The effects of EPA and DHA enriched fish oil on nutritional and immunological markers of treatment naïve breast cancer patients: a randomized double-blind controlled trial

Randomized, double-blind, controlled trial in treatment-naive breast cancer patients newly diagnosed and awaiting surgery in Brasilia, Brazil. For the fish oil group, 18 participants were randomized; enrollment occurred between February 2012 and March 2013.

The active arm received 2 g/day of fish oil concentrate orally for 30 days, taken as 1 g capsules twice daily with lunch and dinner. Each gram provided 470 mg EPA and 390 mg DHA in ethyl ester form, with vitamin E included as an antioxidant; the fish oil product was MaxOmega 46/38 EE®.

Fish oil supplementation produced a clear omega-3 enrichment and was associated with a more favorable inflammatory profile, but it did not significantly change hsCRP, CD4+ T lymphocytes, or proinflammatory cytokines/PGE2. In the fish oil group, plasma total n-3 fatty acids increased from 3.3 [2.4-4.9] to 6.5 [4.3-8.7] (p = 0.004), EPA rose from 0.4 [0.1-0.8] to 1.5 [0.9-2.1] (p = 0.004), DHA rose from 2.5 [1.9-3.6] to 4.6 [3.4-6.2] (p = 0.007), and the n-6:n-3 ratio fell from 7.7 [5.3-9.7] to 3.8 [3.0-4.7] (p = 0.002). The authors concluded that EPA and DHA supplementation helped maintain CD4+ T lymphocyte levels and hsCRP, suggesting a beneficial immunomodulatory effect and less active inflammation.

The active arm was small (18 participants) and treatment lasted only 30 days, limiting power and durability of inference. Outcomes were largely biomarker-based rather than clinical endpoints, and several immune/inflammatory measures did not change significantly. Participants were a specific preoperative breast cancer population from one city in Brazil, which limits generalizability.