Graves’ disease (GD) is an autoimmune thyroid condition, and it is the most prevalent form of hyperthyroidism. The thyroid gland plays an important role in energy metabolism and the physiology of many body systems, but it can be particularly vulnerable to oxidative damage. Recent research indicates that there may be a link between immune function, thyroid health, and the gut microbiome.

A recent study by Hou and colleagues explored the potential role of gut microbiota in the presence of GD or Graves’ orbitopathy (GO). The authors report changes in the composition of the gut microbiome in individuals with GD and GO, including increased populations of Prevotella, Lactobacillus, and Veillonella. Gut microbiome diversity has also been shown to have reductions in the presence of GD and GO. The dysbiosis associated with GD and GO may be linked to the imbalance between T helper 17 (Th17) cells and regulatory T cells and antigenic mimicry. In animal studies, increases in the incidence of autoimmune conditions have been observed in germ-free mouse models. 

Animal studies indicate that selenium may help increase gut microbial diversity. Selenium has also been shown to help support thyroid health. Selenium is an essential trace element that has been shown to support healthy thyroid hormone metabolism. It may also support antioxidant status and a normal immune response. Clinical studies indicate that supplementation with selenium may support healthy levels of antibodies associated with autoimmune thyroiditis. The genus Akkermansia may help support immune health, gut barrier protection, and metabolic function. In animal models, it has been linked with supporting health in the presence of GO.

A clinical study involving supplementation with Bifidobacterium longum along with prescription medication for 6 months reported improvements in thyroid stimulating hormone (TSH) receptor antibody levels and improvements in thyroid function and diversity among gut microbiota. Increases in short-chain fatty acids were also observed. Study design drawbacks include a relatively small sample size. 

The authors indicate that more research is needed, particularly in human populations. Clinical conclusions regarding the implications of observed changes in the gut microbiome in the presence of GD and GO cannot be made at this time. 

Studies indicate that certain nutraceuticals, such as selenium and vitamin D, may also help support thyroid function and immune health. In addition, recent research suggests that the gut microbiome may play a role in certain aspects of thyroid health. In addition, diets rich in fruits and vegetables, particularly those high in polyphenols and myo-inositol may help support healthy thyroid hormone balance, immune health, antioxidative status, and a normal response to inflammation.

By Colleen Ambrose, ND, MAT