Hashimoto’s thyroiditis is an autoimmune disease in which the thyroid gland is mistakenly assaulted by the immune system. It was the first disease to be recognized as an autoimmune disease, classified as such in 1912. It is the most common cause of thyroid disease in North America. An average of 1 to 1.5 in every 1000 people has it; it occurs ten times more frequently in women and is most common in middle age.

Symptoms of Hashimoto’s thyroiditis are variable and may include, weight gain, depression, mania, temperature sensitivity, numbness and tingling, fatigue, panic attacks, constipation, migraines, muscle weakness, cramps, memory loss, infertility and hair loss. Blood tests often show that autoantibodies are present against either peroxidase and/or thyroglobulin.

Dr Nujen Bozkurt and colleagues of the Ankara University School of Medicine in Turkey, recently conducted a cross-sectional study of 540 subjects, seeing if vitamin D levels are connected to Hashimoto’s thyroiditis.

Bozkurt NC, Karbek B, Ucan B, Sahin M, Cakal E, Ozbek M, Delibasi T. The Association Between Severity of Vitamin D Deficiency and Hashimoto’s Thyroiditis. Endocr Pract. 2013 Jan 21:1-14.

The groups consisted of 180 stable hypothyroid patients taking thyroid supplementation and 180 subjects with newly diagnosed Hashimoto’s thyroiditis, comparing them to 180 healthy controls. While 48% of Hashimoto’s thyroiditis patients had 25(OH)D levels below 10ng/ml, only 20% of the healthy controls did. Only 10 subjects had 25(OH)D ≥ 30 ng/ml and 60% of them were in the control group. Female chronic Hashimoto’s thyroiditis patients had mean 25(OH)D levels of 10 ng/ml, while male control subjects had mean levels of 19 ng/ml.

Most importantly, they found that 25(OH)D levels were directly correlated to thyroid volume and inversely correlated to anti-peroxidase (r= -0.361) and anti-thyroglobulin levels (r= -0.335), which are the antibodies involved in thyroiditis. The authors concluded,

“We showed that patients with Hashimoto’s thyroiditis present lower vitamin D levels inversely correlated to antibody levels and directly correlated to thyroid volume. Finally, our results suggested that there might be a casual relation between vitamin D deficiency and development of Hashimoto’s thyroiditis. On the other hand, there might be a possible relation between severity of vitamin D deficiency and progression of thyroid damage. However further studies are needed especially about the effects of vitamin D supplementation on prevention and/or progression of autoimmune thyroid disease.”

I predict that a growing number of studies will look at vitamin D and antibody levels in autoimmune disorders. One recent study in the same realm looked at antibodies possibly involved in autism and vitamin D levels, where Saudi Arabian researchers discovered an amazingly high correlation (r=-.86) between vitamin D levels and an antibody against human brain tissue, anti-MAG antibodies.

Study: High antibodies, low vitamin D levels in autistic children. Posted on August 17, 2012 by John Cannell, MD

In hypothyroidism, the autoimmune damage was done years ago via Hashimoto’s thyroiditis but the results are fully ameliorated by thyroid medication. That is not true of all autoimmune disorders. For example, multiple sclerosis or insulin dependent diabetes are both vitamin D associated diseases but the effects of those autoimmune assaults are to date apparently irreversible. Luckily, that is not the case with Hashimoto’s thyroiditis.