Surprised that there is just one mention in this entire thread of Dr. Esselstyn[1] and Dr. Dean Ornish[2] - two doctors who deserve more attention in any discussion on the topic of preventing heart disease. They have published research and studies showing that it is possible to prevent and actually reverse heart disease - even in advanced cases of artery blockage - by strict diet and lifestyle changes. President Clinton has adopted their recommended diet after his coronary bypass surgery. Highly recommend reading their research studies and books on the subject.
[1] http://en.wikipedia.org/wiki/Caldwell_Esselstyn
[2] http://en.wikipedia.org/wiki/Dean_Ornish