Dietary Omega-3 Fatty Acid Intake, Anxiety, and Depression Among University Students in the UK: An Exploratory Cross-Sectional Study

Background: Omega-3 fatty acids may be relevant to mental health, but evidence among university students remains limited. This small exploratory cross-sectional study examined associations between estimated dietary omega-3 intake and anxiety and depressive symptoms among university students in the UK. Methods: Data were collected between February and May 2025. Habitual dietary EPA + DHA and alpha-linolenic acid (ALA) intakes were estimated using an adapted omega-3 food-frequency questionnaire, while 24-h dietary recall was used to estimate energy intake. Anxiety and depressive symptoms were assessed using the GAD-7 and PHQ-9. The primary association between estimated dietary EPA + DHA intake and GAD-7 score was examined using linear regression adjusted for age, sex, energy intake, and alcohol use. Analyses involving ALA and PHQ-9 were exploratory. Results: Of 96 students recruited, 50 (52.1%) were analysed after 46 exclusions, most commonly for omega-3 supplement use (n = 21) or diagnosed mental-health conditions (n = 16). Mean GAD-7 and PHQ-9 scores were 6.66 ± 4.73 and 7.02 ± 4.76, respectively. In the fully adjusted model, each additional 100 mg/day of estimated dietary EPA + DHA intake was associated with a 0.325-point lower GAD-7 score, but the association was not statistically significant (B = −0.325; 95% CI: −0.725 to 0.074; p = 0.108). Exploratory analyses found no significant associations of estimated dietary EPA + DHA or ALA intake with anxiety or depressive symptoms. The inverse coefficient lost statistical significance after full adjustment, and the log-transformed coefficient reversed direction and remained non-significant, arguing against a consistent dose–response relationship. Conclusions: Estimated dietary EPA + DHA intake showed an inverse but inconclusive association with anxiety symptoms in this small exploratory sample. These preliminary findings are hypothesis-generating and require confirmation in larger longitudinal studies using repeated dietary assessments and biomarkers of omega-3 status.