How strong is the evidence for Omega-3?

The cardiovascular evidence for omega-3 supplementation is a useful case study in scientific nuance: a Cochrane review found little to no clear benefit for primary or secondary cardiovascular disease prevention, while a separate, larger meta-analysis of 13 randomized trials covering over 127,000 participants and dose-response analyses found modest but real reductions in cardiovascular events — the two conclusions differ mainly by which trials and doses are emphasized. That evidence is currently rated moderate (55/100), built on 9 published studies, including 9 meta-analyses -- a reasonable base, but not yet enough for full certainty.