Vitamin DNEW2026

Vitamin D and gut microbiota in thyroid diseases: mechanisms and therapeutic potential.

Jiao Mei, Zhai Xiaodan, Jia Zheng, Gong Boshen et al. — Frontiers in immunology

Summary

甲状腺疾患は世界的に一般的な病気ですが、最近の研究では、ビタミンDの不足と腸内細菌のバランスの乱れが、これらの疾患を持つ人によく見られることが示唆されています。このレビューは、ビタミンDと腸内細菌がどのように免疫システムや腸の健康に影響を与え、甲状腺疾患の発症や進行に関与しているかを解説しています。将来的には、これらを組み合わせた治療法が期待されています。

AI-generated summary — read the original

Key points

Many people with thyroid diseases often have low vitamin D levels.
An imbalanced gut microbiome is also frequently observed in individuals with thyroid conditions.
Vitamin D and gut bacteria appear to work together to regulate the immune system and maintain gut health.
This interaction may play a role in how thyroid diseases develop and progress.

What the study looked at

This review paper explored the connection between vitamin D, gut bacteria, and thyroid diseases. **What question the study asked:** The researchers aimed to understand how vitamin D and the gut microbiome, both individually and together, might influence the development and progression of common thyroid conditions such as hyperthyroidism, hypothyroidism, and thyroid cancer. **How it was studied (design/participants):** The study was a comprehensive review, meaning the researchers gathered and analyzed existing scientific literature from various basic and clinical studies. This approach allowed them to synthesize current evidence regarding the roles of vitamin D and the gut microbiome in overall thyroid health. **What it found:** The review found that many individuals with thyroid disorders, particularly those with autoimmune thyroid disease, often exhibit both low vitamin D levels and an imbalanced gut microbiome. It highlighted that vitamin D, gut bacteria, and their byproducts (like short-chain fatty acids) all contribute to regulating the immune system and maintaining a healthy gut barrier. The paper also noted a two-way relationship: vitamin D can improve beneficial gut bacteria, while these bacteria can enhance how the body uses vitamin D. This complex interplay suggests that a combined approach targeting both vitamin D and gut health could be a promising therapeutic strategy for thyroid diseases.

Dietary takeaway

This review suggests that ensuring adequate vitamin D intake, possibly through fortified foods like milk and cereals, fatty fish, or supplements, could be beneficial for overall health, including potentially supporting thyroid health. While maintaining a diverse and healthy gut microbiome through fiber-rich foods might also be helpful, remember that this is a review of existing research, and more studies are needed to confirm direct dietary recommendations for preventing or treating thyroid diseases.

Abstract

Thyroid diseases have become the most common endocrine disorders globally, including hyperthyroidism, hypothyroidism, thyroid nodules (TN), and thyroid cancer (TC). Traditionally, the pathogenesis was attributed to autoimmune dysfunction, iodine metabolism imbalance, and genetic-environmental interactions. Recently, research suggests that vitamin D deficiency and gut microbiota dysbiosis are prevalent in patients with thyroid disorders, particularly in autoimmune thyroid disease (AITD). Vitamin D, as well as gut microbiota and its metabolites, such as short-chain fatty acids and bile acids, jointly regulate innate and adaptive immunity. They also mitigate intestinal leakage by maintaining intestinal barrier integrity, thereby influencing the development and progression of thyroid diseases. Furthermore, studies confirm the bidirectional interaction between vitamin D and the gut microbiota. Vitamin D supplementation increases the abundance of beneficial bacteria and regulates their metabolites. While beneficial bacteria and their metabolites, such as butyrate and bile acids, promote vitamin D receptor (VDR) expression and enhance vitamin D bioavailability. In this review, we integrate existing current basic and clinical evidence to systematically dissect the individual functions and reciprocal crosstalk of vitamin D and gut microbiota in thyroid diseases. Furthermore, we put forward a combined intervention of vitamin D and gut microbiota, which may serve as a viable therapeutic strategy for thyroid disease.

View on PubMed →DOI: 10.3389/fimmu.2026.1878820