Diet, mood and emotions

This 2017 study recruited 171 low fruit and vegetable (FV)-consuming young adults (aged 18-25), and randomly assigned them into one of three conditions: an ecological momentary intervention (EMI) involving text message reminders to increase FV intake as well as vouchers to buy FV; fruit and vegetable intervention (FVI) providing the subjects with two additional servings of FV on top of their regular diet; and the control condition which was the participants’ normal day-to-day diet. The purpose was to research the effects of these 14-day interventions promoting greater FV consumption. Depressive and anxiety symptoms were measured pre- and post-intervention while positive mood, vitality, flourishing and flourishing behaviors (curiosity, creativity, and motivation) were documented on a nightly basis using a smartphone survey. Blood samples were taken before and after the interventions took place to examine vitamin C and carotenoid levels. In addition, psychological expectancies about the benefits of FV were taken to test as mediators of psychological change. The results showed improvements in psychological well-being (increases in flourishing, vitality and motivation) in only the group that received 2 supplementary portions of fruits and vegetables (the FVI intervention group), across the 14 days relative to the other condition groups. Intervention benefits were not mediated by vitamin C, carotenoids, or psychological expectancies but this study demonstrated young adults react more positively to provision of high-quality, fresh fruits and vegetables, rather than reminders and vouchers to encourage increased FV intake. Significant short-term improvements in their psychological well-being were seen, which provides early proof-of-concept that giving young adults fruits and vegetables to eat can have psychological benefits even over a short period of time.

(2016) In this study, 541 Iranian students took part in online questionnaires to analyze their measure of contentment associated with their fruit and vegetables intake, and whether they skipped breakfast or not. The results showed several statistically significant links, namely, greater levels of happiness were achieved in those who ate breakfast, consumed more fruit and vegetables, and who ate an increased number of meals a day.

(2015) This was a correlational study that aimed to investigate whether there is a relationship between fruit and vegetable intake and our “eudaemonic” state (which is a mental state that relates to happiness and includes feelings of curiosity, creativity, happiness, engagement, and purpose). The study had 405 young adults complete an internet diary for 13 days which recorded their mood (positive or negative), and the amount of fruit, vegetables and less nutrient-dense foods they consumed (i.e., chips and sweets). A significant relationship between eating fruits and vegetables and higher eudaemonic well-being was found. This study contributes to the growing body of knowledge that helps us understand the relationship between diet and mental health which is not only created by lack of disease, but also by presence of well-being.

(2019) Adherence to the “high quality” Mediterranean diet (MD) and mental well-being were examined in a group of Spanish children and adolescents. They were cross-sectionally analysed at the start of the study and after a 2-year interval (533 children and 987 adolescents initially, 527 children and 798 adolescents at follow-up). The aim of the study was to assess the relationship between MD adherence (using KIDMEX Index) and psychological health (with the Positive and Negative Affect Schedule and the KIDSCREEN-10 questionnaire) by adopting a multi-level, mixed-effects linear regression model. Cross-sectional analysis highlighted that increased MD adherence behaves as a protective factor for positive mental well-being.

(2019) Health-related quality of life (HRQOL) and subjective happiness of 527 Spanish adolescents were evaluated along with their adherence to the Mediterranean Diet (MD). The use of Pearson’s correlations and hierarchical linear regression analysis supported a positive association of MD adherence with higher HRQOL and subjective happiness scores. Several subscales of HRQOL such as emotional well-being, mood and emotions, financial resources and social acceptance were seen to have a mediation effect in the association between MD adherence and subjective happiness after employing the macro PROCESS for SPSS. Ferrer-Cascales et al encourages further research on other factors that may mediate the association found in this study.

(2019) This study examined whether there was a correlation between diet and mood during menstrual cycles in Chinese University students. Through random sampling, 88 academics from Guangzhou were selected to take part in 2 self-administered questionnaires: one documented their eating habits; another evaluated level of negative mood. Multiple logistic regression analyses were used to discover statistically significant lower mood scores during the menstrual phase when consumption of tea, coffee, and carbonated beverage was higher. During the premenstrual phase, worsening of mood was associated with banana and red Chinese dates intake (statistically significant). This study suggests specific foods and diets may influence mood in post-pubescent women.

(2013) This study looked at whether positive affect (mood) plays a role in people consuming healthier food. The authors wanted to understand whether positive moods drive us towards selecting healthier foods. Data was collected from the daily diaries of 281 healthy young adults across 21 days. Their food intake and positive and negative mood was recorded. Analysis of daily associations between diet and mood revealed a significant increase in fruit and vegetable consumption in adults who experienced positive moods. The results also demonstrated that fruit and vegetable intake could influence psychological mood experienced the following day, and to an even greater extent when 7-8 portions of F+V were consumed.

(2017) This was a correlational study examined the association between dietary intake quality and depressive symptoms in female university students. This population (female young adults) is at a greater risk for developing both unhealthy lifestyle habits and depressive symptoms, and therefore, it is important to identify whether consuming healthy food is in any way associated with the mental health of this population. The dietary intake of 141 female university students was collected in the fom of 3-day food journals. The students were assessed for depressive symptoms by questionnaire. Results showed that increased depression scores positively associated with the consumption of a low-nutrient diet in this sample population. Editor’s note: see Francis et al’s study (CNP’s featured Parent Library study) which is the first study to demonstrate the ability of poor diet to cause depressive symptoms in young adults.

Positive effects of a healthy snack (fruit) versus an unhealthy snack (chocolate/crisps) on subjective reports of mental and physical health: a preliminary intervention study

Mediterranean Diet and the emotional well-being of students of the Campus of Melilla (University of Granada)

Diet quality and feelings of worry, sadness or unhappiness in Canadian children

Bidirectional associations between psychosocial well-being and adherence to healthy dietary guidelines in European children: prospective findings from the IDEFICS study.

Effects of acute blueberry flavonoids on mood in children and young adults