Production of Goiter in Rats with Raw and with Treated Soy Bean Flour

Soy extracts suppressed iodine uptake and stimulated the production of autoimmunogen in rat thyrocytes

“…A quadruple increase in NaI reduced the inhibition of Novasoy on iodide uptake by 25%, which is consistent with other studies showing that the anti-thyroid actions of soy can be reversed by increasing iodine intake or supplementation. 27–30 This also might be the reason why excessive soy consumption doubled the iodine requirements to maintain the normal thyroid functions as reported in animal and human studies. 27,31,32…”

Soy Protein Isolates of Varied Isoflavone Content Do Not Influence Serum Thyroid Hormones in Healthy Young Men

“…An effect of soy on thyroid function was first documented by McCarrison (4) who observed goiter in rats when raw soybeans were added to their iodine-deficient diet, an observation replicated in subsequent animal experiments (5)(6)(7). Soy has also been linked to thyroid function through case studies in the 1950s and 1960s that documented incidence of goiter in infants fed soy-based formula not fortified with iodine (8)(9)(10).…”

“…Soy has also been linked to thyroid function through case studies in the 1950s and 1960s that documented incidence of goiter in infants fed soy-based formula not fortified with iodine (8)(9)(10). These observations, although not seen with the addition of iodine (5)(6)(7)11), stimulated substantial research into the identification of a goitrogenic agent within the soybean.…”

Iodine, Thiocyanate and the Thyroid

“…Variation in the number and size of follicular cells and colloid content was observed in KI-supplemented and non-supplemented plant fed group of rats. In addition, colloid stained more with eosin in the experimental group (-KI) as compared to control and KI-supplemented (+KI) group of rat for the variation of concentration of iodine [10,11].…”