What the Kale?

kaleKale has created a lot of buzz over the past few years due to its high amounts of vitamins and nutrients, anti-inflammatory properties and low caloric count. Some have even dubbed it “the new beef”, “the queen of greens” or “a nutritional powerhouse.” And while it offers a wide array of nutrients and beneficial properties, there is an often overlooked aspect of kale: Should it be eaten raw?

Well, the quick answer is “No.” Here’s why…

Kale is a goitrogenic vegetable. Goitrogenic substances suppress the function of the thyroid gland by interfering with iodine uptake in the thyroid. The resulting iodine deficiency is one reason goiter can develop.

While some individuals are able to tolerate a minimal amount of raw kale, the higher concentrations interfere with the ability to incorporate the iodine into the actual thyroid hormone. Therefore, even if an individual is getting sufficient amounts of iodine through food or supplementation, “it can’t be properly utilized.” Thus, making their thyroid problems worse instead of better.

Additionally, it is high in oxalates, which are naturally occurring acids that help protect “plants from being eaten by bugs or just protect them in general.”  These don’t cause problems for most people, but for some, these can make problems worse. Oxalic acid binds to other minerals, such as calcium, forming a salt known as oxalate. Oxalates (or oxalic acid interferes with the body’s absorption of calcium present in foods, such as dark leafy greens.

For example, if an individual suffers from leaky gut, the oxalates can “enter your blood, turn into crystals, and then get stored in tissues, which cause pain and inflammation.” Also, if an individual already has an increased amount of calcium in the urine, the increased oxalate could create kidney stones.

So, how does one correctly implement kale into the diet?

Studies have shown that cooking dark leafy greens removes or minimizes the oxalates. In fact, boiling markedly reduced soluble oxalate content by 30-87% and was more effective than steaming (5-53%) according to one study. When Sally Fallon Morell was asked to share her thoughts on the role of vegetables in a person’s diet, here’s what she specifically shared in regards to kale:

“I’m very concerned about people eating a lot of raw vegetables that shouldn’t be eaten raw. Of course, the favorite today is kale. People are eating kale chips or they’re using raw kale in salads or juices. Kale is full of oxalic acid; it’s full of goitrogens. I just got a letter the other day from someone who grew up eating lots of kale, and she now has a thyroid problem. It can really cause thyroid problems.”

However, it is also important to note that one doesn’t need to completely remove it from his/her diet. Instead, here are a couple of practical tips to follow:

  • Enjoy kale as a side dish. Simply par-boil it and top it with a healthy animal fat, Celtic sea salt and freshly minced garlic. This not only makes the vegetable easier to digest, but it also releases the goitrogens from the kale. And as Morell reminds us that traditional cultures never ate raw kale, she also encourages us to “think of the southern greens” when preparing a favorite kale side dish. Collard greens, another tasty goitrogenic dark leafy green and a traditional southern green, is typically braised with ham hocks. Along this same line, try adding a little bacon to your kale to take it up a few flavor notches.
  • Simply skip the idea of adding kale to your shakes or smoothies. Honestly, spare yourself. Your palate will thank you.
  • And if wanting to make a favorite kale salad, we would recommend that you choose tender bay kale well massaged or pick a different “green” option, such as bibb lettuce or romaine.

These simple suggestions will allow you to get the most out of your kale. And we’re very sure you won’t miss the raw kale!

If interested in learning more, here’s some great resources:


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