3

votes

Are PUFAs and muscle meat bad for the thyroid?

Answered on August 19, 2014
Created April 09, 2013 at 9:36 PM

I hear this all the time, especially from Peat followers but I can't find anything conclusive.

A2c38be4c54c91a15071f82f14cac0b3

(12682)

on April 12, 2013
at 03:38 AM

Your link doesn't work for me (it sends me to some weird video site) but I looked for that post on Stephan's blog and he apparently removed that post saying "I think the idea that linoleic acid (the main fatty acid in most seed oils) interferes with thyroid function in a significant way is on shaky ground" (seen here: http://wholehealthsource.blogspot.com/2011/08/seed-oils-and-body-fatness-problematic.html)

4bd4e2fe6a095663f80c69656936e487

(744)

on April 11, 2013
at 11:10 PM

Blog: Omega-6 Linoleic Acid Suppresses Thyroid Signaling. http://wholehealthsourcee.blogspot.com/2008/12/omega-6-linoleic-acid-suppresses.html

4bd4e2fe6a095663f80c69656936e487

(744)

on April 10, 2013
at 02:38 AM

Who would benefit from funding such study? If it had a positive effect on thyroid, I think the seed-oil industry would've funded it.

A2c38be4c54c91a15071f82f14cac0b3

(12682)

on April 10, 2013
at 02:20 AM

It's funny how little I can find on this issue in humans. Effect of PUFA's on cholesterol levels? Boom, 8 billions studies. Effect on thyroid hormones? I couldn't find any in 20 minutes of searching. Bahh.

A2c38be4c54c91a15071f82f14cac0b3

(12682)

on April 10, 2013
at 02:15 AM

Hah yeah I went looking for it after our last discussion about this.

4bd4e2fe6a095663f80c69656936e487

(744)

on April 10, 2013
at 01:50 AM

Thanks for that Burr link you posted by the way.

4bd4e2fe6a095663f80c69656936e487

(744)

on April 10, 2013
at 01:47 AM

I wouldn't call the evidence "definitive" based on these studies either, but they were enough to make me want to try it, and I felt a lot better.

A2c38be4c54c91a15071f82f14cac0b3

(12682)

on April 10, 2013
at 12:59 AM

Here's that study btw: http://jn.nutrition.org/content/16/6/511.full.pdf

4bd4e2fe6a095663f80c69656936e487

(744)

on April 09, 2013
at 11:44 PM

Yes, on rats. That one individual was the only human I heard about. But it was 1 person.

742ff8ba4ff55e84593ede14ac1c3cab

(3536)

on April 09, 2013
at 11:21 PM

Thanks I'll look into them. Are most studies of this kind done on animals?

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3 Answers

3
A2c38be4c54c91a15071f82f14cac0b3

(12682)

on April 10, 2013
at 12:59 AM

On this question I pointed out that meat doesn't seem to lower thyroid function:

http://paleohacks.com/questions/171996/why-does-eating-meat-increase-iodine-requirements#axzz2Q0gKCRw1

As far as PUFA's I think there's not much evidence that omega-3's will adversely affect thyroid function if you look at chickens (1) or rats (2). Nor do they negatively affect metabolic rate in humans (3).

Like yourself I would quite like to know whether omega-6's adversely affect long thyroid levels or long term metabolic rate. I've seen evidence that they might (including the ones discussed by anon above), but nothing I would call definitive. I guess I would like to see a controlled study on humans.

4bd4e2fe6a095663f80c69656936e487

(744)

on April 10, 2013
at 01:47 AM

I wouldn't call the evidence "definitive" based on these studies either, but they were enough to make me want to try it, and I felt a lot better.

A2c38be4c54c91a15071f82f14cac0b3

(12682)

on April 10, 2013
at 02:15 AM

Hah yeah I went looking for it after our last discussion about this.

A2c38be4c54c91a15071f82f14cac0b3

(12682)

on April 10, 2013
at 02:20 AM

It's funny how little I can find on this issue in humans. Effect of PUFA's on cholesterol levels? Boom, 8 billions studies. Effect on thyroid hormones? I couldn't find any in 20 minutes of searching. Bahh.

4bd4e2fe6a095663f80c69656936e487

(744)

on April 10, 2013
at 01:50 AM

Thanks for that Burr link you posted by the way.

A2c38be4c54c91a15071f82f14cac0b3

(12682)

on April 12, 2013
at 03:38 AM

Your link doesn't work for me (it sends me to some weird video site) but I looked for that post on Stephan's blog and he apparently removed that post saying "I think the idea that linoleic acid (the main fatty acid in most seed oils) interferes with thyroid function in a significant way is on shaky ground" (seen here: http://wholehealthsource.blogspot.com/2011/08/seed-oils-and-body-fatness-problematic.html)

4bd4e2fe6a095663f80c69656936e487

(744)

on April 10, 2013
at 02:38 AM

Who would benefit from funding such study? If it had a positive effect on thyroid, I think the seed-oil industry would've funded it.

4bd4e2fe6a095663f80c69656936e487

(744)

on April 11, 2013
at 11:10 PM

Blog: Omega-6 Linoleic Acid Suppresses Thyroid Signaling. http://wholehealthsourcee.blogspot.com/2008/12/omega-6-linoleic-acid-suppresses.html

3
4bd4e2fe6a095663f80c69656936e487

(744)

on April 09, 2013
at 10:32 PM

"I can't find anything conclusive."

OK. This is what happened in some studies that have been done:

They gave PUFA to some rats, saturated fats to others. Measured their metabolism. It turned out that the rats that consumed PUFAs had slower metabolism.

Same thing with pigs. The pigs who ate PUFA got fat. Those who ate coconut oil lost weight.

Burr believed some PUFA were essential for rats. A student wanted to show that they were essential for humans too, so he ate a diet extremely low in PUFA for 6 months. The result, surprisingly, was that it didn't create any health problems. And they measured his metabolism, too! It was a faster metabolism than when he started.

You can find these studies easily if you use google, the Ray Peat forum, or Ray Peat's articles on PUFA. I saw the studies but I'm not going to find them for you.

A2c38be4c54c91a15071f82f14cac0b3

(12682)

on April 10, 2013
at 12:59 AM

Here's that study btw: http://jn.nutrition.org/content/16/6/511.full.pdf

4bd4e2fe6a095663f80c69656936e487

(744)

on April 09, 2013
at 11:44 PM

Yes, on rats. That one individual was the only human I heard about. But it was 1 person.

742ff8ba4ff55e84593ede14ac1c3cab

(3536)

on April 09, 2013
at 11:21 PM

Thanks I'll look into them. Are most studies of this kind done on animals?

1
4bd4e2fe6a095663f80c69656936e487

(744)

on April 10, 2013
at 01:41 AM

Here is a study that EFA deficiency (which requires low PUFA) accelerates metabolism in rats.

http://jn.nutrition.org/content/114/2/255.full.pdf

The rats however do have some problems. Ray Peat would attribute these problems to not providing the nutrients that a faster metabolism needs.

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