Is tuna safe to eat while breastfeeding? (3+ risks)

In this article, we will discuss whether tuna is safe to eat while breastfeeding, the risks of eating tuna while breastfeeding, if there are benefits of eating tuna while breastfeeding and what are the alternatives to tuna while breastfeeding. 

Tuna is known to be a very nutritious fish and is widely consumed due to its flavour. However, eating tuna is not recommended during pregnancy and while breastfeeding.

Is tuna safe to eat while breastfeeding?

No, tuna is not safe to eat while breastfeeding. Tuna is considered an unsafe fish during pregnancy and while breastfeeding in many countries by their Food Safety Authorities due to high levels of heavy metal contamination, especially mercury (1).

The recommendation of not eating high-mercury fish is emphasised only during pregnancy in some countries, while it continues also while breastfeeding in others, including in the United States, Canada, Finland, France and Denmark.

Why is it not safe to eat tuna while breastfeeding?

It is not safe to eat tuna while breastfeeding due to the generally high levels of mercury and other heavy metals in the fish, which may be harmful to the unborn child or the baby (1, 2).

Heavy metals may impair the child´s brain development, cause permanent brain damage, and may cause infertility, damage to the kidney and the bones and lead to different types of cancer (1, 2, 3).

Can the breast milk contain mercury?

Yes, breast milk can contain mercury if the mother consumes foods that contain mercury. However, how much of the mercury will be absorbed by the baby depends on its chemical form.

For instance, methylmercury passes in a low quantity through the breastmilk and is highly assimilated by the baby, while inorganic mercury passes rapidly through the breastmilk but is not easily absorbed by the baby (2).

Therefore, although there is plenty of evidence that heavy metals are transported through the placenta to the unborn during pregnancy, and are well reported, the same is not for the transport of heavy metals through breastmilk (2).

How and to which extent the ingested heavy metals become available and assimilated by the baby is not yet understood.

How much tuna can you eat while breastfeeding?

It is wiser to avoid possible risks and follow the medical recommendation (1). It is recommended to eat fresh tuna or canned tuna once every two weeks when pregnant and while breastfeeding (1).

Is canned tuna safe while breastfeeding?

No, canned tuna is not safe while breastfeeding. According to studies, commercially available canned tuna contained a high level of mercury, lead and cadmium in samples of canned tuna in Brazil, Spain, Turkey, and Italy (3, 4).

Tuna is a large predator fish at the end of the food chain and therefore accumulates heavy metals by eating smaller fish (1, 3, 4).

What are the benefits of eating tuna while breastfeeding? 

The benefits of eating tuna while breastfeeding are the omega-3 polyunsaturated fatty acids, the proteins and the minerals in tuna, which makes it an important food source for the human diet. 

The ingestion of omega-3 fatty acids during pregnancy and breastfeeding favours the neurological development of the fetus and the baby. Tuna also contains selenium, vitamin D and iodine (1).

The insufficient ingestion of omega-3 fatty acids or the neurodevelopment vital nutrients during pregnancy and breastfeeding can lead to a lower intelligence quotient (IQ) of the child (1).

What are possible alternatives to tuna while breastfeeding?

Possible alternatives to tuna while breastfeeding are anchovy, mackerel, herring and sardine. All fish mentioned are also rich in nutrients and are sources of omega-3 fatty acids (1).

They are considered safe by the Governmental Agencies regarding their levels of heavy metals (1).


In this article, we discussed the safety of eating tuna while breastfeeding, why should you not eat tuna while breastfeeding, what are the benefits of eating tuna and what are possible alternatives to tuna while breastfeeding.

Tuna is widely consumed in Japanese cuisine due to its colour, flavour and nutritiousness. I recommend eating tuna in moderation, but not when pregnant and while breastfeeding. One can survive without tuna for a few years!

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Taylor CM, Emmett PM, Emond AM, Golding J. A review of guidance on fish consumption in pregnancy: is it fit for purpose?. Public health nutrition. 2018 Aug;21(11):2149-59.


Gundacker C, Zödl B. Heavy metals in breast milk: Implications for toxicity. Reviews in food and nutrition toxicity. 2005 Mar 17;4:1-28.


Pappalardo AM, Copat C, Ferrito V, Grasso A, Ferrante M. Heavy metal content and molecular species identification in canned tuna: Insights into human food safety. Molecular Medicine Reports. 2017 May 1;15(5):3430-7.


de Paiva EL, Morgano MA, Milani RF. Cadmium, lead, tin, total mercury, and methylmercury in canned tuna commercialised in São Paulo, Brazil. Food Additives & Contaminants: Part B. 2017 Jul 3;10(3):185-91.