In many countries, including the US, Canada, the UK, and Australia, pregnant women are advised to limit certain types of fish during their pregnancy.
And while most pregnancy and health websites offer guidance on how much tuna is safe to consume while pregnant, they often leave out another important time in a mother’s life – breastfeeding and/or pumping her milk for the baby.
Stocked with choline, iron, and healthy DHA fats to support your baby’s brain development, tuna can be a wonderful addition to your diet during lactation. Choosing lower-mercury options such as canned light and skipjack tuna can help you meet the recommendation to eat fish 2-3 times weekly.
Though it sure would be convenient, the majority of commercially available tuna doesn’t come labeled with its mercury content.
In this article, I’ll break down exactly how much mercury is in each type of tuna, as well as provide guidelines for how often they can be eaten so you can eat with confidence knowing you’re getting more of the good stuff with less mercury.
Can I Eat Tuna When Breastfeeding?
Tuna is notoriously talked about during pregnancy because it contains mercury. All fish, including tuna, contain some mercury that comes from the water they are found in. Since tuna is typically a larger-sized fish its mercury content will be higher than smaller-sized fish.
Just like during pregnancy, women who are providing their milk for their baby (either by breastfeeding and/or pumping) are advised to limit their servings of high-mercury fish. The mercury in fish can pass from mother to baby in her breastmilk. In large amounts, mercury can affect the development of a baby’s brain and nervous system (source: FDA).
All of that is not to knock fish! Fish, including tuna, is a good source of protein, iron, choline, and DHA to support brain development. In fact, breastfeeding mothers are encouraged to continue eating 2-3 servings of fish each week for this very reason (source: FDA, NSW Food Authority).
Not all types of tuna are created equal, however. Some versions of this fish are higher in mercury and should be eaten more sparingly. The US Food and Drug Administration has categorized fish into 3 categories-
- Best choices, to eat 2-3 servings per week
- Good choices, as your 1 serving of fish in a week
- and choices to avoid, or eat only sparingly due to their higher mercury content
Below is a table of the average mercury concentration (given in parts per million, or PPM) in commercially caught tuna species:
|Canned light tuna
|Safe Catch brand tuna
|Yellowfin, also known as Ahi
Choices to Avoid/Limit
In some local areas, you may be able to purchase locally caught tuna or enjoy tuna caught by friends or family. In these cases, it is always best to check for any open fish advisories here.
Some areas may know they have high levels of mercury in their waters, and place an advisory letting folks know how much local fish is safe.
For example, my home state of Wisconsin has a special section on their natural resources website which lists all of the fish species in local waters and how often pregnant and breastfeeding mothers may eat them (source: Wisconsin DNR).
If there is no advisory, eat only 1 serving and make it your only serving of fish for the week (source: FDA).
Note that Safe Catch is a brand of tuna and other fish that tests each fish to ensure they know exactly how much mercury is in their products. The company has also set a lower threshold for how much mercury they allow- meaning their products are lower in mercury than other brands.
How Much Tuna Can I Eat When Breastfeeding?
Whether pregnant or breastfeeding/pumping, the amount of tuna that is safe to eat each week depends on the type of tuna you buy.
Canned light tuna, skipjack, and Safe Catch brand are all safe to eat 2-3 servings weekly. Albacore and yellowfin/ahi tuna have a bit more mercury and are recommended to eat no more than once weekly. The same goes for locally-caught tuna so long as there is no fish advisory in the area.
But what counts as a serving?
A single serving of tuna, regardless of the kind, is approximately 4 ounces (or 115 grams). For most women this is equal to about the size of your palm.
Can I Eat Raw or Spicy Tuna When Breastfeeding? e.g. Sushi?
After 9 (or maybe more) months of avoiding poke, sushi, and other forms of raw tuna many women wonder if their breastfeeding journey extends this timeframe or if they are safe to get back to their normal eating habits.
After you’ve given birth, your immune system will begin to build back up, meaning food safety is less of a concern- though always a smart idea to make sure you’re eating high-quality, sushi-grade tuna that has been prepared with safe food handling practices to avoid getting sick.
Raw and spicy tuna are no longer off the table, though if you’re breastfeeding it is important to opt for lower mercury species of tuna when possible.
Sushi, sashimi, poke, and tuna steaks can be made with a variety of tuna. The most common are bluefin, bigeye, yellowfin, and albacore. While yellowfin tuna and albacore have lower levels of mercury and are listed as ‘good choices’ by the FDA, bluefin and bigeye species tend to be quite high in mercury and are best limited.
Don’t be afraid to ask your server or butcher what species the fish came from, as most reputable establishments will either know or be able to easily find out for you.
When it comes to selecting a tuna steak, remember that larger fish will likely have higher mercury levels. If possible, select the steak that looks like it came from the smaller fish.
Much like in pregnancy, the health benefits of eating tuna may outweigh any risk of eating too much mercury. Following this guide can also help you choose the lower mercury option so you feel confident enjoying tuna and passing all of its brain-boosting benefits to your baby.
For more information on tuna in pregnancy, check out our updated guide to tuna while pregnant.