Gabe Mirkin, M.D.

The American Heart Association recommends eating at least two 
servings of fish per week. Fish, particularly cold-water, fatty fish 
such as salmon, mackerel, herring, sardines, trout and tuna, contain 
omega-3 fatty acids that help to protect against heart disease. 

Omega-3s can help prevent blood platelets from clotting and sticking 
to artery walls in the form of cholesterol-rich plaques. Most heart 
attacks happen when blood clots lodge in veins and arteries, 
preventing blood from circulating properly. Omega-3s may also help 
prevent inflammation in diseases such as rheumatoid arthritis, and 
lack of omega-3s may also cause mood disorders such as post-partum 

All seafood contains some, including non-fatty fish, such as 
halibut, flounder, perch, trout and cod. Shrimp, lobster, clams, and 
oysters also provide decent amounts of omega-3s, as do freshwater 

Wild fish are not richer in omega-3 fish oils than farm-raised 
varieties. Farm-raised fish such as salmon and trout won't grow 
without omega-3 fatty acids in their diet, so fish farmers add it to 
the fish meal. Farmed catfish and tilapia, however, do not need 
omega-3 fatty acids, so these farm-raised fish have little or no 
omega-3s. In the wild, fish get their omega-3s from algae, plankton 
and other fish that they may eat. 

You don't need to eat fish to get omega-3s. You can get omega-3s by 
eating whole grains, beans, such as soybeans and seeds. Flaxseeds 
are among the richest plant sources of omega-3s.

Many people avoid fish because of fear of mercury poisoning. Nearly 
all fish contain some amount of methyl mercury, which theoretically 
can damage nerves, particularly during fetal growth. Mercury is 
released into the air by pollution. Rainwater brings it into streams 
and oceans, where bacteria transform it into methyl mercury. Fish 
get their dose as they feed on algae and other organisms. Older, 
larger fish that eat other fish accumulate the most methyl mercury, 
so big carnivores such as swordfish and tuna pose the greatest risk 
to susceptible populations. Methyl mercury is stored in the flesh 
and there is no way to remove it.

The Food and Drug Administration recommends that pregnant women and 
women who might become pregnant, nursing mothers, and young children 
not eat shark, swordfish or large tunafish. They should eat plenty of other types of fish and shellfish. If a pregnant woman chooses to avoid seafood, she should make sure she gets plenty of omega-3's from seeds such as flaxseed, or from supplements. The FDA does not recommend any limits on fish consumption for the general population.
Omega-3's from plants 

Checked 10/20/12