Effects of Vitamin D treatment on thyroid autoimmunity

Yet another paper about vitamin D and autoimmune thyroid disease.

Interesting that this focusses on the antibodies. Many proponents of vitamin D concentrate (understandably) on feeling well and other factors.

Again, it says nothing which might realistically help to explain why some people, including some of those with autoimmune thyroid disease, are unable to supplement with vitamin D.

J Res Med Sci. 2016 Oct 18;21:85. doi: 10.4103/1735-1995.192501. eCollection 2016.

Effects of Vitamin D treatment on thyroid autoimmunity.

Simsek Y1, Cakır I2, Yetmis M2, Dizdar OS3, Baspinar O3, Gokay F1.

Author information

1Department of Endocrinology and Metabolism, Kayseri Training and Research Hospital, Kayseri, Turkey.

2Department of Internal Medicine, Bagcilar Training and Research Hospital, Istanbul, Turkey.

3Department of Internal Medicine, Kayseri Training and Research Hospital, Kayseri, Turkey.



Vitamin D was shown to be related to autoimmune thyroid diseases (AITDs) in the previous studies. We aimed to investigate the relationship between Vitamin D and thyroid autoimmunity.


Eighty-two patients, diagnosed with AITD by the endocrinology outpatient clinic, were included in this prospective study. All of the patients had both AITD and Vitamin D deficiency, defined as serum values <20 ng/mL. They were randomly assigned into two groups. The first group included 46 patients and the second one included 36 patients. The first group was treated with Vitamin D for 1 month at 1000 IU/day. The second group served as the control group and was not treated with Vitamin D replacement. Serum thyroid-stimulating hormone, free T4 (fT4), thyroid peroxidase antibody (TPO-Ab), thyroglobulin antibody (TgAb), and Vitamin D levels were measured at the initiation of the study and again at 1 month in all patients.


Two groups were similar with regard to age, sex, and type of thyroid disease. Whereas TPO-Ab (before; 278.3 ± 218.4 IU/ml and after; 267.9 ± 200.7 IU/ml) and TgAb (before; 331.9 ± 268.1 IU/ml and after; 275.4 ± 187.3 IU/ml) levels were significantly decreased by the Vitamin D replacement therapy in group 1 (P = 0.02, P = 0.03, respectively), the evaluated parameters in the control group did not significantly change (P = 0.869, P = 0.530, respectively). In addition, thyroid function tests did not significantly change with Vitamin D replacement in two groups.


Vitamin D deficiency may contribute to the pathogenesis of AITDs. Since supplementation of the Vitamin D decreased thyroid antibody titers in this study in Vitamin D deficient subjects, in the future Vitamin D may become a part of AITDs' treatment, especially in those with Vitamin D insufficiency. Further clinical and experimental studies are required to understand the effect of Vitamin D on AITD.


Autoimmune thyroid diseases; Vitamin D; thyroid antibodies

PMID: 28163731

DOI: 10.4103/1735-1995.192501


15 Replies

  • Maybe the low dose is fine for many - could it be the higher doses often mentioned that are a problem. A 1000 iu's mentioned is not even a maintenance dose in some circles.

    It is a confusing topic. I once stopped supplementing after reading various website articles and posts. Have now returned !

  • It certainly seems reasonable to suggest that the lower the dose, the more tolerable it is likely to be. Some people struggle with even the smallest doses such as 200 or 400 IU.

  • I what way do they struggle?

  • Katepots, I'm totally intolerant to vit D supplementation. One dose of 1,000iu and I'm too weak to stand up, tired but unable to sleep, plus unable to function mentally. I've tried the small dose of 400iu daily, and by day two I'm in the same place as I would be if I took 1,000iu in one dose. It matters not which variety of supplement I take, I've tried everything from pills, capsules, spray, transdermal absorption, with and without K2, D3 and D2 versions.

    I do not suffer any of these symptoms from being out in the sun. In fact I'm at my best in the summer when I've built up my D level in the most natural way i.e. sun on bare skin as much as possible.

  • I'm also ok with the sun, not supplements. I can't tolerate B12 either. I do wonder how many members are taking high doses of vitamins and feeling awful but not making the connection.

  • Ditto B12! I wish I could make sense of why some of us can't tolerate anything whilst others can take mega doses with no ill effect.

  • I personally don't believe in taking vits anyway especially without knowing there is definitely a deficiency. It worries me that people just accept others word that they need to take these mega doses of everything regardless of needing them or not. Could that be why some people continue to feel ill, hmm i wonder !

  • Nothing is ever clear cut. Being intolerant doesn't automatically mean you don't need it, neither does being tolerant to high doses prove you do need it. The question is, how well are you? If you're feeling fantastic without any supplements then that's great. But if you're struggling every day to function, you'll understandably try all these supplements, always hoping that something will work.

    I know, I've been there, so I don't blame anyone for trying. It's important though to recognise that anything you take *may* make you feel worse.

  • That's really interesting , I still feel shocking and I'm supplementing

    Hmmm food for thought!


  • I have Graves. After my first lapse, I was advised to take vitamin D. I felt awful for the entire year I took it with muscle pain, fatigue. And I relapsed while still on vitamin D.

    I'm in remission again and this time, without vitamin D, my anti-bodies are negative, my TSH is higher and I feel a lot better.

  • Many people cannot tolerate vitd even in small doses, I'm one of them. My levels range from 12 - 30 and that's where I need to be. Maximum amount I can manage would be 800iu once a week, I don't bother.

    I have frequently advised caution when mega doses are suggested to people on the forum as taking a huge dose could well cause horrible side effects.

  • bantam12, I'm intolerant too. See my comment above.

    How does sun exposure affect you? Does your D level rise if you spend time in the sun with bare skin?

  • Yes I just replied to you above. I'm fine in the sun and my level at most gets to about 30 which is fine with me.

  • I'm amazed when I see people taking 2000UI per day. It gives muscle weakness, hence muscle pain.

    I even had nightmares with vit D. What were your symptoms?


  • I just felt really unwell and that was taking only 800iu, as soon as I stopped I was fine. I have never been able to tolerate vitamins so steer well clear.

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