Eat fish-it's good for you, especially those with high omega-3 content. But watch out for the mercury and PCBs found in some varieties. And did you check if that seafood is on the endangered species list?

No wonder people are confused by the conflicting health and nutrition advice regarding seafood. While medical consensus has been reached on the benefits of eating seafood-it has been proven to be beneficial in combating maladies ranging from depression to breast cancer-some very real concerns make it important to know which kinds of seafood are environmentally sound.

Some staples of the seafood aisle and restaurant menus-including orange roughy, Atlantic halibut and Chilean sea bass-are in danger of overfishing. And several other species such as swordfish, bluefish and shark are known to have high degrees of environmental contaminants.

Fish Lower On The Food Chain Are The Healthiest

"Generally, fish lower on the food chain are the healthiest to eat," says esteemed nutritionist Keri Glassman, author of "The Sardine Diet." Her book outlines the myriad health benefits of sardines and seafood in general, and proposes a heart-healthy and low-calorie diet aimed at improving overall health.

Glassman may be a bit biased, but sardines are considered to be among the healthiest seafood available, as they are low in environmental contaminants, are abundant in the wild, and have a high concentration of omega-3 fatty acids.

Which Seafoods Are Best?

According to a recent "New York Times" article, several environmental organizations provide guidelines on which seafoods are best to eat, and in addition to sardines include Atlantic mackerel, anchovies, Pacific salmon, sole and butterfish.