Researchers working at the Veterans Affairs Medical Center state that DPA and DHA, primary components of fish oil, provide substantial protection against coronary heart disease. This study involved more tha six thousand middle-aged men who had samples of their blood taken between 1973 and 1976. During the next seven years, 94 of these men had a heart attack or died suddenly due to heart disease. The 94 men were matched with 94 healthy men and the fatty acid profile of their blood samples compare.