Broccoli, cabbage, Brussels sprouts and cauliflower are some of the well-known brassica vegetables that are loved by adults and often loathed by children. But another, sometimes forgotten member of the family, kale, is picking up popularity lately, thanks to some celebrity endorsements. Kale, like the rest of the brassica plant species, has been around for a while — it can be traced back more than 2,000 years. But recent studies have revealed that it is packed with cancer-fighting properties, and that has allowed the dark, leafy green to make a comeback in grocery stores, at farmers markets and on dinner plates.
Kale is an excellent source of calcium and vitamins A and C, but it has an incredible amount of vitamin K — 664 percent of your daily value, says Dr. Jennifer Nelson, director of clinical dietetics and nutrition at the Mayo Clinic. The vitamin promotes normal blood clotting, and a study conducted by the Mayo Clinic suggested that it may aid in preventing people from developing Non-Hodgkin Lymphoma, a common cancer that attacks the immune system.
And kale contains an abundance of flavonoids, considered antioxidants, which have anti-aging properties and have been linked to cancer prevention, Nelson says. “We’re just beginning to explore that whole family of antioxidants called flavonoids. But … you can see from (the nutrition) chart that (kale’s) a dynamite source. It’s the highest value out of all of those greens,” Nelson says, referring to a chart that includes spinach, collards and Swiss chard.
But Nelson warned that it doesn’t mean “kale is the end-all, be-all of health.”
“When you pick one food, it gets very difficult to link that one food to definitive statements … because the research right now is mostly dealing with the compounds themselves, and these compounds themselves are found in many foods,” she says. “You can just say that kale is a good source of these compounds, and these compounds are currently being explored for their roles in heart disease and cancer prevention, and these compounds are showing promise.”
That is one reason the rough, seaweed-green colored veggie is stocked in more refrigerators.
Angela Lemond, a registered dietitian, and a spokesperson for the Academy of Nutrition and Dietetics, says another reason is because kale is a good substitute for a very popular snack.
“Most recently, it has become a nutritional trend because of some online circulations of tasty kale chip recipes,” Lemond says, noting that they are healthier than the potato alternatives.
Both Lemond and Nelson suggest that people make the snack at home to avoid unhealthy additives. “If you get ready-made kale chips, some of them can be really high in sodium and fat,” Nelson says. And they’re easy to make.
But kale can be used in many dishes, too. “If you incorporate it in a variety of ways — raw, steamed, putting it into soups, using it as a bed for maybe a chunky vegetable stir fry — having it in that variety of ways allows you to obtain those nutrients in various forms,” Nelson says.
But how much do you have to have to get the nutritional benefits?
“Most nutritionists use a rule of thumb. If you’re having a cooked vegetable, for the most part, a half a cup is considered a serving,” she says. “If you’re having a raw vegetable, anywhere between a cup and two cups is considered a serving.”
People can use kale in soup, in stir-fry and in hearty salads with savory ingredients like garlic and onions. Lemond suggests people can try introducing kale into their diets by using it instead of spinach.
But kale shouldn’t be consumed by everyone. People on blood thinners such as Coumadin should avoid it, because the vitamin K can interfere with the effectiveness of the drug. “The most important thing is that it’s in a family of super greens,” Nelson says, “and if you’re not a fan of kale, you can generally find another green that is a great source of a variety of nutrients."