Mercury in fish

2004 update

Fish is an excellent source of protein, omega 3 oils and iodine and has been shown to be beneficial to health, if eaten several times a week. For this reason the National Health and Medical Research Council and Australian Heart Foundation recommends we eat one to two fish meals a week. However, fish has recently been reported to contain mercury (a pollutant in the environment) - excess mercury appears to affect the nervous system causing numb or tingling fingers, lips and toes, can cause developmental delays in walking and talking in children and muscle and joint pain.

So does this mean we should avoid fish?

According to Food Standards Australia and New Zealand (FSANZ) we should continue eating several serves of fish and seafood per week but avoid fish high in mercury like: shark, swordfish (broadbill) and marlin. These are long-living predatory fish that accumulate mercury in the form of methyl mercury. Fish previously classed as high in mercury but now off the high-mercury list are ray, gemfish, ling and southern blue fin tuna. Pregnant women, women planning pregnancy and children up to six years old are also advised to restrict consumption of orange roughy (sea perch) and catfish. Nursing mothers are advised that if they want to be cautious they should also follow the advice for pregnant women. More info at: http://www.abc.net.au/rn/talks/8.30/helthrpt/stories/s940899.htm
http://www.foodstandards.gov.au/

2001

A statement from the Australian New Zealand Food Authority provides recommendations to pregnant women about consumption of fish. It recommends that pregnant women limit their consumption of fish such as shark (flake), ray, swordfish, barramundi, gemfish, orange roughy, ling, southern bluefin tuna and freshwater fish caught in geothermal waters in NewZealand to four serves per week.

In most individuals, food, and in particular fish, is the major source of exposure to mercury. Mercury can be harmful to the nervous system at high levels of exposure. Symptoms are generally not apparent until after the baby is born and tend to be quite subtle, such as delays in walking and talking. Most people are not exposed to levels of mercury high enough to be damaging, however research indicates that the unborn fetus may be more sensitive to the effects of mercury from food.

The level of mercury differs in different species of fish, however the types of fish mentioned above tend to live longer, are large in size and are at the top of the food chain, therefore they may accumulate higher levels of mercury.

This is not to discourage women from eating fish during pregnancy, as fish is a good source of protein, is low in saturated fat, and high in the good omega 3 oils. Pregnant women can eat as much other fish as they like. The National Heart Foundation of Australia recommends consuming fish twice a week for cardiovascular health benefits.

There are regulations in place that limit the amount of mercury that can be present in fish that is sold. This ensures that the majority of people are not exposed to any health risks from the presence of mercury in fish.

References

Last Updated: May 2004.