Mercury Levels In Fish

We need to have an adequate intake of omega 3 fatty acids, yet at the same time, we need to avoid mercury in fish.

How do we achieve this?

One way is to only consume fish that is low in mercury levels.

Mercury has been found in studies to reduce the effect of the benefits of fish oils in terms of heart protection effects.

So while the benefits of fish and fish oil are important, it is also important to select the types of fish that have abundant omega 3 fatty acids, but also have the lowest levels of mercury.

An increasingly used alternative, which may be more convenient, is to choose a quality fish oil supplement that has been certified safe in relation to mercury, PCBs and other environmental compounds. The other advantage is that a fish oil capsule contains a consistent amount of omega 3 fatty acids.

Here is a list of fish that have been found by the FDA in the US to have the highest levels of mercury:

The fish with the lowest levels of mercury are:

Source: Adapted from the FDA, USA: www.cfsan.fda.gov/~frf/sea-mehg.html

Note that fresh or frozen tuna, and also for canned tuna of other species, were classified to have mercury content that was in between the highest and lowest:

For further detail, including 2004 updates and how levels of mercury have changed over time for various fish species, visit: www.cfsan.fda.gov/~frf/seamehg2.html

To find out more about fish oil capsules as an alternative to eating fish, see the page which on fish oil capsules.

Fish consumption and breast feeding and pregnant women

Pregnant and breast feeding women may need to take special care when it comes to consuming large amounts of fish during pregnancy.

Here is an excerpt taken from the advice from the FDA and EPA of the US, for women who might become or who are pregnant, breast feeding mothers, and young children:

"Nearly all fish and shellfish contain traces of mercury. For most people, the risk from mercury by eating fish and shellfish is not a health concern.

Yet, some fish and shellfish contain higher levels of mercury that may harm an unborn baby or young child's developing nervous system.

By following these 3 recommendations for selecting and eating fish or shellfish, women and young children will receive the benefits of eating fish and shellfish and be confident that they have reduced their exposure to the harmful effects of mercury.

1. Do not eat Shark, Swordfish, King Mackerel, or Tilefish because they contain high levels of mercury.

2. Eat up to 12 ounces (2 average meals) a week of a variety of fish and shellfish that are lower in mercury.

- Five of the most commonly eaten fish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish.
- Another commonly eaten fish, albacore ("white") tuna has more mercury than canned light tuna. So, when choosing your two meals of fish and shellfish, you may eat up to 6 ounces (one average meal) of albacore tuna per week.

3. Check local advisories about the safety of fish caught by family and friends in your local lakes, rivers, and coastal areas. If no advice is available, eat up to 6 ounces (one average meal) per week of fish you catch from local waters, but don't consume any other fish during that week.

Follow these same recommendations when feeding fish and shellfish to your young child, but serve smaller portions."

From: FDA USA 2004: www.cfsan.fda.gov/~dms/admehg3.html

So, the benefits of fish oil is acknowleged, and at the same time, this is prudent advice for women who are pregnant or who are breastfeeding.

So it's helpful to be generally aware of the mercury levels in fish.

A similar source to fish oil is code liver oil. There are differences however between fish oil and cod liver oil.