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The Dish on Fish

Article written by Christine Arulappen.

“An apple a day keeps the doctor away!”

Currently instead of trying to eat more fruit we are encouraged to eat more fish! And many nations have been listening with an increase in fish consumption per person per year.3 Indeed the nutritional benefits are widely recognised. Fish is a great source of quality protein and contains omega 3 fatty acids “the good foods”, vitamin D and iodine.2 Evidence also shows that regular intake of “good fats” from oily fish (salmon, herring and sardines) can lower our risk of developing cardiovascular diseases.5 However, some fish are higher in contaminants and these contaminants may be detrimental to our health.

Contaminants found in fish

Levels of methyl mercury (a form of mercury), PCBs (organic chlorine compounds) and dioxins (by-products of waste incineration, paper bleaching and production of plastics and pesticides) have been found in long-living predatory fish such as sword fish, marlin, flake, orange roughy, sea perch and catfish. 

Contaminants and our health

Although the health affects of long-term low-level exposure to mercury (our current exposure through regular fish consumption) remain less researched, high levels of mercury exposure are clearly documented.  Research indicates:

  • High levels of mercury may result in cognitive and nervous system dysfunction5
  • Animal studies and some human studies indicate that PCBs may be carcinogenic and have been linked to immune and nervous system effects on the body.
  • Methyl mercury readily crosses the placenta of pregnant woman and can affect the child’s brain and nervous system development, affecting learning and behaviour.5

Pregnant women and children under 6 years

The concern has been enough to warrant giving independent fish recommendations to pregnant women. Pregnant women and children under 6 years of age should only consume (of high contaminant risk fish):

  • 1 serve per week of orange roughy and catfish and no other fish that week OR
  • 1 serve of flake/swordfish and marlin and no other fish that fortnight.1

Confused?

Perhaps the very thought of dining at your favourite seafood restaurant now leaves a metallic taste in your mouth? Or perhaps you’re unsure if you should be eating fish at all. According to recommendations you should continue to eat 2-3 serves a week but limit flake, swordfish and marlin to 1 serve (150g) per week with no other fish that week.1

Can I reduce my exposure?

The simple answer is yes. Here are some tips:

  • Keep your intake of the long-living predatory fish to a minimum. 
  • Instead enjoy blue mackerel, John Dory, ocean trout, small oily fish (sardines, anchovy, herring), Atlantic salmon, blue eye cod, bream, flathead, mullet, snapper and whiting.

When shopping pay closer attention to the labelling of predatory fish.  Things to look out for is:

  •  Whether the fish is farmed or wild.
  • The country of origin

Research shows that PCBs and dioxins are more highly concentrated in farmed compared to wild salmon and that farmed salmon from Europe are higher in these contaminants compared to fish from North or South America.4

Eating fish provides many health benefits and should be included in your diet. However the contaminants in predatory fish are a health concern for pregnant women, and also a contentious issue for the rest of us.  So when purchasing fish or choosing the ‘Fish of the Day’ if dining out, consider choosing options that reduce your exposure to these contaminants.

 

 

References

  1. Food Standards Australia New Zealand, 2010.  Advice on Fish Consumption [Online].  Available at http://www.foodstandards.gov.au/_srcfiles/brochure_mercury_in_fish_0304v2.pdf [Accessed 30th July 2010].
  2. Food Standards Australia New Zealand, 2004.  Mercury in Fish Further Information [Online]. Available at http://www.foodstandards.gov.au/_srcfiles/FS_Mercury_in_fish_final.pdf [Accessed 29th July 2010].
  3. Food Standards Australia New Zealand, 2005.  Report on a Survey of Chemical Residues in Domestic and Imported Aquacultured Fish [Online].  Available at http://www.foodstandards.gov.au/_srcfiles/Chemical%20Residues%20in%20Fish%20Survey.pdf [Accessed 29th July 2010].
  4. Hites, Ronald A., 2004.  Global Assessment of Organic Contaminants in Farmed Salmon. Science [Online] 303(226) p.226-229.  Available at http://alaskaoceans.org/salmon.pdf [Accessed 29th July 2010].
  5. Mozaffarian, Darius and Rimm Eric B., 2006.  Fish Intake, Contaminants, and Human Health - Evaluating the Risks and the Benefits.  JAMA [Online] 296(15) p. 1885-1898.  Available at  http://jama.ama-assn.org/cgi/reprint/296/15/1885?maxtoshow=&hits=10&RESULTFORMAT=&fulltext=Contaminants+in+Fish&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT  [Accessed 29th July 2010].


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Last updated 10/26/2010 11:13:30 AM