Effects of omega‐3 supplementation on psychological symptoms in men with prostate cancer: Secondary analysis of a double‐blind placebo‐controlled randomized trial

BACKGROUND: In the general population, a higher omega‐3 polyunsaturated fatty acids intake is associated with lower levels of several psychological symptoms, especially depression. However, the existing evidence in cancer is equivocal. METHODS: This phase IIB double‐blind, placebo‐controlled trial was aimed at comparing the effects of eicosapentaenoic acid monoacylglyceride (MAG‐EPA) supplementation and high oleic acid sunflower oil (HOSO; placebo) on depression levels (primary outcome) and other symptoms (anxiety, fear of cancer recurrence, fatigue, insomnia, perceived cognitive impairments; secondary outcomes). Participants, recruited in a prostate cancer clinic, were randomized to MAG‐EPA (3.75 g daily; n = 65) or HOSO (3.75 g daily; n = 65) for 1 year post‐radical prostatectomy (RP), starting 4–10 weeks before surgery. Patients completed self‐report scales at baseline (before RP) and 3, 6, 9, and 12 months after: Hospital Anxiety and Depression Scale (HADS), Fear of Cancer Recurrence Inventory (FCRI), Insomnia Severity Index (ISI), Fatigue Symptom Inventory (FSI), and Functional Assessment of Cancer Therapy—Cognitive Function (FACT‐Cog). RESULTS: Analyses showed significant reductions in HADS‐depression, HADS‐anxiety, FCRI, ISI, FSI‐number of days, and FACT‐Cog‐impact scores over time. A significant group‐by‐time interaction was obtained on FACT‐Cog‐Impact scores only; yet, the temporal change was significant in HOSO patients only. CONCLUSIONS: Several symptoms significantly decreased over time, mainly within the first months of the study. However, MAG‐EPA did not produce greater reductions than HOSO. Omega‐3 supplementation does not seem to improve psychological symptoms of men treated with RP.