The association of diet quality with the mental health of students during their transition to university.

University students are at risk of experiencing mental health and diet quality problems during their transition to university. This study aimed to examine the bidirectional associations between the diet quality and mental health of students during their transition to universities in the UK, and the impact of the transition on diet quality and mental health. The study adopted a cross-sectional design and took place during the first semester of year 2021-2022. Participants were first year undergraduate students at four UK universities, living at student halls. They were invited to participate by completing online surveys, including a diet quality instrument (Short Form Food Frequency Questionnaire), a mental health instrument (Depression Anxiety and Stress Scale) and a quality of transition instrument (College Adjustment Questionnaire). Results showed that a healthy diet was associated with good mental health (b = -3.46, 95% CI [-6.14, -.78]). Unfavourable mental health was associated with having an unhealthy diet (b = -.01, 95% CI [-.02, -.00]). Transition did not moderate the relationship between diet quality and mental health of students, or vice versa (ps> .05). Preliminary analyses showed a significant direct effect of good quality of transition to university on good mental health (b = -1.51, 95% CI [-1.88, -1.13]), but did not have an indirect effect via diet quality; there were no significant direct or indirect effects on diet quality, however larger studies are needed to replicate these preliminary analyses. Our current findings can inform university policies and health education research, and further research is needed to determine whether interventions to improve diet quality at the university level could reduce mental health issues, and whether interventions to support students under stress may lead to healthier dietary habits. Cross-sectional studies cannot determine the directionality of effects, hence longitudinal studies are required to enhance our understanding of the relationships between diet quality and mental health over time.