Does Vitamin D Supplementation Affect Subclinical Hypothyroidism

vitamin D multivitamin
vitamin D multivitamin
Researchers noted a significant increase in serum vitamin D and significant reductions in TSH following 3 months of vitamin D supplementation.

A significant decrease in thyroid stimulating hormone (TSH) level and anti TPO titre was seen when patients with autoimmune subclinical hypothyroidism (SCH) and vitamin D deficiency received vitamin D replacement, according to a study presented at the the 26th American Association of Clinical Endocrinologists Annual Scientific Sessions & Clinical Congress. 

To date, there have been no studies assessing the outcome of vitamin D replacement on SCH. Study authors from King Fahad Medical City and King Abdualziz Medical City, led by Naji Aljohani, MD, SBIM, FACE, FACP, hypothesized that replacing vitamin D in deficient patients with SCH would result in reduced TSH levels and anti TPO titres. To test this, they performed an observational, prospective study in Saudi patients with SCH and vitamin D deficiency. 

At baseline, the mean TSH was 6.0 mIU/L, mean Free T4 was 14.4 pmol/L, mean anti TPO antibody titre was 343.4 IU/mL, and mean vitamin D level was 25.2 nmol/L. 

After 3 months of treatment with vitamin D, the researchers found a significant increase in serum vitamin D to 59.6 nmol/L (=.0001) as well as significant reductions in TSH to 4.9 mIU/L (=.001) and anti TPO titre to 125.1 IU/mL (=.057). 

“We showed that replacing vitamin D has a significant impact on improving SCH, measured by a significant reduction in both TSH and anti TPO antibody titre after 3 months of treatment,” said Dr Aljohani. A subgroup stratified by vitamin D status, however, indicated that the reduction was only significant for those with vitamin D deficiency. 

Due to the small sample size, the authors acknowledge that bigger randomized controlled trials are needed to validate these findings.

Visit Endocrinology Advisor‘s conference section for continuous coverage from AACE 2017

Related Articles


Aljohani N, Brema I, Ansari M, Khan S, Almousawi F, AlSharani A. The effect of vitamin D replacement on subclinical hypothyroidism. Abstract 1073. Presented at: 26th American Association of Clinical Endocrinologists Annual Scientific Sessions & Clinical Congress; May 3-7, 2017; Austin, TX.

This article originally appeared on MPR