L-carnitine & cellular thyroid metabolism: Any conclusions?

[picante]

I'm starting this thread because I got a tad annoyed. Reading through threads on L-carnitine, I keep running across the statement that L-carnitine can keep thyroid hormones (T3, T4) from entering cells.

Most of the time there is no documentation given (thus the annoyance). The documentation that I have seen linked is to studies done on hyperthyroidism:
http://www.ncbi.nlm.nih.gov/pubmed/15591013 (a randomized clinical trial on iatrogenic hyperthryoidism!)
http://www.ncbi.nlm.nih.gov/m/pubmed/11502782/ (a clinical trial that looked at symptoms of hyperthyroid patients)
From the second link:

Old studies in animals and unblinded studies in a few hyperthyroid patients suggested that l-carnitine is a periferal antagonist of thyroid hormone action at least in some tissues. This conclusion was substantiated by our recent observation that carnitine inhibits thyroid hormone entry into the nucleus of hepatocytes, neurons, and fibroblasts.

I'm not at all sure this applies to those of us who are hypothyroid. My understanding is that hyperthyroidism causes urinary carnitine wasting, which would lead to deficiency, ¿no?

I've just gone in circles trying to get a bearing on this:
Here on PR we have hypothyroid people doing the deadlock quartet who say they have had improvement and had to lower their thyroid dosage. This makes sense: glutathione is needed for the conversion of T4 to T3 (http://metabolichealing.com/thyroid-solutions-glutathione-t4-t3-conversion/), and methylation protocols can increase glutathione levels.

I'm not sure it works to look at L-carnitine in isolation, in other words.

So I'm tracking my own responses to ALCar now, which is the form I've been taking lately. I'm recording my temperatures and my perception of fatigue. FYI, I'm taking a compounded T3/T4 sublingual for a combination of thyroid problems: low T4-to-T3 conversion and TPO antibodies.

So far, I'm not seeing any discernible difference in my body temperatures in the 30-60 minutes after taking ALCar. However, I usually take AdoB12 within 30-60 minutes of the ALCar. Once I take the AdoB12, I am seeing a temperature increase. I've been recording them for 5 days, and getting between .2 and .6 degrees Fahrenheit increase in 20-30 minutes after taking AdoB12.

I'm not seeing any particular pattern yet with fatigue. Fatigue seems to be more affected by eating, in my case.

Those who have posted before on L-carnitine & hypothyroidism, have you found any more clues or research?: @Sea @ahmo @SOC @South @Gondwanaland @caledonia @Freddd

 

[Martial]

From what I have read before on it, in the amounts of supplemented form it is negligible. Especially if you take it only once a day because of the short half life. Certain foods actually have just the same effect, and others boost thyroid hormone.

 

[dannybex]

@picante This has been driving me crazy as well.

First of all, different docs have different views on how to determine thyroid status. My medicaid MD says my thyroid is fine, while the naturopath I saw said my thyroid had been slowing down dramatically over the last 10 years and prescribed Nature-Throid a few years ago. Stupid me, I never took it on a regular basis, and now the doc has moved back east.

I used to take l-carnitine regularly up until about 7-8 years ago, and found it helped considerably. It lowers lactate and is necessary for PDH function, etc. Then I stopped when I read it could 'tank' one's choline levels. In hindsight this was no doubt a mistake, after all it came from a comment w/nothing to back it up, but I was going through a panicky time after starting on methylation supps, and was grasping at straws.

Anyway, it seems like whenever I've tried it recently, I get really cold feet, which already have a tendency to be cold. On the other hand, sometimes my feet get icy cold and I haven't taken any carnitine.

Then I came across this study, which seems to suggest a self-regulating mechanism is involved -- carnitine excretion is increased in hyperthyroid patients, but reduced in hypothyroid.

Am I reading that correctly?

 

[picante]

Then I came across this study, which seems to suggest a self-regulating mechanism is involved -- carnitine excretion is increased in hyperthyroid patients, but reduced in hypothyroid.

Am I reading that correctly?

I think so. Of course, I had forgotten all about my post above, and so I'm glad you tagged me. I'm still hypothyroid -- in fact, more than ever, since I haven't been tolerating thyroid hormones of any kind. That, I found out, was because my cortisol plunged over a year ago.

AFAIK, I've been hypothyroid for 25 years, since EBV meningitis triggered my onset of ME/CFS. And that whole time, my triglycerides have been around 90 -- pretty low, in other words. I don't know that supplemental thyroid ever lowered my triglycerides, as this study seems to say.

Are your triglycerides low? I take it you aren't on any thyroid meds now?

 

[Gondwanaland]

my triglycerides have been around 90 -- pretty low

This is normal on a GF diet.

 

[picante]

This is normal on a GF diet.

I wasn't avoiding wheat until later in that 25 years. But do you think 90 is a normal level? I don't know much abour triglycerides.

 

[picante]

It lowers lactate and is necessary for PDH function, etc.

What is PDH?

 

[Gondwanaland]

I wasn't avoiding wheat until later in that 25 years. But do you think 90 is a normal level? I don't know much abour triglycerides.

The desirable level is between 50 - 90

 

[dannybex]

Are your triglycerides low? I take it you aren't on any thyroid meds now?

No, they're high, and have been gradually moving higher for about 4-5 years. I had no idea of the thyroid connection until I saw this study. And am not on any thyroid meds right now. I have read as you have that there's a balance between it and the adrenals, so plan on taking some adrenal extract at the same time. Vitacost has one that actually helps me w/the 'wired but tired' thing.

 

[dannybex]

What is PDH?

It stands for the pyruvate dehydrogenase complex, which has been mentioned in at least one or two of the recent studies. Carnitine is just one of many 'ingredients' that goes into helping it function normally/correctly.

https://en.wikipedia.org/wiki/Pyruvate_dehydrogenase_complex

 

[Critterina]

@dannybex ,

I don't really see your problem with the studies you cite. They show that taking L-carnitine reduces effective thyroid. They show it in hyperthyroid situations, probably because it would be irresponsible to lower thyroid in hypothyroid situations. Clinically, it is used to treat hyperthyroid. (Ask your endocrinologist.) The amount that is used is in the same order of magnitude as the supplements, (OOM 1 g), tailored to the individual's response.

The feedback mechanism you cite is not self-regulating; what they point out is a correlation. In fact, if hyperthyroid causes increased carnitine elimination, then it is an exacerbating effect. They make a suggestion about cause and effect, but unless you have more than the abstract, you can't really tell what the data says.

Therefore, without medical supervision, it would not be advisable for hypothyroid people to use L-carnitine, probably even in the 500 mg range.

Now, why people on this forum report improvement may be tied to the fact that almost no one is only using one supplement. Which ones have the most impact may depend on what's most broken in their chemistry.

 

[dannybex]

@dannybex

Therefore, without medical supervision, it would not be advisable for hypothyroid people to use L-carnitine, probably even in the 500 mg range.

Now, why people on this forum report improvement may be tied to the fact that almost no one is only using one supplement. Which ones have the most impact may depend on what's most broken in their chemistry.

I agree. I guess my main point was exactly that, that if one is hypothyroid, then they should treat w/thyroid (or try to find out or figure out what's behind the hypo-t) before adding l-carnitine. Like I said, I never used to have a problem with it, and also wasn't losing muscle when I was taking it. One of the key reasons I want to start it again is because it lowers 3-methylhistidine, the marker for muscle breakdown.

 

[Critterina]

I agree. I guess my main point was exactly that, that if one is hypothyroid, then they should treat w/thyroid (or try to find out or figure out what's behind the hypo-t) before adding l-carnitine. Like I said, I never used to have a problem with it, and also wasn't losing muscle when I was taking it. One of the key reasons I want to start it again is because it lowers 3-methylhistidine, the marker for muscle breakdown.

Not saying this is good for anybody but me, but when I had high 3-methylhistidine, I was prescribed BCAAs. Maybe digestive enzymes also, so that I would be digesting my dietary protein better. The thought was that I wouldn't be breaking down my muscles if I got enough protein absorbed from my diet (which had plenty, I just wasn't absorbing it.)

Edit because I just remembered: I had been having extreme, deep aches in my thighs. It almost felt like bone pain. No stretching or positioning did anything, and I had a lesion in my femur on an x-ray, and it really hurt only when I laid down at night. (Thus I was afraid I had bone cancer and pursued diagnosis with an osteooncologist.) No pain while I was standing. None when I got up in the morning. The day I started the BCAAs, the pain disappeared, but I started a lot of things that day. I ran out of the BCAAs 12 days later. The pain appeared on Day 13. I emailed my practitioner to see if I was supposed to take more than the one bottle, but it went to her spam. I waited about 6-7 days and decided that I was going to keep taking it. That very day, the pain stopped again. Weird, huh?

 

[dannybex]

That is weird @Critterina, but perhaps your muscle was being broken down at such high rate, the BCAAs helped slow down or stop that so that it could/can support your hip better?

Did you ever have another 3-methylhistidine test to confirm it had normalized?

 

[Critterina]

That is weird @Critterina, but perhaps your muscle was being broken down at such high rate, the BCAAs helped slow down or stop that so that it could/can support your hip better?

Did you ever have another 3-methylhistidine test to confirm it had normalized?

I think you're right. I lost about 27 lbs and much muscle bulk just before treatment. I think it had something to do with that. It wasn't actually my hip that hurt, but the femur, from knee to hip, front side. I did stop losing weight. In 3 months I had gained 4 lbs, 100% muscle per the body composition testing.

Yes, I have had several amino acid panels since and the 3-methyl histidine got in line right away, which was spring 2013. (And everything else, thank God, was still normal on my last test). It's been a while, but I like saying that, and my doctor doesn't do that test unless I ask for it.

My digestion has improved (majorly starting Dec 2014) and I've not been taking the BCAAs for a long time. I did have the symptom recur, and I did a week or so of the BCAAs (immediate relief) and additional probiotic/gut rebuilding, and haven't had the trouble.

 

[dannybex]

That's very encouraging @Critterina -- thanks for your reply.

Here's a study that showed that BCAAs are used during exercise:

https://www.ncbi.nlm.nih.gov/pubmed/15173434

And this one was interesting as they concluded that "The mechanism could be attributed to the availability of ammonia provided by the oxidation of supplemented BCAAs during exercise."

I've always looked at ammonia as a negative. I mean it's a normal process in the body, but still don't understand what they're suggesting, as other amino acids/protein produce ammonia as well...

 

[Gondwanaland]

@dannybex I noticed worsening of symptoms since using leucine as excipient in some of my supplements. I found out it was causing problems with the Tryptophan metabolism, and adding B2 + Biotin to B6 helped since they are needed to "clear the way" for proper Niacin and serotonin synthesis from Trp. B5 is also needed to activate Melatonin.

 

[Critterina]

@dannybex

Test results in 2013:

Obviously, we overshot with the supplements. BCAAs were started in February.