Medically Reviewed by Poonam Sachdev on July 19, 2023
4 min read

Kale is a dark, leafy green you can eat raw or cooked.

This superfood has been on dinner plates since Roman times. The vegetable comes from the cabbage family, which also includes broccoli, cauliflower, and collards.

Kale is packed with vitamins and minerals.

Nutrients in kale can also help you:

In most cases, kale is a great addition to any diet. But in very high amounts, kale and its cousins in the cabbage family can interact with how your thyroid gland works. If you have hypothyroidism, also known as an underactive thyroid, ask your doctor about how certain foods can affect your thyroid.

The vitamin K in kale is a benefit to most people but can interfere with the effects of some blood thinners. If you take blood thinners, check with your doctor before adding kale to your diet. If you eat about the same amount of leafy green vegetables every day, it may allow your doctor to adjust your medication so that you can safely enjoy the greens' other health benefits.

Kale is also rich in the mineral potassium. Normally, your kidneys balance the amount of potassium you take in with what you lose when you pee. But if you take certain medications or your kidneys don't work as well as they should, the levels of potassium in your blood can get too high. This condition is called hyperkalemia. It can damage your heart as well as lead to kidney failure. 

If you have kidney damage or take beta-blockers for high blood pressure, ask your doctor if you should try to limit potassium in your diet to control or prevent hyperkalemia. They can tell you which foods are highest in potassium. They may recommend that you follow a low-potassium diet.



Kale can be curly or flat or even have a bluish tint mixed in with the green. The flavors are different, so try them all.

The types include:

  • Curly kale: bright green ruffled leaves, the most common type of kale
  • Dinosaur kale: narrow, wrinkly green leaves attached to a thick stem
  • Redbor kale: ruffled leaves that vary in color from deep red to purple
  • Russian kale: less common, and has flat leaves with a fringe that range from green to red to purple

Many farmers markets sell several types of kale, and most major grocery stores should have at least one. If you have a garden or even just a few containers on a patio, you can grow kale.

Whether you buy kale from the store or pluck it from your own backyard, look for crisp, dark leaves. When you get ready to cook or eat it, remove the leaves from the tougher stalks.

100 grams (one cup) of raw kale has:

  • 43 calories
  • 2.92 grams of protein
  • 4.1 grams of fiber

Select dark green bunches of kale with small or medium leaves. Avoid any with leaves that are yellowed, wilted, or have a strong smell. These will stay fresh and tender for about 5 days in the refrigerator. Wash kale thoroughly before using.

Add kale to pasta sauce, pesto, hummus, casseroles, smoothies, or soup. Or try one of these methods:

Sauté, roast, or steam it. Be sure to dry the leaves thoroughly for best results. The middle rib is edible, but most people find it bitter and remove it before cooking. A splash of olive oil and a little onion or garlic are all this veggie needs, and it cooks up in minutes. The leaf is tougher than spinach leaves, so it won’t wilt as quickly in the pan.

Make a kale Caesar salad. You can eat kale raw in a salad. The leaves can stand up to heavy dressings. Kale Caesar salads have popped up on many restaurant menus. You can whip up a homemade mustard-based dressing that has all the thickness of Caesar but fewer calories.

Bake kale chips. Bake kale in the oven with just a little olive oil drizzled over lightly salted leaves. Store-bought kale chips can sometimes be deep-fried or come with a coating of cheese, so check labels to make sure you’re not reaching for a high-calorie snack.

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Photo credit: iStock/Getty Images


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U.S. Department of Agriculture: “Kale, raw.”

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University of Georgia: “Nutrition for Older Adults’ Health.”

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Mayo Clinic: “Are you getting enough calcium?” “The many types and health benefits of kale.”

Harvard School of Public Health: “Ask the Expert: Omega-3 Fatty Acids,” “Sizing up ‘superfoods’ for heart health,” “Vitamin A,” “Vitamin K,” “Vitamin C,” “Kale.”

University of Maryland Medical Center: “Hypothyroidism.”

Oregon State University: “Cruciferous vegetables.”

Nutrition Research: “Steam cooking significantly improves in vitro bile acid binding of collard greens, kale, mustard greens, broccoli, green bell pepper, and cabbage.”

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UpToDate: "Patient education: Low-potassium diet (Beyond the Basics)."

National Kidney Foundation: "Your Kidneys and High Potassium (Hyperkalemia)," "Hyperkalemia (high potassium)."

University of Nebraska-Lincoln: "Kale." 

Penn Medicine: "The Truth About Blood Thinners, Leafy Greens, And Vitamin K."

Nephrology Dialysis Transplantation: "Hyperkalemia: pathophysiology, risk factors and consequences." 

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