Soy hinders Iodine in the body

November 8, 2018


Soybeans contain goitrogenic substances. Goitrogens hinder thyroid hormones by disrupting the uptake of iodine. Sometimes, simply increasing iodine in the diet can be enough to counteract this disruption. However, certain goitrogens, in large enough amounts, can actually impair the thyroid from utilizing iodine, even with iodine supplementation. Iodine is a crucial nutrient. It is involved in such things as metabolism, fertility, immunity, brain growth and health, radiation protection, bone health, detoxification, energy, etc. Many researchers believe that iodine deficiency is more common than usually realized, especially with so much in the diet and environment that lacks, or hinders, iodine.


Soy has many “anti-nutrients,” and there are many reasons to avoid it, especially in regard to hormonal health and fertility. But the goitrogenic property is often overlooked. Perhaps the following information will help many who may be suffering from symptoms of iodine deficiency, who may routinely ingest large amounts of soy. (Soy is added to numerous processed foods): 


“The existence of goitrogens in soybeans was shown by McCarrison (1933) who observed thyroid enlargement in young rats fed a soybean diet. These results were confirmed by Sharpless (1938)…”
(Vitamins and Hormones, Volume 10, 1952)


“Thyroid Disorders are the commonest amongst the various glandular disorders of the endocrine system…According to a recently released report, about 300 million people in the world are suffering from this endocrine problem…Soy or soy enriched foods can also aggravate thyroid problems reducing T4 absorption and interfering with thyroid hormone action…and are reported to increase auto-immune thyroid disease…One of the studies reported the development of goiter and hypothyroidism in a 10-month-old infant who was put on soybean product right from birth but it reversed with soybean product withdrawal and Lugol’s iodine drops. In addition, thyroid showed high uptake of I131 after soybean product withdrawal. Studies on adults revealed significant suppression in plasma-bound I131while receiving soybean product…Thus soybean product seemed to contain goitrogenic agent which affects thyroid function…”
(J Clin Diagn Res. 2016 Jan)


“Goitrogenic and estrogenic activity of soy isoflavones…Iodine deficiency greatly increases soy antithyroid effects, whereas iodine supplementation is protective. Thus, soy effects on the thyroid involve the critical relationship between iodine status and thyroid function…the possibility that widely consumed soy products may cause harm in the human population via either or both estrogenic and goitrogenic activities is of concern…”
(Environ Health Perspect. 2002 Jun)


Two of the FDA’s expert researchers on soy, sent their employer a letter of protest:


"...there is abundant evidence that some of the isoflavones found in soy, including genistein and equol, a metabolize of daidzen, demonstrate toxicity in estrogen sensitive tissues and in the thyroid. This is true for a number of species, including humans. Additionally, isoflavones are inhibitors of the thyroid peroxidase which makes T3 and T4. Inhibition can be expected to generate thyroid abnormalities, including goiter and autoimmune thyroiditis. There exists a significant body of animal data that demonstrates goitrogenic and even carcinogenic effects of soy products. Moreover, there are significant reports of goitrogenic effects from soy consumption in human infants and adults." (Doerge and Sheehan, Feb. 18, 1999)


“The effects on the thyroid gland of soybeans administered experimentally in healthy subjects… These findings suggested that excessive soybean ingestion for a certain duration might suppress thyroid function and cause goiters in healthy people, especially elderly subjects…”
(Nihon Naibunpi, Gakkai Zasshi. 1991 May; Japanese study)


“The occurrence of a potent goitrogen in soybean flour and meal is well documented…”
(Iodine in Foods, 1974)


“Working with chickens and rats, it was found that soybeans contain a goitrogenic substance. Rations for chicks containing only 12 per cent of soybean-oil-meal caused an enlargement of the thyroid gland.”
(Journal of the American Veterinary Medical Association, 1944)


There are already enough reasons to avoid soy. This is icing on the soy-meal cake!












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