Most people would choose something sweet over something green any day of the week. But if you’re looking to improve your diet or perhaps drop a few pounds, the more cruciferous vegetables you eat, the better. And if you’ve yet to discover kale, it’s time to give this green, leafy superfood a try — not only because of its low calories, but also because of the health benefits you’ll receive.
Here’s what you need to know about kale, including its nutritional facts, health benefits, health risks, and more.
Defining Kale: What Exactly Is This Green, Leafy Veggie?
Kale is a cruciferous vegetable in the same family as cabbage, cauliflower, broccoli, and collard greens. It is easily distinguishable from its family members with its purple and green leaves. As a winter vegetable, kale is a delicious choice in the cold months when other cruciferous options are less available. As a bonus, if you wait to buy kale till after a heavy frost, you may notice a sweeter taste. (1)
This popular vegetable has been around for centuries, starting off as a common vegetable in Europe. Colonists brought it to North America in the 16th century. (2)
How to Cut It: Kale
What’s in Kale Exactly? A Look at the Veggie’s Nutritional Facts
Eating well is one way to feel and look healthier. Kale is an excellent choice, providing your body with many nutrients, minerals, and vitamins, according to?the U.S. Department of Agriculture's?MyPlate?guidelines.
One cup of cooked kale has about 42 calories, 106 grams (g) of water, and 1.4 g of fat. Other nutritional facts for kale include: (3)
- 7 g of fiber (19 percent daily value [DV])
- 5 g of protein (14 percent DV)
- 3,440 international units (IU) of vitamin A (69 percent DV)
- 21 milligrams (mg) of vitamin C (35 percent DV)
- 8 micrograms (mcg) of vitamin K (617 percent DV)
- 177 mg of calcium (18 percent DV)
- 30 mg of magnesium (8 percent DV)
- 170 mg of potassium (4 percent DV)
What Are the Health Benefits of Kale Exactly?
Here are a few ways that kale can help improve your overall well-being.
Lowers the Risk of Heart Disease
The potassium in kale may help promote heart health by reducing your risk of heart disease and stroke. One study of 12,000 adults found that those who consumed 4,069 mg of potassium every day had a 37 percent lower risk of death from cardiovascular disease than those who consumed less. (4) To consume 4,000 mg of potassium from kale alone and see this benefit, you would have to eat about 15 cups of cooked kale each day, which may be a little unrealistic. (4)
But if you include more kale in your diet, along with other potassium-rich foods, you can increase your chances of getting an adequate amount in your diet.
Helps Prevent Cancer
Kale also contains potential cancer-fighting properties. It and other cruciferous vegetables contain?glucosinolates, natural sulfur compounds that gives certain vegetables their bitter taste. (5)
These compounds break down during digestion to form the active compounds indoles and isothiocyanates. Both help detoxify the body, and may hinder the growth of cancer by functioning as an anti-inflammatory and protecting DNA cells from damage. (5)
The recommended daily intake of vitamin C is 60 mg for adults, which is about 3 cups of cooked kale. (6)
Aids in Protecting Eyesight
There isn’t a recommended daily intake for either vitamin. But some experts believe there’s benefit in consuming as little as 10 mg a day of lutein and 2 mg a day of zeaxanthin from supplements. (7)
Promotes Healthy Blood Clotting
Vitamin K plays a role in healthy blood clotting, and people with a deficiency may experience slow clotting time. This can lead to excess bleeding. (8)
Vitamin K also improves bone density and supports strong bones, reducing the risk of fractures. The recommended daily dose of vitamin K for women older than 19 is 90 mcg a day, and men should have 120 mcg a day. One cup of cooked kale contains 493.8 mcg. (3,8)
Helps With Weight Loss
Because kale is low in calories and high in water, it’s an excellent food for weight loss. (3) It also contains fiber, which will help you feel full longer and prevent overeating.
There are no guidelines for how much kale to eat for weight loss. But because of its low calorie count, you can eat kale to your satisfaction and keep your calories per meal on the low end.
Kale’s high water content may also increase urination and help your body flush out excess water weight.
Improves Skin Health and Appearance
This vegetable doesn’t only improve your waistline and help reduce the risk of certain illnesses, it can also improve your skin.
Vitamin A (retinol) is essential for healthy cell growth, and a vitamin A deficiency often leads to dry skin and acne.
Although vitamin A is measured in IU, it has micrograms of retinol activity equivalents (RAE). The recommended daily amount of RAE is 900 mcg for adult men and 700 mcg for adult women. (9) One cup of kale contains the equivalent of 885 mcg of retinol activity equivalents. (3)
Contributes to Healthy Blood Sugar Levels
Manganese is a trace mineral in kale that may decrease insulin resistance, the hallmark of type 2 diabetes, and help people with type 2 diabetes maintain healthy blood sugar levels. It’s also believed that a deficiency of this mineral may predispose a person to diabetes. (10)
The recommended daily intake of manganese for adults is 2.3 mg for men and 1.8 mg for women. (10) One cup of cooked kale provides 0.54 mg, so you need to consume only between 3.33 and 4.3 cups daily. (11)
Kale vs. Spinach: What’s the Difference and Which Is Better for You?
Are you someone who prefers spinach to kale? The good news is that both veggies can have a positive impact on your health.
You can include both on your plate or alternate between the two for variety. But if you’re curious as to whether one is better than the other, here’s how these two veggies stack up.
Both veggies are great sources of vitamin A, with kale providing 3,440 IU (172 RAE) per cooked cup. But if you’re looking for the biggest vitamin A punch per serving, you’re better off with cooked spinach, which contains 18,866 IU (943 RAE) per cup. (3,12)
Fiber and Protein
Spinach also comes out on top as far as protein goes. One cup of cooked spinach boasts about 5.3 g of protein. You only get 3.5 g of protein with kale. However, kale does have slightly more fiber than spinach, 4.7 g and 4.3 g, respectively. (3,12)
Vitamin C and Vitamin K
While kale lags behind spinach with regard to protein, it does contain 21 mg of vitamin C, whereas spinach has 17.6 mg. Spinach, on the other hand, doubles kale's amount of vitamin K, with 888.5 mcg?versus kale's 493.8 mcg. (3,12)
Spinach also wins by a nose if you're particularly interested in calorie reduction. It has about 41 calories per cup, whereas kale has about 42 per cup. (3,12)
What Are the Different Types of Kale Out There?
One benefit of kale is that you can choose from a variety of types. For example: (13)
Curly kale This is the most common type of kale, and you can recognize it by its curly or ruffled edges. It’s available in different colors, including purple, dark green, and bright green.
Red kale Red kale has a slightly different appearance from curly kale. Its leaves may appear deep red or grayish green.
Lacinato/dinosaur kale This type of kale has a deeper color, with leaves that are a dark bluish-green. This type of kale is more tender than curly or red kale, making it easier to eat raw.
Baby kale With its young tender leaves, this kale is also a good choice for a raw, healthy snack.
Purple flowering kale This kale has a bitter taste and closely resembles cabbage leaves.
White flowering kale Add this kale to the menu if you prefer a peppery taste in your soups and side dishes.
Are There Any Health Risks to Eating Kale?
While kale has its benefits, eating too much of this veggie can be dangerous if you have certain medical conditions.
Because kale is a source of vitamin K, which promotes healthy blood clotting, people who take blood thinners should speak with their doctor to see how much they can safely eat. Eating too much kale may interfere with the effectiveness of these medications, especially if the amount you eat from day to day varies greatly. (14)
Eating this vegetable in large amounts may also cause an enlarged thyroid. Kale contains thiocyanate, and in large doses, this substance can trigger an iodine deficiency. Iodine contributes to healthy thyroid function, and a deficiency may lead to hypothyroidism. (15)
There are no set guidelines on how much kale to eat with these conditions. Eating small amounts should be okay. Still, talk to your doctor before adding more kale to your diet if you have any of the above health conditions. (15)
Some Simple Ideas for Cooking Kale at Home
Looking for interesting ways to prepare kale? With so many possibilities, chances are you’ll never get bored with this veggie.
Whether you prefer something easy like sautéing kale in oil, garlic, or butter, or adding a handful to soups, salads, and smoothies, here are a few ideas for when kale is on the menu.
Kale Breakfast Salad
Kale Pesto Pizza
A Final Word on Adding Kale to Your Eating Plan
Whether you’re preparing lunch, dinner, or a snack, you can’t go wrong with kale. Rotating your greens is a perfect way to add variety to your plate. You can prepare it differently each time and never get bored.
Editorial Sources and Fact-Checking
- Watson B. Taylor's Guide to Heirloom Vegetables. Houghton Mifflin. 1996.
- Munro D. Vegetables of Canada. National Research Council of Canada. 1997.
- Basic Report: 11234, Kale, Cooked, Boiled, Drained, Without Salt. U.S. Department of Agriculture Agricultural Research Service: National Nutrient Database for Standard Reference Legacy Release. April 2018.
- Davidson J, Usman M. Health Benefits of Oranges for Cooking and Health. JD-Biz Publishing. 2014.
- Cruciferous Vegetables and Cancer Prevention. National Cancer Institute. June 2, 2012.
- Vitamin C. Mayo Clinic. October 18, 2017.
- Lutein and Zeaxanthin. American Optometric Association.
- Vitamin K. National Institutes of Health. March 2, 2018.
- Vitamin A. Mayo Clinic. October 27, 2017.
- Manganese. National Center for Biotechnology Information. 2001.
- Manganese. World’s Healthiest Foods Rich in Manganese.
- Basic Report: 11458, Spinach, Cooked, Boiled, Drained, Without Salt. U.S. Department of Agriculture Agricultural Research Service: National Nutrient Database for Standard Reference Legacy Release. April 2018.
- Types of Kale. Cooking Light. November 16, 2016.
- Sheps S. Warfarin Diet: What Foods Should I Avoid??Mayo Clinic. April 19, 2018.
- Volpe K. News Update: Can Kale Cause Hypothyroidism? Endocrine?Web. March 16, 2016.