Missing Script

Get updates

Evidence Explorer · MS-N296 · Nutrition and dietary patterns · Appraised November 10, 2026

In a double-blind phase IIb trial, 3 g/day of MAG-EPA for about seven weeks increased prostate-tissue EPA but did not reduce the prespecified Ki-67 proliferation endpoint.

Evidence at a glance

  • Population: 130 men with grade-group 2 or higher prostate cancer scheduled for radical prostatectomy; 65 randomized per arm.
  • Intervention: 3 g/day MAG-EPA long-chain omega-3 supplement or placebo for seven weeks, with an observed range of four to ten weeks.
  • Primary result: tumor Ki-67 was 3.10% with MAG-EPA and 2.85% with placebo (P=.64).
  • Other findings: prostate-tissue EPA was approximately fourfold higher; among 27 cytokines, IL-7 differed.
  • Evidence label: supplement reached tissue but did not improve the primary tumor-proliferation biomarker.
  • Evidence label: Randomized negative primary biomarker result.

What was studied

This trial is a useful reminder that exposure is not efficacy. Detecting much more EPA in prostate tissue confirms delivery, but the biological endpoint the study set out to change did not improve.

The isolated cytokine finding is secondary and arose among many comparisons. It does not establish an anticancer immune effect.

What this evidence cannot establish

The preoperative exposure was brief and the endpoint was a biomarker rather than recurrence or survival. A negative Ki-67 result does not answer every possible omega-3 question, but it directly argues against claiming this formulation reduced tumor proliferation in the studied setting.

Safety and practical context

Omega-3 supplements commonly cause unpleasant taste, reflux, nausea or diarrhea. High doses may affect platelet function and warrant discussion around anticoagulants and surgery; cardiovascular trials have reported a small atrial-fibrillation increase with 4 g/day products. Food omega-3 intake and this purified formulation are not interchangeable.

Questions for the care team

  • Is the claim based on tissue exposure or on the prespecified efficacy endpoint?
  • Should the supplement be stopped before surgery or combined with anticoagulants?
  • Would a future trial need recurrence, progression or treatment-free survival rather than another surrogate?

Sources and identifiers

Funding and conflicts: Supported by the Canadian Cancer Society Research Institute (grant 702569). Authors declared no competing interests, and reported that funders had no role in design, analysis, interpretation or publication decisions.

Source access and dates: Primary reports, registries and official guidance available through the links above were checked November 10, 2026. Last literature search November 10, 2026. Fields unavailable from accessible full text are labeled not reported or not verified rather than assumed absent.

Educational evidence summary, not individualized medical advice. Restrictive diets or supplements should not replace established cancer treatment or adequate nutrition. Symptom, weight, biomarker, laboratory, imaging, pathology or animal findings do not by themselves establish tumor control, recurrence prevention or longer survival.