The Journal of Membrane Biology

, Volume 206, Issue 2, pp 155-163

First online:

Is Fish Oil Good or Bad for Heart Disease? Two Trials with Apparently Conflicting Results

  • M.L. BurrAffiliated withDepartment of Epidemiology, Statistics and Public Health, Cardiff University, Heath Park Email author 
  • , F.D.J. DunstanAffiliated withDepartment of Epidemiology, Statistics and Public Health, Cardiff University, Heath Park
  • , C.H. GeorgeAffiliated withWales Heart Research Institute, Cardiff University

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access


Two successive randomized trials examined the effect of an increased intake of fatty fish, or the use of fish oil supplements, in reducing mortality in men with heart disease. The Diet and Reinfarction Trial (DART) was conducted in 2033 men who were recovering from acute myocardial infarction (MI). Those who were advised to eat fatty fish (or who opted to take fish oil capsules instead) had a 29% reduction in all-cause mortality over the following two years compared with those not so advised. The effect appeared in the first few months of the trial. The Diet and Angina Randomized Trial (DART 2) involved 3114 men with stable angina. Advice to eat fatty fish did not reduce mortality, and taking fish oil capsules was associated with a higher risk of cardiac and sudden death. The adverse effects of fish or fish oil were restricted to men not taking β-blockers or dihydropyridine calcium-channel blockers, and were greater in those taking digoxin. Evidence from other sources strongly suggests an anti-arrhythmic action of fish oil, particularly after MI or in the presence of acute ischemia. The apparently conflicting results of the two trials may reflect different actions of n-3 fatty acids in acute and chronic conditions, together with different effects of eating fish and taking fish oil capsules. A mechanism is proposed that could account for these findings.


Fatty acids Fish Heart disease