The Effects of Vitamin D Supplementation on Thyroid Function in Hypothyroid Patients: A Randomized, Double-blind, Placebo-controlled Trial
ncbi.nlm.nih.gov/pmc/articl...
I'm not really qualified to comment on this, but perhaps I can impose on diogenes to read this? It appears to suggest that taking Vitamin D improves/lowers TSH, but does not affect T3/T4. Any thoughts?
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It would seem to suggest that either vitamin D deficiency inhibits thyroid hormone action a little or vitamin D enhances this action a little. The effect was small and it's possible the study captured the change in TSH which is a more sensitive marker but didn't have the power to detect small changes in T3 or T4.
Regardless vitamin D is often low in hypothyroidism and there are many reasons to keep your levels up.
There is a potential significance in that if VitD can affect tsh without any direct or indirect^ affect (via the effect on tsh) then it may cause some confounding of judgemental decisions about thyroid status and the adequacy of thyroid hormone replacement. And if vitd has no sig effect on t3 or t4 then we should question the perception and belief that hypothyroidism requires vitd supplements for optimal management? This question notwithstanding that vitd supplement may be beneficial for many other reasons. My experience of vitd supplementation is that it makes no difference to my thyroid functions. VitD may be a red herring if there is concern about not doing well enough on replacement therapy which distracts from more urgent considerations of manipulating thyroid hormone replacement levels and timing of doses. Perhaps we clutch at anything we can do that is fully in our control with the erroneous influence or restrictions of prescribing physicians because the most profound and powerful effects come from the thyroid hormones themselves which are vastly more consequential than fiddling around with any of the alleged co-factors which could well be utterly insignificant in the face of suboptimal thyroid hormone status. In other words unless we are profoundly malnourished or proven to be chronically short of a micronutrient we should forget about everything except optimising thyroid hormone replacement.....
Oh snap. You said it better.
I totally agree. Once I started on NDT my health dramatically improved and as I titrated up I felt more and more like my old self until I felt completely better. My depression of decades completely vanished. I sometimes think fiddling about with vitamin pills is not the fundamental action required but as you say getting your thyroid hormones bang on is, many underlying imbalances will automatically be rectified in due course. .
Yes, or whatever the problem is. Now, I should also say that I live in a sunny country and eat animal foods. It may be that there really are people who don't get enough in the first instance.
Oh absolutely. I realise vitD deficiency exists for a variety of reasons and thyroid disorder is not going to be the cause in every case.
Very interesting, thanks for sharing.
Yes, the results are exactly as you thought, although not a huge effect on TSH levels. Every little helps though 
Vitamin D is actually a steroid hormone rather than a vitamin so it makes some sense that it may interact with the pituitary/thyroid.
I'm not sure that it helps at all. If it doesn't improve thyroid hormones I'm inclined to think it's not good if it lowers tsh, since so much reliance is put on tsh.
Good point that vitD is much more than a vitamin in the usual sense. I was given it for deficiency and severe depression but NDT was much more effective in correcting my mood state and has continued to be effective after 5 years of taking it. VitD tablets gave me severe cramp so I stopped taking them. I still get attacks now and again but it was every night on vitD3. I was told on here it could be provoking a magnesium imbalance
So what if you don't have a thyroid? I know I feel so much better with Vitamin D topped up but if it affects my TSH levels it is tiny.
Your TSH level no longer means anything if you have no thyroid function. It is free. T3 that matters
All I know is that I have no thyroid function at all (was born with only a non working partial gland). So have been supplemented with medication all my life. Everything was fine growing up. "but" they did have to lower my dose as a child, as at the age of five, I had the bone age of a seven year old!
After that, I had no problems until I was in my 30's thanks to my previous GP. Many moons later, I am back on my original dose of meds, plus T3, I now have got Pernicious anaemia, B12 deficiency and vitamin D deficiency diagnosed at the same time as the Pernicious anaemia. I have been on supplements and jabs as well as thyroid meds for fifteen years or more, (lost count).
Never had any problems with my bones, except for a small fracture on my little toe, when I had an argument with a door! 
In 2016 Bone density scan revealed that everything was fine and dandy.
So I go by the mantra, if you need supplementing, then supplement it. If it stops you getting diseases and gives you quality of life, then it is a good thing. At the end of the day, I think we would all agree that the TSH test is not accurate in most cases.
I think there is a lot of confusion over essential hormones and vitamins in our society these days.
Be safe and take care everyone
I sent a copy of this article to my doctor along with the argument that perhaps my Vitamin D supplementation was a plausible explanation for my low TSH and therefore I did not need my thyroid medication reduced.
Did your doc respond?
Not specifically to this article. She did finally agree to try lowering my levothyroxine dose and leave the Cytomel dosage alone to see if this would lower TSH. I haven't seen any worsening of symptoms since I dropped from 175 mcg to 150.
If this doesn't work, I am going to have to try to be more persuasive about the idea that she should not be using TSH to manage treatment anyway, since any amount of T3 tends to lower TSH. Unfortunately that is what the treatment guidelines from several organizations, including the American Thyroid Association, recommends. The TSH is the "gold standard."
Hope it all goes well.
well yes, but as with all vitamins (and I know it's a pro-hormone), unless we are deficient there is no benefit in taking it - apart from to those who benefit financially from selling them.
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