When we do epidemiologic studies and try to see what people’s habits are, one thing that seems to come out over and over again is that people who consume fish seem to have less cardiovascular disease, particularly less coronary disease. The reason for this seems to be the n-3 marine fatty acids in fish, and there is also some thinking that the same kind of fatty acids found in plants may have benefits

In a very nice study from Holland, [the researchers] took about 3200 people and did a factorial design; that is, the patient received placebo of DHA/EPA or ALA, or one or the other, in a very traditional factorial design. They followed these individuals for about 2.5-3 years and then looked at cardiovascular events.

Read more: http://www.medscape.com/viewarticle/735599?src=mp&spon=34

This proves that one has to take care of all risk factors like Hypertension, Diabetes Dyslipidemia (by means of lipid lowering drugs) in addition to Plant or Fish n-3 Fatty Acids in addition to exercise.