Do you live for your kale smoothies, kale chips, or sautéed kale? If so, you’re not alone.
Kale has great nutritional properties that you might be aware of, but have you heard there’s also a darker side to kale? Things aren’t all sunshine and roses in kale land, though: eat too much of the leafy green brassica vegetable and you increase your risk of developing hypothyroidism, which I covered in our Guide to Thyroid Health.
Kale is a vegetable in the same family as cauliflower, collard greens, broccoli, and Brussels sprouts. It’s super-high in Vitamin K, calcium, Vitamin C, and beta carotene. It has powerful anti-cancer properties and aids in DNA repair in the body’s cells.
So where does the risk come in?
Kale and Hypothyroidism
Kale (and all the other cruciferous vegetables) have high amounts of glucosinolates, sulfur-containing compounds that form goitrin. Goitrin suppresses the function of the thyroid gland when it interferes with iodine uptake. Iodine deficiency, which results, causes an enlargement of the thyroid.
When you have a high intake of any cruciferous vegetable, or any other goitrogen, you can develop thyroid problems. A kale smoothie once every few days isn’t going to cause any harm, unless you have an underlying thyroid condition, but when you eat it every day, you run the risk of developing issues, especially if you also avoid iodized salt like so many other Paleo eaters (sea salt and Himalayan salt does not have iodine added).
Hypothyroidism is an endocrine disorder where the thyroid gland fails to produce enough of the thyroid hormone. The condition can cause weight gain without associated appetite, hoarse voice, poor hearing, constipation, abnormal sensation, tiredness, and poor ability to tolerate cold temperatures. Signs of an under-active thyroid are hair loss, carpal tunnel syndrome, swelling of the arms and legs, slow pulse rate, dry skin, and cool extremities. The main cause of hypothyroidism worldwide is a deficiency in iodine. People with hypothyroidism should avoid or limit goitrogens.
Unless you’re eating 15 cups worth of kale a day, you’re probably not in any risk of developing hypothyroidism; however, if you have already been diagnosed with the condition, you should definitely limit your intake of raw cruciferous vegetables.
Speak to your health care provider to be sure, but you probably shouldn’t completely cut these veg from your diet, either, because the health benefits are too numerous to ignore.
Benefits of Kale
As mentioned, the benefits of kale are numerous:
- Lowers cholesterol
- Reduces risk of cancer of the breast, colon, bladder, prostate, and ovary
- Helps detox the body
- Offers both antioxidant and anti-inflammatory benefits
How to Select, Store, and Prepare Kale
First off, choose organic when possible, because kale is on the “Dirty Dozen” list. Look for bunches with firm leaves and crispy stems. Younger kale is tender and less bitter. Keep it in the fridge in a plastic bag. Wash it right before you use it.
Rinse it under running water and shake off as much water as possible. Cut into small pieces and let it sit at least five minutes before cooking. The best way to cook kale is to steam it since this allows you to get the most from its nutritional benefits.
You can also eat it raw, either just as it is in a salad or in smoothies. Try drying it out with some light seasoning and enjoy kale chips.
What are your thoughts on kale?
(Related: Is Dairy Paleo?)