Fish and mercury FAQs

On this page

• 2. What are some of the health benefits of fish?
• 3. Should I eat fish at all during pregnancy?
• 4. Which fish have lower levels of mercury and can safely be included in my diet?
• 5. Should I avoid eating fish if I am breastfeeding?
• 6. Should I be giving fish to my young children?
• 7. Is canned tuna and salmon safe to eat regularly?
• 8. Does processing or cooking reduce mercury levels?
• 9. What if I eat more than 2-3 serves of fish per week?
• 10. What if I had been eating more than 2-3 serves of fish in the past – how long before my mercury levels return to normal?
• 11. What about fish oil products?
• 12. Is other seafood such as crustacea or molluscs a concern?

Mercury occurs naturally in the environment and accumulates in the aquatic food chain, including fish, as methyl-mercury. This means all fish contain some methyl-mercury.

The good news is that most fish in Australian waters have very low mercury levels.

It is important to note that mercury from fish is generally not a health consideration for most people – it is only an issue for women planning pregnancy, pregnant women, breastfeeding women and children under six.

2. What are some of the health benefits of fish?

There are many benefits from eating fish. Fish are low in saturated fat and are an excellent source of protein, essential Omega 3 fatty acids, iodine and some vitamins.

Omega 3 is important for the development of the central nervous system in babies, before and after they are born.

Australian Dietary Guidelines recommend eating a variety of protein-rich foods including fish, meats, poultry, eggs, nuts and legumes.

3. Should I eat fish at all during pregnancy?

Yes! Fish is a highly nutritious food. As mentioned, fish is an excellent source of nutrients such as Omega 3 as well as vitamins. These nutrients provide important health benefits for you and your baby.

Fish are a valuable source of protein, minerals, vitamin B12, iodine, and are low in saturated fat.

By being informed about mercury and knowing the kinds of fish to limit (see table), you can avoid any potential harm from mercury while enjoying the many health benefits of fish.

Pregnant & breastfeeding women & women planning pregnancy 1 serve equals 150g	Children (up to 6 years) 1 serve equals 75g
2-3 serves per week of any fish and seafood not listed below
OR
1 serve per fortnight of Shark (Flake) or Billfish (Broadbill, Swordfish and Marlin) and no other fish that fortnight
OR
1 serve per week of Orange Roughy (Deep Sea Perch) or Catfish and no other fish that week

 

4. Which fish have lower levels of mercury and can safely be included in my diet?

Fish that have much lower mercury levels and are also high in Omega 3 fatty acids include:

• Mackerel;
• Silver Warehou;
• Atlantic Salmon;
• Canned Salmon & canned tuna in oil;
• Herrings and
• Sardines

Other fish with low mercury levels include:

• All prawns, lobsters and bugs;
• All squids and octopus:
• Snapper;
• Salmon and trout;
• Trevally;
• Whiting;
• Herring, Anchovy;
• Bream;
• Mullet;
• Garfish.

These fish can be eaten more frequently – two to three times per week.

5. Should I avoid eating fish if I am breastfeeding?

No. The benefits of breastfeeding your baby far outweighs any risk posed by the insignificant amount of mercury that might be present in breast milk.

The critical time for the baby is while it is still developing in the womb. This is why scientifically-based diet advice recommends women start to limit their exposure to mercury to fish prior to pregnancy. This is no more difficult than reducing your weekly intake of certain types of fish, chiefly marlin, broadbill and shark. (see table)

By doing this you will reduce the amount of mercury in your body before getting pregnant. This means only insignificant amounts of mercury will be present in your breast milk – not enough to affect your or your baby.

Simply follow the same dietary advice as for pregnant women.

6. Should I be giving fish to my young children?

Yes. The healthy nutrients found in fish are excellent for growing children. Simply follow the advice in the table.

But remember, the Australian Dietary Guidelines recommend a variety of foods be consumed.

7. Is canned tuna and salmon safe to eat regularly?

Yes. It is generally safe for all population groups, including pregnant women, to consume two to three serves of any type of tuna or salmon a week – canned or fresh.

Canned tuna generally has lower mercury levels than other tuna because tuna used for canning are smaller species that are caught when they are less than one year old.

8. Does processing or cooking reduce mercury levels?

No. Mercury content is not reduced by processing techniques such as canning, freezing or cooking.

9. What if I eat more than 2-3 serves of fish per week?

Like all foods, fish should be eaten as part of a varied and balanced diet. Over-consumption of any single food group, particularly to the exclusion of other foods, is not recommended because it can lead to dietary imbalances and may increase your intake of potentially harmful substances, such as mercury.

If you do eat more than 2-3 serves of fish per week it is important you eat a variety of fish, and avoid those that could have elevated mercury levels, such as shark/flake, marlin and billfish. see table |

10. What if I had been eating more than 2-3 serves of fish in the past – how long before my mercury levels return to normal?

Providing you follow the recommended number of weekly portions, your mercury levels will return to normal fairly soon.

Mercury levels will generally halve within several months, providing you follow the dietary advice and limit the amount of shark/flake, marlin and billfish you consume.

If you are concerned about your mercury levels your doctor can advise you on simple tests that are available.

11. What about fish oil products?

Fish oil products and supplements are not a major source of dietary mercury and there is no recommendation to restrict consuming them because of mercury.

12. Is other seafood such as crustacea or molluscs a concern?

No. Crustacea (including prawns, lobster and crabs) and molluscs (including oysters and calamari) generally contain lower levels of mercury than finfish. Also, crustacea and molluscs tend not to be consumed as regularly, therefore they are not a concern.

NOTE: You should be aware some crustacea and molluscs can pose other health concerns for pregnant women – see the Food Authority’s fact sheets below for more information.