Higher Dietary Omega-3 Intake Linked to Lower Prostate Cancer Risk, But Mortality Link Follows a U-Shaped Pattern

This large study followed over 30,000 men aged 55-74 for at least 7 years as part of a major U.S. cancer screening trial. Researchers used food questionnaires to estimate how much omega-3 fatty acids (EPA, DPA, and DHA) each man consumed through his diet, then tracked who developed prostate cancer and who died from it.

Men with higher dietary omega-3 intake had a modestly lower overall risk of developing prostate cancer, though this finding was borderline in terms of statistical significance. When looking at prostate cancer deaths specifically, the pattern was more complex: risk of death dropped as intake rose up to about 0.4 grams per day, but intakes above that threshold were associated with an increased mortality risk.

Using a statistical technique called restricted cubic spline analysis, the researchers identified a ‘sweet spot’ of roughly 0.15 to 0.40 grams of omega-3s per day from food sources, where mortality risk appeared lowest. This suggests a possible U-shaped relationship rather than a simple ‘more is better’ pattern.