Vitamin D Does Not Improve Thyroid Autoimmunity

We’ve discussed two studies that have shown that vitamin D supplementation can lower thyroid antibodies, but a recent study found that vitamin D did not lower antibodies.  What does this mean and how to we interpret these finding?  Let’s discuss.

Dr. Michael Ruscio: Hi, this is Dr. Ruscio, and let’s discuss when vitamin D supplementation does not help with thyroid autoimmunity. We’ve discussed a number of studies in the past—two specifically—that have shown supplementation with vitamin D can help to decrease thyroid antibodies. So that’s great. That’s good news.

But let’s talk about a study that was recently published that showed that vitamin D supplementation did not help and had no effect on thyroid autoimmunity. I’ll put the abstract of the study up here on the screen, entitled “Effect of Vitamin D Deficiency Treatment on Thyroid Function and Autoimmunity Markers in Hashimoto’s Thyroiditis: A Double-Blind, Randomized, Placebo-Controlled Clinical Trial.”

And let’s go into just a couple of the details here. Fifty-six patients with Hashimoto’s thyroid autoimmunity and vitamin D deficiency. And they defined vitamin D deficiency as below 20 nanograms. And essentially half of these patients were put on vitamin D; the other half were given a placebo, and they were followed.

Now, when you look at this chart, you see something very interesting. And they were followed for 12 weeks, so it’s an adequate amount of time. If you look at the top of the table, you see vitamin D levels, and you see the vitamin D levels between the baseline and three months. And you also see it broken out by the vitamin D treatment group and by the placebo group.

You see, in the group receiving vitamin D, of course, their vitamin D blood levels increased, and the placebo group did not see an increase in their blood levels. Makes complete sense. Move down to where it says TPO-abs, your thyroid peroxidase antibodies. Probably the most clinically relevant marker to assess thyroid autoimmunity.

And when you look at the vitamin D treatment group from baseline to three months, the level of antibodies is essentially the same. You go from 820 to 734. That change is not significant. And when you look at the placebo group, you see 838 to 750. So what you’re seeing here is no appreciable effect of vitamin D supplementation on thyroid autoimmunity in this study. Their vitamin D levels increased, but the thyroid autoimmunity did not improve.

So what does this mean? Well, I think it illustrates a very important concept, which is oftentimes in complementary and alternative medicine and natural medicine, we oftentimes want to share what works, what works, what works, what works. But we don’t take as much time to share the evidence showing that something does not work.

And why that’s important is because if you only share the information, the data, that supports something working, this can lead to a false confidence that a treatment is going to be successful or a treatment must be done all the time. And so, vitamin D may be one of those. There may be some doctors or patients out there who strongly, strongly feel that you must take vitamin D if you have thyroid autoimmunity. And if your thyroid autoimmunity does not improve, you must take higher doses or take it for a longer period of time. And that’s really misguided.

The reason why it’s misguided is because vitamin D may help with thyroid autoimmunity. Some evidence certainly supports that, but it’s not to say that vitamin D treatment is a panacea for thyroid autoimmunity. Now, certainly, it’s not hard to make a case for supplementing with the vitamin D. There have been some health benefits shown, of course, for supplementing vitamin D especially when you’re deficient.

However, there’s something else very important to keep in mind here, and that is that there are benefits that one acquires from sun exposure that you cannot obtain from vitamin D supplementation. And this is very important to keep in mind. Some of the best review evidence, namely coming out of Michael Holick’s group, has shown that while we do see a vitamin D deficiency associated to a number of conditions, there does not seem to be the data to support that supplementing with vitamin D will rectify those disease associations.

Meaning, if someone with depression takes vitamin D—so someone with depression shows low vitamin D. We then give that person vitamin D. Does that vitamin D help with the depression? No. There are some trials that do show benefit with vitamin D supplementation, so it is justifiable. But the bigger point to keep in mind here is when you look at these trials more broadly, you see a trend emerge, which is there are a number of health conditions or biomarkers that will improve from sun exposure that will not improve from vitamin D supplementation.

What this simply tells you is that you cannot just take vitamin D in place of a lifestyle deficiency of not obtaining sun exposure. And the more contemporary thinking on sun exposure is showing that chronic sun exposure, meaning weekly sun exposure, is an important part of health. This does not mean spending hours at a time. Maybe 15-30 minutes a few days a week may be sufficient for most people.

So this does not mean you’re going to go to the extreme of crazy doses of sun exposure, hours at a time. However, at least a few days a week, getting 15-30 minutes in the sun between the hours of usually 11:00 and 2:00 in the sunny months is a very important health practice. And this may help with obtaining health benefits that you cannot obtain from vitamin D supplementation alone.

But back to the issue at hand regarding vitamin D supplementation and thyroid autoimmunity, it can help, but it’s not a guarantee. Certainly, something to add into your therapeutic repertoire for thyroid autoimmunity, but it’s not the only piece and all of the data does not show benefit. So just keep that in mind when supplementing with vitamin D to try and aid and improve your thyroid autoimmunity. And also, remember, do not look at vitamin D supplementation as a way to avoid a very important lifestyle practice of obtaining routine exposure to the sun and time outside.

Ok. This is Dr. Ruscio, and I hope this information helps you get healthy and get back to your life. Thanks.