Low mercury seafood for pregnancy and breastfeeding

Seafood is a great food choice during pregnancy and breastfeeding, it’s packed with many beneficial nutrients! However, many women are worried about what seafood to eat and in particular about mercury in seafood. Here’s what you need to know.

Reasons to love seafood

it’s a great source of lean protein
it’s rich in key essential nutrients including iodine, iron, B12 and zinc which are all important for fertility and pregnancy
oily fish are also the best dietary source of omega 3 fatty acids which support fertility and infant development during pregnancy and breastfeeding

Recommendations for pregnant and breastfeeding women (and children up to 6 years old, too)

In Australia it is recommended that pregnant and breastfeeding women consume fish/seafood 2-3 times per week, especially because this is a great dietary source of iodine.

But, there are a few types of fish that shouldn’t be consumed so frequently, because of higher mercury levels in those types of fish. It is recommended that women limit their consumption of:

shark (flake), broadbill, marlin and swordfish - eat no more than once a fortnight and have no other fish during that fortnight; and
orange roughy and catfish - eat no more than once a week and have no other fish during that week.
And yep - these recommendations also apply to young children, up to the age of six.
(Source: NSW Health)

What’s the deal with mercury in fish?

Mercury occurs naturally in the environment. The flesh of fish/seafood accumulates some mercury in a form called methyl-mercury.

All fish and seafood contain some level of methyl-mercury. However, some species of fish contain more than most because they have a long life span (and so have more time to accumulate a higher level of mercury) and/or they are predator fish (and so accumulate more because they consume other fish).

Now, before you start to worry too much, most fish available in Australia contains low levels of mercury.

However, there are specific government health recommendations for (1) women who are trying to conceive, pregnant or breastfeeding and (2) children up to 6 years old. This is because too much mercury can potentially affect young, developing nervous systems and so these groups of people should exercise more caution.

What types of fish and seafood have lower mercury levels?

NSW Health provides the following list of fish and seafood.

Lower in mercury and high in omega 3 fatty acids:

Mackerel
Silver Warehou
Atlantic Salmon
Canned salmon and canned tuna in oil
Herrings
Sardines

Other seafood with lower mercury levels:

All prawns, lobsters and bugs
All squids and octopus
Snapper
Salmon and trout
Trevally
Whiting
Anchovy
Bream
Mullet
Garfish

Canned tuna vs. fresh tuna?

The reason canned tuna is lower is because the type of tuna that is used for canning is usually a smaller species and is caught when less than one year old. (Source: Food Standards Australia New Zealand)

Summary: mercury and fish for pregnancy and breastfeeding

If you are trying to conceive, pregnant and/or breastfeeding, eat fish/seafood 2 to 3 times per week.
Avoid shark (flake), broadbill, marlin, swordfish, orange roughy and catfish. If you have to eat one of these types or really want to eat one of these types:
- Shark (flake), broadbill, marlin, swordfish: allowed once a fortnight and then no other fish/seafood the rest of the fortnight.
- Orange roughy, catfish: allowed once a week and then no other fish/seafood the rest of the week.
Make sure you ask at restaurants and takeaway shops what type of fish they are using in your meal. Shark (flake) is commonly used in takeaway shops.
Serving size: one serve is 150 grams for adults (and 75 grams for young children).

Also, just a reminder which isn’t mercury-related. If you are pregnant, make sure you also avoid all raw fish, cold smoked fish (like smoked salmon) and ready-to-eat chilled peeled prawns. This is a food hygiene issue - these foods carry a higher risk of contamination!

Do you have any other questions about fish and seafood? Let me know!

Are you ready to plan a nutritious and balanced diet to support your fertility, pregnancy or postpartum journey? Get in touch and book a FREE 15 minute call so we can chat about how I can help you.