Fish type, mercury and heart benefits

Fish, omega-3 fatty acids and heart: Fish contain high amounts of omega-3 fatty acids (eicosapentaenoic acid and docosahexaenoic acid) which have been proven to be cardioprotective, i.e. good for heart. They prevent heart attacks.  Studies suggest that there is 29% reduction in mortality over 2 years inpatients who have had heart attacks.

The evidence is strong enough for the American Heart Association to recommend increased intake of omega 3-fatty acids. The good news is that mercury content of all the fish is not the same. The mercury content of predatory fish is much higher because they eat other fish containing mercury and indirectly attain much higher levels mercury than the fish at the lower end of the food chain.

The beneficial effect if fish intake can be demonstrated with as few as 1 fish per week, and greater intake provides even greater protection.

Fish, mercury and toxicity: The benefits of fish intake are tempered by the concern over mercury intake through fish and the resultant potential for neurotoxicity.

Low versus high mercury fish: The good news is that mercury content of all the fish is not the same. The mercury content of predatory fish is much higher because they eat other fish containing mercury and indirectly attain much higher levels mercury than the fish at the lower end of the food chain.

Identifying low versus high mercury fish: Sardines, salmon, and shrimp have lower mercury content than the predatory sharks, tuna, sword fish and orange roughy.

Farmed fish: Even more importantly, the farmed fish have the lowest mercury content while providing the same benefit.

Limiting the mercury content: The exposure to mercury can be lowered by limiting the amount of fish ingested and eating the fish with lower mercury content.

Recommendations for fish intake: Institute of Medicine provides conservative recommendations regarding fish consumption. Non-pregnant persons may eat 1 predatory fish meal and 2-3 low mercury fish meals per week. Pregnant women should not eat more than 1 predatory fish meal per 2 weeks; however they may eat other fish 2-3 times per week.

Both wild and farmed fish are beneficial.

Above is based on an article in Nature Clin Practice (2008).