RESUMEN
OBJECTIVES: We report on the acceptability, feasibility, dose-response relationship and adherence of two nutritional strategies to improve mood (multinutrient supplements; food-related behavioural activation (F-BA)) studied in a randomised controlled depression prevention trial (the Multi-country cOllaborative project on the rOle of Diet, Food-related behaviour, and Obesity in the prevention of Depression (MooDFOOD) Trial). We also assessed baseline determinants of adherence and assessed whether better adherence resulted in lower depressive symptoms. DESIGN: Randomised controlled trial with a 2×2 factorial design conducted between 2015 and 2017. SETTING: Germany, the Netherlands, UK and Spain. PARTICIPANTS: Community sample of 1025 overweight adults with elevated depressive symptoms without a current episode of major depressive disorder. Main eligibility criteria included age (18-75 years), being overweight or obese, and having at least mild depressive symptoms, shown by a Patient Health Questionnaire Score of ≥5. A total of 76% of the sample was retained at the 12-month follow-up. INTERVENTIONS: Daily nutritional supplements versus pill placebo or an F-BA therapy, delivered in individual and group sessions versus no behavioural intervention over a 1-year period. PRIMARY AND SECONDARY OUTCOME MEASURES: Primary outcome: self-reported acceptability of the interventions. SECONDARY OUTCOMES: adherence and self-reported depressive symptoms. RESULTS: Most participants reported that the F-BA was acceptable (83.61%), feasible to do (65.91%) and would recommend it to a friend (84.57%). Individual F-BA sessions (88.10%) were significantly more often rated as positive than group F-BA sessions (70.17%) and supplements (28.59%). There were statistically significant reductions in depressive symptoms for those who both adhered to the F-BA intervention and had a history of depression (B=-0.08, SE=0.03, p=0.012) versus those who had no history of depression. Supplement intake had no effect on depressive symptoms irrespective of adherence. CONCLUSIONS: F-BA may have scope for development as a depression prevention intervention and public health strategy but further refinement and testing are needed. TRIAL REGISTRATION NUMBER: NCT02529423.