Something Fishy About Fish

Then there is the issue of mercury. All fish contain mercury, and generally the bigger the fish, there is mercury. The highest content of mercury is found in sharks (0.68 mcg per kilo), followed by the swordfish (0.64), then the needle (0.49), and tuna (0.18) . Salmon and trout tend to be very low (about 0.02 micrograms per kilo). Contrary to popular opinion that mercury contamination is not from human source, but from the bottom of the ocean where deposition of mercury from volcanic activity along the edges of tectonic plates. We've all been exposed and on average consumes 1 mcg of mercury per day from food, water and air.
The mercury problem is important only if it is you're eating a lot of large carnivorous fish or already mercury toxic, possibly from a mouthful of amalgam fillings. It is advisable to have amalgam fillings removed mercury and consume less big fish.
So, what is the bottom line of fish? Given that is a great source of protein and essential fatty acids, it is advisable to limit the consumption of large fish like tuna and swordfish meaning eat only twice a month and, when possible, eating wild Pacific salmon, followed by Atlantic salmon, then organic farmed salmon and other carnivorous fish smaller three times a week. Sardines are an excellent choice because they are small and therefore less likely to have accumulated toxins than their larger cousins.