If you have been looking for ways to get healthy then you may have jumped on what I term the ‘kale craze bandwagon’ being peddled by a plethora of food coach’s of late, without the technical training to understand the flip side to their recommendations.
Kale is known as a cruciferous vegetable, belonging to the Brassica family, also joined by cabbage, broccoli, brussel sprouts, cauliflower and bok choy.
Now it’s a fact that the cruciferous family of vegetables are rich in vitamins, soluble fiber and selenium, with potential anticancer properties, thanks to the presence of a recently discovered compound known as Indole-3 carbinol (studies reveal this may influence cancer incidence due to its ability to alter estrogen metabolism), BUT cruciferous vegetables such as kale are also goitrogens, meaning they can induce goiter formation in people with an iodine deficiency, because they contain an enzyme that interferes with the formation of thyroid hormones.
I test every single patient’s iodine level and we are witnessing what I would describe as an epidemic in iodine deficiency, along with suboptimal thyroid function as a result. This is largely due to a poor dietary intake, especially as we are either eating refined salt that contains no iodine, or cutting salt from our diet in fear of clogging our arteries from eating too much sodium. You can read more about the health effects of salt here.
By loading up on too much kale by adding it to as many meals as possible from salads,to green juice, kale chips and kale this and kale that, you may be over doing this superfood and impairing your thyroid function. A high intake of cruciferous vegetables can inhibit the incorporation of iodine into thyroid hormone, and also the transfer of iodine into milk by the mammary gland.
Cooking cruciferous vegetables like kale for 30 minutes significantly reduces the amount of goitrogens, making them perfect for slow cooked soups and casseroles vs eating them raw, especially if you have an underactive thyroid.
So the key with this group of anti cancer vegetables is BALANCE. Yes it’s healthy to include this group of super green’s in your diet, BUT do not go overboard and be aware of your OVERALL dietary intake of all the cruciferous vegetables, especially if you have a diagnosed, or even suspected under active thyroid issue and best to cook them than consume them raw.