Kale kale kale kale kale—if you're been paying attention to eating healthfully over the last, oh, two decades or so, you'll know that this leafy green is a powerhouse of nutrition.
And for good reason.
As Dr. Annelie Vogt von Heselholt, R.D., founder of DietitianDoc - Cancer Nutrition Made Simple , says, kale is a cruciferous powerhouse vegetable that’s cousins with broccoli, cabbage, Brussels sprouts, and kohlrabi.
“It’s been hailed as a superfood and consists of over 50 different varieties,” she says, adding that it’s low in calories and high in fiber, antioxidants, vitamins, minerals, and plant compounds.
Vogt von Heselholt elaborates: “Because many of those nutrients are antioxidants with anti-inflammatory properties, kale is, according to a study in Molecules in 2022, considered anti-inflammatory and important for the immune system .” Kale may help prevent heart disease and lower the risk of cancer .
Kale is so healthy, Nichole Dandrea, M.S., R.D.N., author of The Fiber Effect: Stop Counting Calories and Start Counting Fiber for Better Health , suggests her clients try to consume daily.
This is due to kale's abundance of nutrients in exchange for very little calories, making it an exceptionally nutrient-dense food, she says. “With its high amount of fiber, carotenoids, potassium, folate, vitamin C, vitamin B6, magnesium, calcium, and vitamin K1, as well as its phytonutrients like chlorophyll, glucosinolates, quercetin, and flavonols, kale is truly a superfood."
There's even more to love about kale: “Its high fiber content supports a healthy gut. The beta carotene found in kale is converted to vitamin A in the body, where it acts as an antioxidant, scavenging free radicals. The magnesium and calcium support bone health,” says Dandrea.
“Magnesium, folate, and B6 also support cognition and a good mood. Vitamin K1 is an essential component of bone building and blood clotting," she says. "Vitamin C supports the immune system and potassium is perfect for replenishing electrolytes after an intense workout.”
Dandrea also says that cruciferous vegetables, such as kale, are also packed with nitrates that convert to nitric oxide in the body, increasing blood flow and, potentially, performance.
Of course, it’s important to keep in mind that kale is not a cure all.
“No single food—not even kale—is a saving grace by itself. Instead, food items work best in concert,” says Vogt von Heselholt. “Health promotion and disease prevention are multi-faceted approaches that should be incorporated into your everyday life for the duration. It includes eating plenty of fruits, vegetables, nuts and seeds, whole grains, beans and lentils, herbs and spices, fatty fish and seafood, drinking water, exercising daily, and staying a healthy weight."
A healthy lifestyle also includes avoiding fast foods, red and processed meats, sugary drinks, and alcohol, not smoking, and cutting stress. “Thus, rather than just implementing one strategy, you can rest assured that you are doing everything you can to protect your body in the best way possible,” said Vogt von Heselholt.
Ahead, a look at what makes kale so great for you, plus easy ways to incorporate it into your diet.
Kale Nutrition Facts
On the macronutrient level, one cup of chopped raw kale contains:
33 calories, 2 grams (g) protein, 6g carbohydrates (1g fiber), and 0.5g fat
In terms of micronutrients, here's how things shake out.
- 684% of DV* of vitamin K
- 206% DV of vitamin A
- 134% DV of vitamin C
- 26% DV of manganese
- 10% DV of copper
- 9% DV of vitamin B6, calcium, and potassium
- 6% DV of magnesium and iron
- 1-5% DV of the B-vitamins thiamine, riboflavin, folate, niacin, and pantothenic acid, and the minerals phosphorus, zinc, and selenium
*DV=Daily Value, based on 2,000 calories.
And then a few nutrients worth calling out:
You absorb more calcium from a cup of kale than a cup of milk?! That’s right.
“Kale has approximately 254 mg of calcium per cup, but it's not just the amount of calcium in a food that's important, it's the bioavailability that is key. For example, 1 cup of dairy milk has 305 mg of calcium, but its bioavailability is approximately 35 percent so 107 mg of calcium is actually absorbed,” says Dandrea.
“The bioavailability of calcium in kale is approximately 65 percent, which means 165 mg of calcium is absorbed. So, technically, kale delivers more calcium per cup than milk, making it an ideal food to meet calcium requirements. What's more, kale also delivers fiber and phytonutrients, two nutrients that are key to optimal health and not found in dairy.”
This nutrient does a lot for you.
“Magnesium is involved in more than 300 enzyme systems that regulate a variety of biochemical reactions in the body, including protein synthesis, muscle and nerve function, blood glucose control, and blood pressure regulation. Magnesium has been shown to support cardiovascular health , blood pressure control, diabetes management, bone health, mood and cognition. Magnesium is essential for the conversion of muscle glycogen to glucose, your body’s fuel during intense exercise, as it is needed to generate ATP (adenosine triphosphate),” says Dandrea.
“Without sufficient magnesium, lactic acid build-up, resulting in muscle soreness and fatigue. It is also key in protein synthesis, aiding in recovery. Magnesium plays a key role in performance, training goals, recovery, and bone health. In fact, every cell in your body contains it and needs it to function.”
Beta-Carotene and Lutein
These antioxidants are essential for your health. And you guessed it, kale has ‘em.
“Beta-carotene and lutein are two carotenoids that are found in abundance in kale,” says Dandrea, noting that beta-carotene is a type of carotenoid that is converted into vitamin A in the body.
“Vitamin A is a fat soluble vitamin that can be toxic in high amounts when taken as pure vitamin A. The beauty of plant-based or preformed vitamin A, in the form of carotene, is that your body regulates how much carotene is converted to vitamin A based on your individual needs, which may prevent toxic loads,” she says, and adds that vitamin A is essential for eye health, skin health, and a healthy immune system.
“Lutein is not converted to vitamin A, but acts like an antioxidant in the body and is also essential for eye health, preventing macular degeneration. There is also evidence showing carotenoids' role in cardiovascular health and cognition.”
“Kale is also very high in plant compounds that work as antioxidants . These include glucosinolates such as indole-3-carbinol and sulforaphane, polyphenols such as quercetin, kaempferol, and anthocyanins,” says Vogt von Heselholt, also reiterating that kale has carotenoids such as beta-carotene, lutein, and zeaxanthin. “They’re anti-inflammatory, important for the immune system, eye, and heart health, and can help reduce the risk for cancer.”
“A single cup of kale provides upwards of 7 times the recommended intake of phylloquinone, or vitamin K. Vitamin K is a fat-soluble vitamin that is essential for the synthesis of coagulation proteins needed for blood clotting . Since it’s not well absorbed, it’s best to eat it with oil. Vitamin K is also involved in bone health , and although low vitamin K levels are associated with a higher risk of fractures, it’s unclear if supplementing with vitamin K is effective,” says Vogt von Heselholt. “Vitamin K is also believed to play a part in heart health by lowering the risk of atherosclerosis. Further research is needed to determine who might benefit from increased dietary intake or supplementation.”
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One important note if you take blood thinners or have a loved one who does: “A high intake of vitamin K can be a concern for people on blood thinners, especially those on warfarin therapy for stroke prevention,” says Vogt von Heselholt. “Since vitamin K and warfarin have opposite functions, keeping your intake consistent is recommended so the dose can be dialed in.”
Another vitamin win from Team Kale.
“A cup of kale provides 2 times the need for vitamin A, or more accurately, the antioxidant beta-carotene that the intestines, liver, and kidneys can turn into vitamin A,” says Vogt von Heselholt. “Vitamin A is important for immune function, communication between cells , and heart, lung, and eye health."
Oranges are great for vitamin C, but so is kale.
“One cup of kale provides well over 100% of the body’s needs for vitamin C. It has four times as much vitamin C as spinach . Vitamin C is a water-soluble antioxidant that is anti-inflammatory. It’s essential for the immune system by helping fight free radical damage in the body that helps prevent chronic diseases and may reduce the risk of cancer,” says Vogt von Heselholt. “Vitamin C also helps form collagen in the skin and tissues, tendons, bones, and cartilage. It may also help prevent high blood pressure and heart disease , and improve iron absorption .”
How to Add More Kale to Your Diet
There are so many ways to enjoy kale, from kale-infused protein shakes to a sauteed kale side dish with dinner.
“You can eat it raw in salads, add it to smoothies and protein shakes, steam it for five-to-10 minutes, make kale chips in the oven with sea salt, sauté it with olive oil, mushrooms, and garlic, or add it to stews, casseroles, omelets, and bowls,” says Vogt von Heselholt.
“Chopping raw kale and working it between your fingers with olive oil or salad dressing can improve both the sweetness and absorption of carotenoids, sulforaphane, and fat-soluble nutrients. Boiling kale results in loss of vitamin C and, to a lesser extent, beta-carotene, while steaming and stir-frying both preserves nutrients better and improve the flavor .”
One of Dandrea’s go-to ways to incorporate kale is by chopping the leaves into tiny pieces and adding them to homemade veggie burgers where they're cooked into the burger. “You don't even know the kale is there, but your body knows it's getting lots of nutrition. My point is, don’t give up on kale until you’ve tried it in a variety of ways. Add kale to your plate as a part of a nutrient-dense meal plan for optimal health.”
Perri is a New York City-born-and-based writer; she holds a bachelor's in psychology from Columbia University and is also a culinary school graduate of the plant-based Natural Gourmet Institute, which is now the Natural Gourmet Center at Institute Of Culinary Education. Her work has appeared in the New York Post, Men's Journal, Rolling Stone, Oprah Daily, Insider.com, Architectural Digest, Southern Living, and more. She's probably seen Dave Matthews Band in your hometown, and she'll never turn down a bloody mary. Learn more at VeganWhenSober.com.