In a Chinese study, researchers looked at vitamin D and autoimmune thyroid disease status in their patients. Their study evaluated 66 patients (34 had Hashimoto's disease and 32 had Graves' disease), compared to 52 healthy controls. They measured the serum D3, calcium, parathyroid hormone, Free T3, Free T4, Thyroid Stimulating Hormone (TSH), Thyroid Peroxidase Antibodies (TPOAb), and Thyroglobulin Antibodies (TgAb) in all the patients studied.

They found that the patients with autoimmune thyroid disease had Vitamin D3 levels that were significantly lower than the controls. And, interestingly, almost 82% of the autoimmune thyroid disease patients had low Vitamin D. The study defined low Vitamin D as a level of less than 20 ng/ml. The patients who had especially high TPO antibodies — above 1300 — showed significantly lower Vitamin D3 levels.

The researchers concluded that vitamin D deficiency was associated with higher TPO antibodies in autoimmune thyroid patients. This suggests that vitamin D insufficiency may be linked to or in part caused by autoimmune thyroid disease.

In another poster presentation, Brazilian researchers focused on the prevalence of vitamin D insufficiency and the link to thyroid size, function and autoimmunity markers in Hashimoto's patients. They studied 54 Hashimoto's patients, compared to 54 healthy controls. Vitamin D3 25, TSH, Free T4, Thyroid Peroxidase antibodies, Thyroglobulin antibodies, and Thyroid Receptor Antibodies were among the levels evaluated. An ultrasound was done to evaluate thyroid volume. They also studied collected data on weight, height, body mass index and time since diagnosis.

The researchers found vitamin D deficiency in 63.2% of the patients, compared to almost 37% in the control group. Among the Hashimoto's patients, a lower level of Vitamin D was associated with a higher TSH level and larger thyroid.

The researchers concluded that low vitamin D is involved in the disease process that causes Hashimoto's thyroiditis, and that vitamin D and autoimmune thyroid disease are linked.

What This Means for Thyroid Patients

This is not the first time we've heard about a link between Vitamin D deficiency and thyroid problems. But it's becoming increasingly clear that Vitamin D evaluation and assessment should become a standard part of thyroid evaluation and care.

If you are being treated for a thyroid condition, or are euthyroid ("normal" thyroid levels) but have elevated thyroid antibodies, it's time to have your Vitamin D tested. Specifically, ask for the 25-hydroxy Vitamin D blood test.

If your levels are low, discuss appropriate Vitamin D supplementation with your physician. (Note: Vitamin D is best absorbed when taken with the dinnertime meal, and some amount of fat in the meal to aid in absorption.)

And keep in mind, that while conventional medicine considers level within the Vitamin D reference range to be "normal," many physicians now feel that optimally, the general public should fall at least in the middle of the reference range.

Integrative and holistic physicians frequently recommend that the levels for people with autoimmune disease or thyroid disease be maintained at even higher levels, around the 75th percentile of normal. (That means, if the reference range is 20-100, the general target is 50-60, and for autoimmune and thyroid patients, 60-80.

If you're looking for a way to boost your levels, try this high-quality Vitamin D supplement from HoltraCeuticals!


Botelho, I.M. et. al., "Hashimoto's Thyroiditis and Vitamin D Insufficiency: Study of Prevalence and Relationship with Thyroid Autoimmunity Markers," "Abstracts from the American Thyroid Association," Thyroid, Volume 24, Supplement 1, 2014, Poster 19, October 2014 Online

Chen, G. et. al. "Serum Vitamin D3 Level in Patients with Autoimmune Thyroid Diseases," "Abstracts from the American Thyroid Association," Thyroid, Volume 24, Supplement 1, 2014, Poster 18, October 2014 Online

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