Fish oil may reduce the risk of heart attack and improve overall heart health. Researchers at the Vet. Affairs Medical Center report that dha and epa, major components of fish oil, offer substantial protection against coronary heart disease. Their study involved over 6,000 middle-aged men. 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 s.