Should You Avoid Fish While Pregnant if You Have Thyroid Autoimmunity

Should you avoid fish while pregnant if you have thyroid autoimmunity? Thyroid autoimmunity can start or worsen during pregnancy. Because of this, avoiding fish is sometimes suggested because fish contains mercury, which may stimulate thyroid autoimmunity. But eating fish may actually protect against thyroid autoimmunity.

Have thyroid autoimmunity and need help deciding if eating fish is right for you? Click here.

If you have Hashimoto’s, thyroid autoimmunity, should you avoid fish consumption during pregnancy?

Dr. Michael Ruscio: Hi. This is Dr. Ruscio. And let’s discuss this question. Now, how does pregnancy relate to thyroid autoimmunity? In case you haven’t heard this before, during pregnancy, thyroid autoimmunity can worsen or it can initiate because of the oscillation of the immune system that occurs during pregnancy. So pregnancy is a high-risk time for thyroid autoimmunity.

Now, the issue of fish consumption comes up because fish contains mercury. And there is discussion that mercury may stimulate thyroid autoimmunity. So some have asked the question or made the caution that perhaps we should avoid fish consumption, because fish contains mercury, during pregnancy so as not to provoke a risky time where thyroid autoimmunity could worsen or could start.

A recent study Trusted SourcePubMedGo to source looked at this issue. And the researchers found something very interesting and very applicable in day-to-day life. And I’ll put the abstract up here on the screen with some notes. They found that common oily fish actually prevented or decreased the incidence of thyroid antibodies or thyroid autoimmunity.

So the more oily fish these women ate, the less thyroid autoimmunity they had. And the oily fish they tracked in this study were salmon, mackerel, sardines, trout, and herring. All those fish were protective against thyroid autoimmunity.

However, they noticed for swordfish there was an increased incidence of autoimmunity. So the more swordfish that was eaten, the more autoimmunity there was.

This may come back to something known as the mercury-selenium ratio. There are certain fish that will bioaccumulate more mercury and may have less selenium and therefore be more risky for thyroid autoimmunity. The common oily fish listed in this study are a safe bet because they will have less mercury and/or more selenium that will protect against the mercury.

So if you’re a mother and you’re concerned about thyroid autoimmunity, I would not recommend avoiding common oily fish as we’ve just gone through, because they can help with prevention of thyroid autoimmunity. And possibly more importantly, other studies have shown that consumption of fish translates to a higher I.Q. in the offspring. So of course, that’s something that we want to be very mindful of as well.

So again, pregnancy is a high-risk time for thyroid autoimmunity to get worse or to begin. Mercury may make thyroid autoimmunity worse. Fish contains mercury. But not all fish are the same in this regard.

Common oily fish like salmon, mackerel, sardines, trout, and herring, as this study found, are protective whereas other fish, like swordfish—and we could also put in that category whale, although I’m sure not many people are eating whale, but in certain Asian cultures whale is eaten—are mercury bioaccumulators, have a lot of mercury, and/or have less selenium. They’re more risky.

So during pregnancy, I would eat fish, but eat the right type of fish that can help decrease your thyroid autoimmunity and have a positive impact on the I.Q. of your child.

This is Dr. Ruscio. And I hope this information helps you get healthy and get back to your life. Thanks!

Have thyroid autoimmunity and need help deciding if eating fish is right for you? Click here.

What do you think? I would like to hear your thoughts or experience with this.


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