B12 and Thyroid disorders

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helvella
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by helvella on Thu Jan 19, 2012 10:20 pm

B12 and Thyroid disorders

It appears that the prevalence of B12 inadequacy in thyroid disorders is high. For example, I have read of a suggestion of 14% in idiopathic myxoedema. And that impaired absorption of B12 is widespread in many hypothyroid suffers. And even that it occurs in hyperthyroidism. And that parietal cell antibodies are frequently raised in autoimmune thyroid disease.

Why then, is testing for B12 not automatic when a thyroid blood test confirms hypo- or hyper-thyroidism?

After all, treatment is often inexpensive and simple (with high dose oral supplementation being all that is necessary in many cases).

Of course, folates should be tested alongside B12.

Further, the extraordinarily low value usually found to be the bottom of the reference range often appears grossly inadequate for many. And obtaining a second or subsequent test (whether B12 directly or methyl malonate, etc.) means that monitoring of treatment is effectively not done at all. And as for the possibility that the B12 level continues to decline after treatment starts, and even after an initial in-range test, well, that isn't even considered. And yet, given the large reservoir of B12 just that situation can and does seem to arise. Possibly years later. Hence not associated with the thyroid as that issue has already been dealt with.

Rod

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Professor John Lazarus
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by Professor John Lazarus on Wed Jan 25, 2012 10:41 am

Re: B12 and Thyroid disorders

Dear Rod
Most patients with hypothyroidism have normal levels of B12 and folate. About 10% of autoimmune hypothyroid patients have pernicious anaemia ( in my experience the number is less than that). The current parctice is to initially treat the hypothyroidism with T4. If B12 is low due to poor intake T4 will tend to correct the situation. If there is an inadequate response to T4parietal cell antibodies and B12 should certainly be measured. The cost effectiveness for screening all patients with autoimmune thyroiditis for parietal cell antibodies probably does not justify this strategy. Clinical vigilance during therapy of the hypothyroidism is the important aspect.

Yours sincerely
John Lazarus
Professor John Lazarus
Emeritus Professor of Clinical Endocrinology

shaws
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by shaws on Wed Jan 25, 2012 12:32 pm

Re: B12 and Thyroid disorders

Sir,

How do you know that most hypothyroid people have normal B12 and folate if it is not tested?

Shaws

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Professor John Lazarus
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by Professor John Lazarus on Thu Jan 26, 2012 4:30 pm

Re: B12 and Thyroid disorders

Because studies where 100% testing has been done have shown this
Professor John Lazarus
Emeritus Professor of Clinical Endocrinology

shaws
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by shaws on Thu Jan 26, 2012 5:15 pm

Re: B12 and Thyroid disorders

Thank you.

helvella
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by helvella on Thu Jan 26, 2012 9:53 pm

Re: B12 and Thyroid disorders

Thank you for your response, Professor.

I am convinced that in a considerable proportion of people, the B12 does indeed rise back once treatment commences.

One of the things I have noticed in communication with hypothyroid people is those who have relatively low B12 even after years of treatment (usually with thyroxine). Of course, this could be due to inadequate treatment. But maybe in some, the levels remain not too bad due to the large storage of B12 - and only slowly drop over years. Leaving the person with low B12 - but not quite bad enough to qualify as pernicious anaemia.

And the other group, those who are low on B12, possibly because they have had impaired absorption over many years of being mildly hypothyroid such that the reach their hypothyroid diagnosis with distinctly low B12. It certainly seems feasible to me that repletion of B12 might actually help with recovery.

By the way, there is clearly always some form of cost-benefit analysis, so how much does a B12 test cost (assuming blood draw at same time as other tests such as annual TSH)?

Or would it be pragmatic simply to advise purchase of suitable B12 supplements?

Rod

fennel
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by fennel on Fri Jan 27, 2012 12:47 pm

Re: B12 and Thyroid disorders

B12 is so cheap and not likely to cause any problems if it is supplemented even if it is not needed. I had a low figure and decided to supplement it myself and it is helpful for energy and clarity of thought. The uk range may be set a little low as I have heard that in Japan they have a normal range that goes up to 1000.

I also had a test for ferritin and as it was low in the 'normal' range I supplemented it, and my blue-ish lips got pinker and I felt better. I read on an arrhythmia forum that low ferritin can be one of the causes of arrhythmia and since I have got my levels up that has gone away.

I have worked hard to get better, why don't more patients put some effort into it instead of handing their body over for a doctor to take total responsibility for them? This is the paternal system that is encouraged. Surely a patient knows how they feel and nobody is better to judge their 'wellness' or otherwise. I really believe that the culture of patients being like children and accepting without question the treatment doled out is very convenient for the doctor, but it should be a partnership and we should have support to find our way to health in whatever way is acceptable to us, the patients. Please give your patients permission to own their own bodies.

If someone feels better by supplementing or dieting it doesn't matter that there is no research to back it up, perhaps the research should concentrate on the experience of patients if it is important to find out just how things work. But to me the important thing is that it does work and I don't mind not knowing why it works. It would be nice for other patients to know diet and supplements might help so that they can try it out too.

helvella
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by helvella on Fri Jan 27, 2012 6:31 pm

Re: B12 and Thyroid disorders

Fennel,

B12 is very cheap. And, many report, very safe for most people. But I would like to read Professor Lazarus' opinion as he might well have a different view.

And I feel the need to repeat a post I made the other day, somewhere else:

What units Fennel?

Broadly there are two units used around the world:

pg/mL (which is identical to ng/L)

AND

pmol/L

The ranges for these two units are similar, since the molecular weight of B12 is approximately 1000, which is also the difference between mL and L. Thus, for example, 550 pg/mL = 400 pmol/L.

Close enough easily to be confused. Different enough to cause confusion.

Rod

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