Essential fatty acids come in two types, omega-3 fatty acids and omega-6 fatty acids. They're called "essential" because they're essential to good health, but are not produced in the body and must be obtained through diet.
As Americans consume far too many of the omega-6 fatty acids found in meat, animal products and common cooking oils, the awareness for greater amounts of omega-3 EFAs has increased in recent years. Although omega-6 EFAs and omega-3 EFAs should ideally be present in our diets at a ratio of 3:1 respectively, it's as high as 40:1 for some Americans, which is why obesity is a national epidemic.
In 2004, the FDA recognized EFAs for their potential in supporting cardiovascular health, and studies by the American Heart Association suggest that diets rich in EFAs may result in a number of positive health effects.