Your experiences are very valid. No one is saying otherwise. I just don't want people who could benefit greatly from low carb to be scared away from it by fear mongering that is not based on science.
His blog is slick and it is definitely "monetized" with his payed "programs" and supplements but, hey, I'm not going to knock him for that as our own beloved Mark does the same.
All that being what it is, the simple fact is that T3 production does go down in response to lowering carbs but this is normal and natural because less T3 is needed with a low carb diet. This lowering of T3 can (not does or will, but CAN) cause problems for someone who already has a thyroid disorder. Eating more carbs will not cure the thyroid problem but it may mask the symptoms for a while.
Bottom line, the thyroid is a very complex mechanism. I would rather trust mine to an endocrinologist than an acupuncturist.
I would like to second Paleobird's comment about 'fear mongering.' I am constantly reading posts from people who are eating low carb and having a positive experience but worried that it is somehow destroying their thyroid. That's based entirely on the type of misinformation that is promoted by people who have a little information but no real knowledge.
I find it incredible that people tend to believe Internet postings or blogs from people with no real credentials. Unfortunately, claims like Kresser's can sound reliable (low carb lowers T3)--but the uninformed reader doesn't know that 1) it's a natural bodily change because the higher T3 isn't necessary with low carb; 2) it is not a permanent change--in a healthy person, the thyroid hormones are self-regulating, depending on the needs of the person.
For example, researchers were astounded some years ago when they noticed that critically ill patients in hospitals who had no thyroid problems had VERY low T3 levels. They wondered whether this was impeding recovery. Further research showed that this was an activity of the body's immune system that was actually promoting healing (in ways that scientists still don't fully understand), and that T3 levels returned to normal once the individual had recovered from the illness.
Since I'm hypothyroid and regularly checked by my endo, I run some of these 'myths' that seem plausible by him, and he is aware of the nonsense on the Internet because, he tells me, patients are always asking him about things they read that 'scare' them but aren't true medically.
Disclaimer: I eat 'meat and vegetables' ala Primal, although I don't agree with the carb curve. I like Perfect Health Diet and WAPF Lactofermentation a lot.
Griff's cholesterol primer
5,000 Cal Fat <> 5,000 Cal Carbs
Winterbike: What I eat every day is what other people eat to treat themselves.
TQP: I find for me that nutrition is much more important than what I do in the gym.
bloodorchid is always right
There is an area that Chris Kresser studies called functional medicine. This does not make him an endocrinologist, but it does make him much more qualified to pontificate on complex biochemistry than your run of the mill acupuncturist. If you are interested in what this mode of health care is see here Institute for Functional Medicine > Home.
Last edited by Artbuc; 11-15-2012 at 04:49 PM.
The possible issue with VLC for some people does not impact the function of the thyroid. It can impact thyroid hormone conversion. Thyroidmanager.org* suggests that people need a minimum of 50 grams/day of glucose for good T4( storage hormone)to T3( active hormone) conversion. With this in mind, ingesting less than 50 grams of carbs/day long term MAY negatively impact conversion.
I recall reading somewhere (can't remember where) that an issue with VLC and conversion is person specific- not impacted at all, impacted quickly with VLC, impacted after long term VLC or something in between.
That being said, other things can impact conversion as well:
1. Not eating enough
2. Low selenium. 200mcg/day is needed
3. Low Vitamin D
4. Low ferritin
* Effects of the Environment, Chemicals and Drugs on Thyroid Function – Thyroid Disease Manager
scroll down to Nutrition
The Non-Thyroidal Illness Syndrome – Thyroid Disease Manager
scroll down to Low T3 states
My thoughts--If you are VLC and feeling/functioning fine/symptom free then VLC most likely isn't an issue for you. If, however, you are suffering from hypothyroid symptoms-- fatigue, cold intolerance, weight gain etc. I would make sure the things listed above are optimal. Then, if symptoms persist, I would look at diet- am I have eating enough calories and I'd experiment with increasing my carb level.
If after doing all that, symptoms still remain I think it's time for testing-- Thyroid( TSH, FT4, FT3, antibodies) Vitamin D, ferritin. Low T3 issues generally present with truly normal TSH, normal FT4 and low FT3.
I also do not think discussing VLC and it's possible impact on thyroid hormone conversion is fear mongering. I see it as educational. Each person is different. How we as individuals react to specific foods, macros, etc. is not "one size fits all". The more information we have the better choices we can make, helping us have the best life we can.