Do cruciferous vegetables like kale cause hypothyroidism? Dr. Chaudhry explains the relationship between these vegetables and your thyroid.
Keeping a healthy diet is important for thyroid health, but there is a common concern about certain foods you should not have in order to avoid thyroid problems like hyperthyroidism or hypothyroidism.
There has been a lot of attention to cruciferous vegetables and their impact on thyroid health. Cruciferous vegetables include kale, cabbage, broccoli, cauliflower, collard greens, and more.
These vegetables contain thiocyanates and there is some concern that these thiocyanates may interfere with thyroid hormone synthesis and iodine uptake by the thyroid gland, and thus increasing the risk of hypothyroidism. However, the thiocyanates in these foods are largely inactivated by cooking or even by steaming the vegetables.
Cruciferous vegetables have numerous health benefits including antioxidants with cancer protective effects. These benefits outweigh the potential decrease in thyroid function, which would only theoretically occur if one consumed excessive amounts of cruciferous vegetables and if one is iodine deficient.
The United States is actually considered iodine replete (meaning most people get enough iodine), however, vegans and those individuals who are under restricted diets may be iodine deficient, so this may be a theoretical risk for those patients.
You can safely eat two to three servings of raw cruciferous vegetables especially if you are iodine replete.
Dr. Chaudhry is an endocrinologist at NYU Langone Health in New York City.
Thyroid Diseases. Bethesda, MD: US National Library of Medicine, 2015. (Accessed on November 20, 2015 at https://www.nlm.nih.gov/medlineplus/thyroiddiseases.html).
Hypothyroidism and Pregnancy. Washington, DC: Endocrine Society, 2015. (Accessed on November 20, 2015 at http://www.hormone.org/patient-guides/2012/hypothyroidism-after-pregnancy).
Hashimoto’s Disease. Bethesda, MD: National Endocrine and Metabolic Diseases Information Service, 2015. (Accessed on November 20, 2015 at http://www.niddk.nih.gov/health-information/health-topics/endocrine/hashimotos-disease/Documents/hashimoto_508.pdf).
Cruciferous Vegetables. Micronutrient Information Center of University of Oregon. Corvallis, OR. 2017. (Downloaded on 11/11/2018 at )
Hypothyroidism, spinach and kale. Mayo Clinic. Rochester, MN. 2016. (Downloaded 11/11/2018 at )
Felker et al. Concentrations of thiocyanate and goitrin in human plasma, their precursor concentrations in brassica vegetables, and associated potential risk for hypothyroidism. Nutrition Reviews. Vol 74 (4): 248-258.
Can Kale cause Hypothyroidism. Endocrineweb. Montclair, NJ. 2016. Downloaded 11/11/2018 at
Thyroid Disease and Pregnancy. National Institute of Diabetes and Digestive and Kidney Diseases. Maryland. 2017 (Downloaded 11/11.2018 at )