Are Goitrogenic Foods Good For Thyroid Patients?

Vegetables such as cabbage, broccoli, cauliflower, and spinach are considered goitrogenic foods because they contain naturally-occurring substances that cause “goiter” or swelling of the thyroid gland. They make it more difficult for the thyroid gland to produce the hormones your body needs for normal metabolic function. It is essential for individuals suffering from hypothyroidism to be aware of goitrogenic foods. Learning about goitrogenic foods could help you understand What are goitrogens? How do goitrogenic foods interfere with thyroid function? Which foods are considered goitrogenic? How to reduce the risk of goitrogenic foods?

What Are Goitrogens?

Goitrogens are substances that disrupt the production of thyroid hormones and are classified based on their chemical structure as Thiocyanate Isothiocyanate Cyanogenic glucosides Thionamides Glucosinolates Thiourea, and Flavonoids1.

How Do Goitrogenic Foods Interfere With Thyroid Function?

Goitrogenic foods inhibit thyroid hormones synthesis by

• Blocking Iodine
• Interfering with Thyroperoxidase (TPO)1,2

Blocking Iodine:

Goitrogens such as glucosinolates, metabolites, cyanogenic glucosides, thiocyanates compete with iodine for thyroidal uptake, thus preventing iodine from entering the thyroid gland1.

Interfering With TPO:

Thyroperoxidase is a critical enzyme that attaches iodine to the amino acid tyrosine, resulting in the production of thyroxine (T4) or triiodothyronine (T3). Goitrogens such as Cyanogenic compounds (Thiocyanate or Isothiocyanate, thionamide, or thiourea) impair the activity of TPO, thereby causing reduced hormone synthesis leading to hypothyroidism1,3.

Which Foods Are Considered Goitrogenic?

• Cruciferous Vegetables and Fruits: Vegetables from the genus Brassica, including broccoli, brussels sprouts, cabbage, canola, cauliflower, collard greens, contain glucosinolates. Mustard, turnip, and radish are relatively rich in thiocyanate. Bamboo shoots, sweet potato, tapioca, and cassava are rich in cyanogenic glucosides. The Rosaceae family of fruits, including apricots, cherries, peaches, pears, plums, raspberries, and strawberries, are also examples of goitrogens. All these goitrogens can decrease iodine uptake into the thyroid gland, thereby affecting the synthesis of thyroid hormone4,5.

• Soy Products : Soy products contain compounds such as isoflavones that can lower thyroid hormone synthesis6.

• Pearl Millet : Pearl millet is rich in C-glycosylflavones. Some studies found that C-glycosylflavones inhibited 85% of the TPO (Thyroid Peroxidase enzyme), thus leading to difficulty in producing thyroid hormones7.

How To Reduce The Risk Of Goitrogenic Foods?

All these foods contain many essential nutrients and contribute towards a healthy balanced diet. If you have an underactive thyroid or are worried about goitrogens in your diet, there are a few simple ways to reduce the risk.

• Various procedures like soaking, washing, boiling, and cooking can help reduce the goitrogenic potency of these foods.
• Steaming, roasting, or sauteing veggies instead of raw them helps break down goitrogenic compounds.
• If you are fond of greens such as spinach, try blanching and then freezing them, limiting their impact on the thyroid gland8. Refer to the recipe instructions in the Hint app for a detailed description of these procedures.
• For example, Palak saag contains spinach which has potent goitrogens. But by following the process of blanching, you can reduce the effect of goitrogen present and safely consume them by following these precautions.

If you suffer from hypothyroidism and have any more questions about consuming such foods, please feel free to contact us at support@clearcals.com or +91 8886667634.

REFERENCES:

1.Chandra Amar K, Iodine, Thiocyanate and the Thyroid, Biochem Pharmacol (Los Angel), an open-access journal, Volume 4; Issue 3; 1000171. {:target="_blank"}

2.Goitrogens, Environmental Eduardo Gaitan, in Encyclopedia of Endocrine Diseases, 2004

3.Thyroid hormones, antithyroid drugs Morris J. Brown MA MSc FRCP FAHA FBPharmacolS FMedSci, in Clinical Pharmacology, 2019

4.Chandra AK, Mukhopadhyay S, Lahari D, Tripathy S. Goitrogenic content of Indian cyanogenic plant foods & their in vitro anti-thyroidal activity. Indian J Med Res. 2004 May;119(5):180-5. PMID: 15218979.

5.Felker P, Bunch R, Leung AM. Concentrations of thiocyanate and goitrin in human plasma, their precursor concentrations in brassica vegetables, and associated potential risk for hypothyroidism. Nutr Rev. 2016;74(4):248-258. doi:10.1093/nutrit/nuv110

6.Messina M, Redmond G. Effects of soy protein and soybean isoflavones on thyroid function in healthy adults and hypothyroid patients: a review of the relevant literature.

7.E Gaitan, R H Lindsay, R D Reichert, S H Ingbar, R C Cooksey, J Legan, E F Meydrech, J Hill, K Kubota; Antithyroid and goitrogenic effects of millet: role of C-glycosylflavones, J Clin Endocrinol Metab. 1989 Apr;68(4):707-14. doi: 10.1210/jcem-68-4-707.

8.Rungapamestry V, Duncan AJ, Fuller Z, Ratcliffe B. Effect of cooking brassica vegetables on the subsequent hydrolysis and metabolic fate of glucosinolates. Proc Nutr Soc. 2007 Feb;66(1):69-81. doi: 10.1017/S0029665107005319. PMID: 17343774. {:target="_blank"}