At least once a day I am asked by one of my patients whether or not they can eat raw cruciferous vegetables. They are concerned that fresh pressed juice for breakfast or a raw kale salad for lunch will damage their thyroid gland. I decided to write this newsletter to address this topic, once and for all! Especially because now is the time for spring cleanses and when everyone wants to eat raw veggies!
Is Kale Bad? Kale and other cruciferous vegetables, such as cabbage, Brussels sprouts, broccoli, broccolini, cauliflower, mustard greens, turnips, and collards contain a compound called isothiocyanates, which like soy isoflavones, appear to block an enzyme in the thyroid called TPO. This enzyme is responsible for attaching iodine to the thyroid hormones to make them active. Basically, these vegetables are thought to block your body from using the iodine that it needs. If the thyroid doesn’t have enough iodine, the cells start overgrowing and the thyroid gets bigger–this is called a ‘goiter’. That’s why these foods are often called ‘goitrogens’, because they make the thyroid swell as it is trying harder to make your thyroid hormones with limited raw materials.
Kale and other cruciferous vegetables are only considered to be goitrogens when they are eaten raw. When these vegetables are cooked or lightly steamed, this issue goes away. Does this mean you should never eat raw vegetables? Absolutely not! Life after all, is about balance, and nature would not have given us these bountiful plant foods if they weren’t good for us. If you always avoid all of these foods your diet will be very restricted, and you would miss a lot of important nutrients. But on the flip side, I do not advocate eating raw cruciferous vegetables at every meal, every day. Either extreme is not a good idea. But eating them daily at 1 or 2 meals is okay, and periodically doing a medically sound liquid cleanse or detox program is fine, too, as long as you are getting enough iodine in your diet. At Blum Center for Health we have several medically supervised individual and group detoxes to choose from. I also created the Juice Cleanse + detox programs at Organic Pharmer , with or without food.
Focusing on increasing your iodine intake will help you supply your thyroid with what it needs, and this can offset the goitrogen effect from these foods. Now you can see why the main strategy to preventing a goiter from occurring due to eating raw foods, is to make sure you are getting enough iodine every day! How should you do this? Read on and Mary will focus on this in our nutrition section below.