predict psychological health
• Frequency of sweet and savoury snacking positively predicted anxiety scores
• Frequency of savoury snacking positively predicted stress

Frequency                                                                                                            Within these models, fruit frequency was a significant negative predictor of depression and a significant positive predictor of psychological wellbeing.

The frequency of savoury snacking was a significant positive predictor of anxiety. After including the covariates, all other models for snacking, vegetable and fruit portions were no longer significant predictors of psychological health.

The authors commented that both nutrient-rich fruit and nutrient-poor snacks appeared to be linked to psychological health, in opposite directions, whereas there was no direct association with eating vegetables after taking demographic and lifestyle factors into account. In contrast, the more often people ate fruit, the lower they scored for depression and the higher for mental wellbeing, independent of the overall quantity of fruit intake.

Eating Fruit Raw May Maximise Nutrients

The report goes on to point out that fruit and vegetables “are often consumed in different environmental contexts” – vegetables are typically eaten as part of a meal at home, whereas fruits are often consumed as snacks outside the home and throughout the day. Moreover, fruits are more often eaten raw, which may maximise the absorption of nutrients.

Lead author, PhD student Nicola-Jayne Tuck, a postgraduate researcher in the School of Psychology at Aston University, said: “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, fibre 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.”

She further told Medscape UK: “We did not compare the form in which fruit and veg was consumed in the current study, but we know from randomised-controlled trial evidence that consuming fruit and veg raw (including carrots, eaten as snacks) may have a more potent influence on psychological wellbeing compared with processed fruit/veg consumption.”

What it all means