There have never been any studies on leaky gut and Hashimoto’s disease but now we have a new study on this connection. Leaky gut was something rejected by conventional medicine despite the fact that papers on leaky gut date back to the 1970s. For many years functional medicine practitioners have been testing for it and treating it which has helped many patients overcome their chronic illnesses. There are currently over 500 published scientific papers on leaky gut so there is no doubt it exists.

Before we get to the new paper, there was an interesting paper published in 2004 which looked at the gut barriers of patients with Hashimoto’s disease. The paper is entitled “Ultrastructural changes in enterocytes in subjects with Hashimoto’s thyroiditis” by Sasso et al. The authors biopsied the small intestine of patients with Hashimoto’s disease and compared the microvilli to healthy controls.

The results showed that patients with Hashimoto’s disease did in fact have structural changes in their microvilli which are the finger-like structures that line the gut barrier. Healthy microvilli are required for proper absorption of nutrients as well as preventing unwanted particles from entering the blood stream. These patients with Hashimoto’s disease had abnormal looking microvilli under the microscope compared to normal looking microvilli of the healthy controls.

The authors also performed a lactulose/mannitol test which is used to assess gut permeability. The results showed that the patients with Hashimoto’s disease had abnormal lactulose/mannitol test results indicating abnormal intestinal permeability.

Now let’s cover the new paper on leaky gut and Hashimoto’s disease entitled “Children With Hashimoto’s Thyroiditis Have Increased Intestinal Permeability: Results of a Pilot Study”.

The authors begin by discussing the connection between increased intestinal permeability (IIP) and autoimmune diseases. Zonulin is a compound that controls the tight junctions in the gut barrier which are involved in movement of nutrients in and out of the gut. The higher the zonulin levels, the more severe the increased intestinal permeability. Higher zonulin levels have also been found in patients with autoimmune disease and in those leading up to the onset of autoimmune disease.

How was the study done on Leaky Gut and Hashimoto's Disease?

30 children and adolescents with Hashimoto’s disease and 30 age, gender, and BMI matched patients with congenital hypothyroidism.

Blood tests included zonulin, TSH, free T4, anti-TPO antibodies, and anti-TG levels.

What were the study results?

Serum zonulin levels were significantly higher in the subjects with Hashimoto’s disease compared to the control group. Free T4 levels were higher in the control group but differences in TSH levels were not statistically significant. Anti-TPO and anti-TG antibody levels were higher in those with Hashimoto’s disease as we would expect.

Higher zonulin levels correlated with higher thyroid medication dose (levothyroxine). Zonulin levels did not correlate however with anti-TPO or anti-TG antibody levels.