"Preliminary research has tied oxalate build-up to thyroid disease, and while I’ve never had a problem with oxalates (knock on wood), other thyroid patients have reported oxalate issues.
While oxalate build-up has been predominantly tied to kidney stone formation, a study of thyroid autopsies found that 79% of adults were found to have oxalate crystals in their thyroid glands, with prevalence increasing with age. Interestingly, people with Hashimoto’s had a lower incidence of oxalate crystals, especially in the parts of their thyroid gland that were inflamed! This led the scientists to conclude that oxalates may play a role in contributing to Hashimoto’s, potentially causing inflammation that may trigger the autoimmune response that results in destruction of the oxalate crystals and the surrounding thyroid tissue. In some cases, giant cell reactions were found around the crystals, suggesting an ongoing immune response.1"