Posted by kathryn in A Balanced Diet, Kid's nutrition and Q & A Thursday

Claire has asked a question about mercury and tinned tuna:

We eat a lot of tinned tuna in our family, maybe once or twice a week, sometimes more. We use Serina tuna in oil mostly, and I have concerns about the mercury content of such a product . . . should we be avoiding tinned tuna?

Claire thanks for your question and the short answer is, no, you don’t have to worry about mercury in tinned tuna.

Mercury in fish

Mercury occurs naturally in our environment, so it’s impossible to completely avoid. However at high levels it’s pretty toxic and can interfere with the development of the central nervous system in unborn babies and young children. You’re right to be careful, although the critical time, when you need to be most aware, is while the baby is developing in the uterus.

Mercury accumulates in the environment, so the further the fish is up the food chain, the higher it’s mercury content.

Tuna

While a full-grown tuna is a large fish and high up the food chain, the ones that go into tins are generally less than one year old. They haven’t had time to accumulate high mercury levels and are safe to eat while pregnant and breastfeeding. I would limit tuna steaks and sushi though.

Should you still be eating fish?

While there is a concern about the mercury levels in fish, the benefits from eating fish during pregnancy, while breastfeeding and while kids are little, far, far outweigh the dangers.

Fish is a low fat source of protein. It’s high in zinc, B12 and iodine, plus some fish contain the lovely Omega 3 essential fatty acids. This latter group actually HELP neurological development and there have been a number of studies showing kids that have Omega 3s in their diet, have fewer behavioural problems, better concentration and do better at school.

There’s some really good information about mercury and fish on the NSW Food Authority website, including a list of the fish with low mercury levels , the fish to be careful of and whether cooking affects the mercury levels .

31 May, 2007