July 2007 Edition
Healthwise: Current Information on Mercury and Fish Consumption


Current Information on Mercury and Fish Consumption


By Suzanne Berryman, R.D.


Fish is an excellent source of high-quality protein and low in saturated fat making it a healthy food choice. But, there has been so much information

in the media lately about mercury and fish- is it still safe to serve in your restaurant?


Health Canada has recently completed a scientific review on mercury in fish, and is putting additional measures in place to protect Canadians while encouraging them

to consume at least two servings (75 grams each) of fish each week according to the new Canada's Food Guide. 


Types of Fish that Should be Eaten Less Often:


Health Canada,s standards for mercury in fish were already some of the most stringent in the world.  They have identified certain predatory fish as being of more concern when it comes to mercury in fish.  Fish can accumulate mercury in their muscles through absorption from the surrounding water but mostly from the prey that they eat.  This mercury can also concentrate up the food chain.  Therefore, predatory fish that eat lots of other fish tend to contain higher levels of mercury. 


These fish include fresh/frozen tuna, shark, swordfish, marlin, orange roughy and escolar.  Canadians who like to consume these types of fish can continue to do so, but should limit their consumption to the amount specified in the table below.


Canned Tuna:


Canned tuna, especially light canned tuna, is one of the most popular types of fish for many Canadians. Canned light tuna contains other species of tuna such as skipjack, yellowfin and tongol, which are generally low in mercury. 

However, for those who consume large amounts of canned albacore tuna, there is some potential for exposure to higher levels of mercury than is considered acceptable.  Because of this, Health Canada has issued advice for children and some women on the consumption of albacore tuna in the table below.  This advice only applies to albacore tuna and does not apply to canned light tuna which contains relatively low amounts of mercury.


Satisfying Your Seafood Patrons:


While tuna may be high in mercury when consumed in large quantities, there are other fish in the sea.  Rather than eliminating fish from your menu, serve up other varieties that contain

less mercury such as shrimp, scallops and calamari.  Fresh water fish such as trout is another way to serve a white-fleshed fish on the menu instead of orange roughy which could be high

in mercury. 


Another way to maintain fish on your menu while keeping your customer's health in mind is to be careful of the quantities.  Instead of serving a large tuna or swordfish steak, ensure the sizing meets or is less than the 150 grams recommended by Health Canada. You may even want to consider serving smaller chunks of the fish as part of a pasta dish such as seafood linguini. This way your patrons can still have their favourite fish without the risk.  


Keep in mind Health Canada still considers fish as a healthy alternative and an excellent source of protein.  With a little creativity and some awareness of which varieties are the most risky, fish can remain a staple on your menu for years to come.


            Health Canada            General            Women who are pregnant,      Children          Children

            Recommendation        Population       breastfeeding or who may         5-11                1-4

                                                                              become pregnant            years old        years old

            Fresh/Frozen Tuna,     150 g                                150g                      125g                 75g

            Shark, Swordfish,       per week                          per month              per month        per month

            Marlin, Orange

            Roughy & Escolar                                            

            Canned Albacore        No limit                               300g                      150g                  75g

            Tuna                                                                   per week                  per week          per week

Source:  Health Canada