The thyroid is responsible for producing various hormones in the body that help regulate metabolism and provide support for other bodily systems, like the immune system and cardiovascular system.
Thyroid hormones help improve the absorption of nutrients from the foods we eat. They assist with gut motility. They regulate our appetites. Additionally, these hormones help boost our basal metabolic rate to burn calories. Other functions of thyroid hormones include helping metabolize glucose and break down fats. Cruciferous vegetables consist of a wide range of vegetables that contain glucosinolates or goitrogens – a sulphur compound found in kale, broccoli, arugula, turnips, cabbage, cauliflower, and other vegetables. People with thyroid problems, such as low functioning or autoimmune disorders are typically advised to avoid cruciferous vegetables due to their ‘goitrogenic’ effect.
It was previously believed that consuming cruciferous vegetables could inhibit thyroid hormone production in people with thyroid problems. Yet, the consumption of these vegetables does have health benefits, like reducing the risks of certain cancers. Various research studies have been conducted on animals where the subjects were fed cruciferous vegetables and the impacts on thyroid functions are studied. In one study, two test groups were given a diet of 7% freeze-dried rutabaga sprouts – one group with iodine deficiencies, and the other group on a sulfa-based antibiotic. Surprisingly, the spouts had a protective effect on the thyroid in test subjects that were iodine deficient. However, in test subjects that were antibiotic-treated, the initial study showed the sprouts enhanced hypothyroidism. (1) However, a second study later demonstrated the sprouts did not enhance hypothyroidism in sulfadimethoxine-treated subjects. (2) It was also noted that the consumption of the sprouts helped reduce oxidative stress on the thyroid. In both sets of test subjects, the cruciferous sprouts showed a reduction in proinflammatory cytokines. Another study in 2018 examined a 7% free-dried broccoli diet. The introduction of broccoli into the diet did not result in any changes to thyroid function. In iodine-deficient subjects, broccoli helped boost the antioxidant capacity of the thyroid. In sulfadimethoxine-treated subjects, the broccoli also helped to protect the thyroid. (3) In 2019, a study of the effects of cruciferous vegetables on thyroids in humans was conducted. Test subjects were given treated freeze-dried broccoli extract, untreated broccoli extract, or no broccoli extract for 84 days. At the conclusion of the study, subjects that received either type of broccoli extract were compared to those that receive the placebo. Finding found that certain test subjects exhibited a decrease in certain thyroid problems as the broccoli extract provided support to the thyroid. The study reported there were no noticeable changes in thyroid functioning compared to baseline findings. (4) So, are cruciferous vegetables safe for my thyroid? In conclusion, a summary of the limited research in both human and animal studies suggested that consuming cruciferous vegetables even by people with thyroid problems could potentially provide certain health benefits, such as antioxidant and anti-inflammatory effects on the gland, without a negative impact on its functioning. So the next time you read you should be avoiding broccoli if you have a thyroid condition – think again! If you have thyroid problems, have questions or concerns about thyroid disorders, and are looking for naturopathic treatment in Toronto, please feel free to contact Toronto Naturopathic Doctor, Dr. Courtney Homberg at 647-351-7282 to schedule your appointment today. Sources: