Kale has become the unofficial mascot of the healthy living movement. To live well these days, it seems like kale smoothies, juices, bowls and salads are required. It is perhaps a final endorsement of kale’s position as king of the greens that McDonald’s just announced it will be testing kale breakfast bowls in several California locations. But is the leafy green really all it’s cracked up to be? We asked Rustik’s resident dietician, Diana Chard, to investigate.
Q: What’s the deal with kale? Is it really all that? Is it much better for you than spinach?
A: Kale has undergone a serious image overhaul in recent years. It has evolved from being a decoration in salad bars and seafood display cases to being perhaps the most popular so-called ‘superfood’ (But let’s not get into the whole superfood debate right now. We can save it for a later discussion, when we look at unicorns and other mythical creatures).
By now, you must have heard of – and possibly tasted – kale smoothies, salads, and chips, the latter for which people seem willing to pay exorbitantly! Seriously –six dollars for a little bag of flavoured leaves? Most of the time, people either love kale, or hate it, but everyone seems to agree that we should all be eating more of it.
Most of the time, people either love kale, or hate it, but everyone seems to agree that we should all be eating more of it.
Kale has been touted as a good source of iron, protein, fibre and calcium. While it does contain small amounts of all of these nutrients you’d have to eat quite a bit of it to obtain any considerable benefit. One cup of raw kale contains: 1.2 mg of iron, 2.2 g of protein, 1.3 g fibre, and 90 mg of calcium. It is, however, a great source of vitamin A, vitamin C, and vitamin K, providing more than 100 percent of the recommended daily intake in just one cup. It’s also a good source of potassium, folate, and several other trace minerals. At just 33 calories per cup, that’s a pretty good nutritional bargain. But how does it compare to spinach, the leafy green that it dethroned in the smoothie stratosphere?
One cup of raw spinach (bearing in mind that by weight this is equivalent to about half a serving of kale) has: 0.8 mg of iron, 0.9 g protein, 0.7 g fibre, and 29.7 mg of calcium. Spinach is similarly a great source of vitamin A and vitamin K, and a good source of vitamin C, folate, and additional trace minerals. By volume it seems that kale is superior to spinach, but by weight they’re close contenders.
Of course, in the face of its meteoric rise in popularity, kale has also faced a backlash. There have been some concerns raised about the fact that kale contains goitrogens. These are substances that can impede the function of the thyroid by preventing iodine uptake.
Have you ever heard of goiters? These growths are generally the result of diets rich in goitrogen-containing foods combined with limited iodine consumption. Even with the diminished consumption of iodine as a result of people spurning table salt in North America, there is little likelihood of developing a goiter by consuming kale smoothies or chips.
Other dark leafy greens also contain these goitrogens, so there’s no benefit in rushing back into the arms of spinach. If you are truly concerned, you might want to try cooking your leafy greens, which destroys goitrogens. In addition, consuming a varied diet – including an assortment of dark leafy greens – is the best way to meet your nutrient needs and maintain good health.
All leafy greens – kale, spinach, mustard greens, beet greens or collard greens – are rich in nutrients and can make a great salad. However, kale’s got them all beat on one front: it definitely makes the best chip!
Editor’s note: Rustik’s favourite recipe for kale chips is this one, from Jacques Pépin (scroll to about 16:15 if you’re in a hurry)