Did you know that certain foods can obstruct iodine absorption? Yes, consumption of foods that contain goitrogens, which are substances that interfere with the uptake of iodine in the thyroid, can exacerbate iodine deficiency. Goitrogens are compounds found in certain foods. When consumed in excess, they can interfere with the normal function of the thyroid gland. They make it more difficult for the thyroid to produce the hormones your body needs for normal metabolic function. The link between goitrogens and thyroid function was first described in 1928 when scientists observed thyroid gland enlargement in rabbits eating fresh cabbage. This enlargement of the thyroid gland is also known as a goiter, which is where the term goitrogen comes from. Goiter is commonly the noticeable sign of iodine deficiency; however, brain damage, mental retardation, procreative failure, and childhood mortality are more grave consequences that goitrogens may pose. The discovery led to the hypothesis that substances in some vegetables may affect thyroid function when consumed in excess.

There are three main types of goitrogens. These are goitrins, thiocyanates, and flavonoids. Goitrins and thiocyanates are produced when plants are damaged, such as when they’re sliced or chewed. Flavonoids are naturally present in a wide variety of foods. Some examples include resveratrol in red wine and the catechins in green tea. These are generally considered to be healthy antioxidants, but some of them can be converted into goitrogenic compounds by our gut bacteria. For people with thyroid problems, high intake of goitrogens can worsen thyroid function by preventing iodine from entering the thyroid gland, which is needed to produce thyroid hormones; interfering with thyroid peroxidase (TPO) enzyme that attaches iodine to the amino acid tyrosine, which together forms the basis of thyroid hormones; and interfere with thyroid-stimulating hormone (TSH), which helps the thyroid gland produce hormones.

Goitrogens can reduce the thyroid’s ability to produce the hormones your body needs to function normally. When the thyroid’s function is disrupted, it has trouble producing the hormones that regulate your metabolism. This can lead to problems controlling body temperature, heart rate, protein production, calcium levels in the blood, and how your body uses fats and carbs. Goitrogens are found in a wide variety of cruciferous vegetables, fruits, starchy plants, and soy-based foods. Foods high in goitrogens include soy, cassava, and cruciferous vegetables such as cabbage, broccoli, and cauliflower. A varied diet, cooking foods, avoiding smoking, and getting enough iodine and selenium are simple ways to reduce the effects of goitrogens.

PNFP Rowence Zorilla, RND

References:

Petre, A. (2017). Are Goitrogens in Foods Harmful? Retrieved October 22, 2021 from the Healthline website: https://www.healthline.com/nutrition/goitrogens-in-foods

Chandra, A. (2010). Goitrogen in Food. Retrieved November 3, 2021 from the Science Direct website: https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/goitrogens