Leaky Gut And Thyroid Health

Leaky Gut And Thyroid Health

Before we start, other blogs that you might be interested in, include:

Leaky Gut And Thyroid Health

Hashimoto thyroiditis (HT) is the most common autoimmune disease worldwide, characterized by chronic inflammation and circulating autoantibodies against thyroid peroxidase and thyroglobulin.

There is a lot of evidence that the intestinal dysbiosis, bacterial overgrowth, and increased intestinal permeability favour the hashimoto’s development, and a thyroid–gut axis has been proposed, which seems to impact our entire metabolism (1).

Hashimoto thyroiditis has become a global public health concern, and the worldwide prevalence reaches 10–12%, affecting 10 times more women (1)

What Might Cause Hashimoto’s?

Although the HT etiology remains unknown, epidemiological studies suggest that HT is caused by an interaction between genetic and environmental factors. Enrionment factors may include:

  • Excessive iodine consumption.
  • Selenium deficiency
  • Iron deficiency
  • Zinc deficiency
  • Vitamin D deficiency
  • Bacterial infections, such as Helicobacter pylori and Yersinia enterocolitica.
  • Viral infections, such as hepatitis C, Epstein–Barr virus, and enteroviruses.
  • Smoking.
  • Pollutants.
  • Chemical agents
  • Stress.
  • Climate.

The Gut Microbiome And Thyroid Health

We observed a significant increase in the Bacteroides species and a decrease in Bifidobacterium in samples of patients with Hashimoto’s. In addition, Lactobacillus species were higher in patients without thyroid hormone replacement, compared with those who use oral levothyroxine (1).

In addition, the microbiome may play role in thyroid disorders by influencing neurotransmitters, the hypothalamus–pituitary axis, the dopamine production, and consequently the TSH secretion.

SIBO And Thyroid Health

In this study, the authors also observed significant differences in Lactobacillus abundance between patients who realised thyroid hormone replacement therapy and those who did not. Lactobacillus are acid-lactic producing bacteria and belong to the Firmicutes phylum, the second most prevalent in the human gut. Recently, a study showed that Lactobacillus promote gut barrier integrity.

The authors suggested that this increase in Lactobacillus in patients with no hormone replacement could be associated with the small intestinal bacterial overgrowth (SIBO) in patients with Hashimoto’s.

Other researchers studies 50 patients with Hashimoto’s and 40 controls and found that 54% of patients presented SIBO, in contrast with the control group.

SIBO is a common cause of leaky gut. Read my blog SIBO and Thyroid Connection for more information on this specific topic.

Leaky Gut And Thyroid Health

The researches detected increased zonulin concentrations (a marker of leaky gut), suggesting a leaky gut in patients with HT. These findings could help understand the development and progression of HT (1).[/vc_column_text]


Conclusions: Leaky Gut And Thyroid Health

The authors concluded that there are alterations in the microbiome and the integrity of the gut lining in Brazilian patients with Hashimoto’s. In addition, they suggested that diet might have played an important role in modulating the gut microbiome in patients with Hashimoto’s. (1)


  1. Detection of Alterations in the Gut Microbiota and Intestinal Permeability in Patients With Hashimoto Thyroiditis (click here)
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Alex is a certified Functional Medicine Practitioner (IFMCP) and has a MSc in Personalised Nutrition. He is also a breathwork facilitator with a background in personal training and massage therapy. He also runs The Resiliency Program - a 24 week program aimed at building physical, mental, emotional, and spiritual resilience.

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