A recent review of fish oil studies that have been performed over the past 30 years suggests that omega 3 fatty acids are beneficial for everyone (published in the Journal of the American College of Cardiology August 2009). Studies have found that healthy people as well as patients with heart disease (heart attack, congestive heart failure, atrial fibrillation) benefit from fish oils.
Most of the positive health effects were found with trials using DHA and EPA, which are long-chain fatty acids. EPA and DHA are found in fatty fish and fish oil supplements. Not as much data is available on plant-based ALA which is found in flaxseed and other plants.
Current recommendations for omega 3 consumption:
1) Healthy people should consume at least 500 mg per day of EPA and DHA, equivalent of 2 fatty fish meals per week
2) Patients with known heart disease or heart failure should consume 800 to 1,000 mg of EPA and DHA per day
3) Patients with very high triglyceride levels may require prescription strength fish oil, should discuss with your healthcare provider