Heavy metals in fish?

Question

I would very much like to cut down on my consumption of red meat. I'm interested in adding more fish to my diet, but my boyfriend and I are concerned about the levels of heavy metals in fish. How can I minimize the incidence of heavy metal in the fish that I buy? What should I do to make sure that the fish I eat will be good for me? Are there specific places in the world from where the fish is more "pure" than other places? What types of fish are usually affected most by heavy metals in the environment? Is there a chart or graph somewhere online that I could look up?

Answer 1

I believe salmon has lower levels, possibly because they start and end their lives in fresh water.

Fresh water fish are also clean. Trout, bass, etc...

Answer 2

Nearly all fish have some trace amounts of heavy metals, but the metals don't reach dangerous concentrations in all fish. The fish with the highest levels of are at the top of the food chain, and the lowest levels at the bottom. Metals bio-accumulate in fish that eat other fish, so the larger predatory fish have the highest amounts of metals. The large predators include shark, tuna, salmon (except for wild Alaskan salmon only), mahi-mahi, and swordfish.

Farmed tilapia and wild Alaskan salmon are probably the safest fish on the market. There are many more OK species in the link:

Answer 3

Don't buy fish wearing Iron Maiden T shirts
I'd imagine a guitarfish would be affected by heavy metal

Answer 4

I don't think I have much to add compared to the previous posts, but I will say I think catfish are pretty safe since they feed on the muck on the bottom of the water. They're not predators, so their intake of metals should be very low.

Also, for similar reasons, shrimp & crabs should be pretty safe too.

Answer 5

Fish’s bodies absorb toxic chemicals in the water around them, and the chemicals become more concentrated as they move up the food chain. Big fish eat little fish, with the bigger fish (such as tuna and salmon) absorbing chemicals from all the other fish they eat. Fish flesh stores contaminants, such as PCBs, which cause liver damage, nervous system disorders, and fetal damage; dioxins, also linked to cancer; radioactive substances like strontium 90; and other dangerous contaminants like cadmium, mercury, lead, chromium, and arsenic, which can cause health problems ranging from kidney damage and impaired mental development to cancer.These toxins are stored in the body fat of humans who eat fish and remain in their bodies for decades.

The best way to minimize metals being absorbed in your body by way of fish is to eat smaller fish (less metals in the fish themselves, therefore less in you), and wild fish.

limit consumption of many types of freshwater sports fish, which are often badly polluted with mercury, along with such ocean species as shark, swordfish and fresh and frozen tuna. Large, long-lived ocean fish are a worry because they have time to build up high amounts of the contaminant.

The better choice would be cold-water species such as salmon, which are generally low in the metal but high in fatty acids. Canned light tuna is a mix of different varieties of the fish that have lower levels of mercury.

Here's a calculator for Mercury Levels

http://www.gotmercury.org/english/advanced.htm

Albacore tuna

Women who are or who may become pregnant, or who are breastfeeding, can eat up to four servings of canned albacore tuna each week. One serving is equal to 75 grams, 2 ½ ounces, 125 millilitres or ½ cup.

Children between one and four years old can eat up to one serving of albacore tuna each week.

Children between five and 11 years old can eat up to two servings of albacore tuna each week.

'Light' tuna

Canned albacore tuna, also known as 'white' tuna, is not the same as canned 'light' tuna. Canned light tuna contains other species of tuna such as skipjack, yellowfin, above, and tongol, which are relatively low in mercury. Canned light tuna also tends to be lower in cost relative to albacore tuna. Based on lower mercury levels, Health Canada does not consider it necessary to offer any consumption advice specific to canned light tuna.

Other fish

For other types of fish that can contain high levels of mercury, the federal agency recommends:

Canadians should limit consumption of swordfish (above), shark and fresh and frozen tuna to one meal per week. Pregnant women, women of child-bearing age and young children should eat no more than one such meal per month.