Kale (borecole) is a form of cabbage, in which the central leaves do not form a head. It is considered to be closer to wild cabbage than most domesticated forms. The leaves have a distinctive ruffly appearance that distinguishes the plant from a close relative, collard greens. Other vegetables in the family are broccoli, bok choy, cabbage, brussels sprouts, cauliflower, radishes, mustard and turnips. The list is quite extensive. One thing that binds all these vegetables is the enzyme composition and their health benefits. This vegetable tends to be a little bit bitter in flavor, although this bitterness is tempered by washing, cooking, and using younger leaves. It may be eaten raw, but since the leaves are somewhat tough, kale is usually cooked.
Through the Middle Ages, kale was one of the most common green vegetables in all of Europe. Curly leafed varieties of cabbage already existed along with flat leafed varieties in Greece in the fourth century BC. These forms, which were referred to by the Romans as Sabellian kale (straight leafed), are considered to be the ancestors of modern kales. Today one may differentiate between varieties according to the low, intermediate, or high length of the stem, with varying leaf types. The leaf colors range from light green through green, dark green and violet-green to violet-brown. Russian kale (the leaves are frilly and oak leaved in shape and red veined, greenish purple in color) was introduced into Canada and then into the U.S. by Russian traders in the 19th century.During World War II, the cultivation of kale in the United Kingdom was encouraged by the Dig for Victory campaign. The vegetable was easy to grow and provided important nutrients to supplement those missing from a normal diet because of rationing.
Kale is very high in beta carotene, vitamin K, vitamin C, lutein, zeaxanthin, and reasonably rich in calcium. Kale, as with broccoli and other brassicas, contains sulforaphane (particularly when chopped or minced), a chemical with potent anti-cancer properties. Sulforaphane is synthesized from two compounds found in cruciferous vegetables called glucoraphanin (one of the bitter glucosinolates) and myrosinase, which are released when kale or other cruciferous vegetables are prepared and when they're chewed. Boiling decreases the level of sulforaphane; however, steaming, microwaving, or stir frying do not result in significant loss. Along with other brassica vegetables, kale is also a source of indole-3-carbinol, a chemical which boosts DNA repair in cells and appears to block the growth of cancer cells. Kale is also a good source of carotenoids.
Kales can be classified by leaf type. The types include Curly leaved (Scots Kale), Plain leaved, Rape Kale, Leaf and spear (a cross between curly leaved and plain leaved Kale) and Cavolo nero (Tuscan Kale, Dinosaur kale).
Kale Super Food Qualities
All vegetables have vitamins, minerals and nutritional benefits, but not all vegetables are created equal, and some deserve a little more attention. Kale is one of these super vegetables.
Kale has been used from the Middle Ages, but has become increasing popular among the health conscious for its antioxidants and anti-inflammatory properties. Its anti-cancer nutrients can be found in the form of Isothiocyanates (ITCs) made from glucosinolates in kale.
Kale is high in fiber, and the isothiocyanates (ITCs) in kale have been shown to help detoxify the body's cells. The fiber in kale has been shown to be particularly good at lowering cholesterol because of the vegetable's interaction with bile acids.
Upon tasting kale, some find it too earthy or bitter. However, there are many different ways of preparing it, and it is used in Mediterranean, Northern European, African and Asian cuisines. It can be eaten raw or cooked, in stir-fries, soups, smoothies, salads, casseroles, etc. Although it is often eaten raw in salads, its cholesterol fighting properties are actually more efficacious when it is cooked (steamed kale, sautéed or boiled). Raw kale still has cholesterol-lowering ability--just not as much.
Kale Health Benefits
Kale has made a name for itself as a highly nutritious, super-vegetable. Kale's cancer preventive benefits have been clearly linked to its unusual concentration of two types of antioxidants, namely, carotenoids and flavonoids. Antioxidants are beneficial to the body because they prevent the build up of a harmful bi-product of your metabolic processes, namely "oxidative stress." Within the carotenoids, lutein and beta-carotene are standout antioxidants in kale.
Kale also contains at least 45 different antioxidant flavonoids, including kaempferol and quercetin. Kale's flavonoids have both antioxidant and anti-inflammatory benefits, and for this reason have anti-cancer properties.
Studies on five forms of cancer -- bladder, colon, breast, ovarian and prostate - have shown that the consistent consumption of cruciferous vegetables, e.g. kale, support the prevention of cancer. A clear link has been found with kale's cancer preventive benefits and its unusually high concentration antioxidants. The Isothiocyanates (ITCs) made from glucosinolates in kale have also been linked to cancer-fighting properties.
Kale is also rich in omega-3 fatty acids. Consuming 100 calories of kale (approximately three cups) provide the body with 25-35% of the National Academy of Sciences' public health recommendation for the most basic omega-3 fatty acid (alpha-linolenic acid, or ALA). This omega-3 fatty acid has anti-inflammatory properties. Inflammation in the body has been linked to a range of disease, including cancer.
When we eat kale, the fiber-related nutrients interact with bile acids in the intestines and prevent the bile acids from being emulsified with the fat. Our livers use cholesterol in the production of bile acids. Bile acids are used in the body to aid with digestion and the absorption of fats through a process known as emulsification. Kale interacts with the bile acids, helping the body absorb more cholesterol.
The fiber-related components in kale do a better job of binding together with bile acids in your digestive tract when they've been cooked (cooked (steamed, sautéd or boiled). Cooking breaks down the fiber in kale, helping them interact with the bile acids. When the binding process takes place, it's easier for bile acids to be excreted, and the result is a lowering of your cholesterol levels. Raw kale still has cholesterol-lowering ability--just not as much.
Among the more basic benefits of eating kale are its high levels of vitamins. One cup of kale provides the body with 1,327.6% of the daily recommended value of vitamin K. Kale also provides 354.1% of the daily recommended value of vitamin A and well over half of one's daily recommended value of vitamin C. Other nutrients one can expect to find in kale include manganese, dietary fiber, copper, tryptophan, calcium, potassium, iron, magnesium, vitamin E and many others.
It has been documented in the Environmental Working Group's 2012 report "Shopper's Guide to Pesticides in Produce," kale is among the 14 foods on which pesticide residues are most frequently found. If you are wanting to avoid pesticide-associated health risks, you may want to buy organic kale.
Like brussel sprouts, cauliflower, broccoli, mustard, canola oil, peanuts and soy, kale contains goitrogen. Normally, excess levels of goitrogen are simply flushed out by the liver, however, persons with thyroid problems should be careful about kale consumption.
Kale Storage and Preparation Tips
- Store kale carefully if you aren't going to use it immediately. Wrap the leaves in paper towels and keep them in the salad crisper of your refrigerator for up to 5 days. Wash at the time of use of the kale.
- Wash kale thoroughly before cooking. Fill a clean washbasin or your sink with cold water and submerge the kale leaves. Swirl the leaves around with your hands and drain. The grit drops to the bottom.
Recipe tips for Kale
- Cook tender young greens briefly in a stir-fry or steam before serving. You must boil mature kale vigorously for several minutes to soften the rigid cellulose structure.
- Season your cooked kale simply with lemon juice, salt, olive oil and pepper. You can use finely chopped kale in vegetable soup or as a pizza topping.
- Make a simple salad with a bunch of thinly sliced kale, red pepper, onion, raisins, and your favorite salad dressing.
- Braise chopped kale and apples, garnish with chopped walnuts, and add a splash of balsamic vinegar.
- Toss whole-grain pasta with chopped kale, pine nuts, feta cheese, and a little olive oil.
- Cover and cook a pound of chopped kale with a few garlic cloves and 2 tablespoons olive oil for 5 minutes; season with salt, pepper, and a tablespoon of red wine vinegar.
- Make kale chips by slicing kale into bite-size pieces, toss with a drizzle of olive oil and a pinch of salt, and bake for 10-15 minutes at 350 degrees in the oven.
- Kale leaves have thick fibrous stems. They stems are edible, so leave them in if you enjoy crunchy foods. Or you can take them out, if you are not used to eating lots of fiber, or if you want to make a more delicate dish. To strip out the stems, grasp a kale leaf with one hand by the stem. Wrap your other hand firmly around the lower end of the leafy part. Slide your hand up the leaf, staying close to the stem, to strip off the leafy part. Drop the leaf onto the cutting board, and do another one. If you are making a blended soup or green smoothie, leave the stems in.
- To chop kale, lay a bunch of kale on the cutting board and cut crosswise into strips. Turn the cutting board 90°, and cut again if you want smaller pieces. Or cut kale leaves crosswise with a kitchen scissors. Or just tear into pieces with your hands.
Recipes for Kale
Yield 5 servings
Links spicy pork sausage links, sliced, 12
Vegetable oil - 1tablespoon
Diced onion - ¾ cup
Minced garlic - 1¼ teaspoon
Chicken soup base - 2 tablespoons
Water - 4 cups
Potatoes, halved and sliced - 2
Sliced kale - 2 cups
Heavy cream - 1/3 cup
- lace sausage links in a large sauce pan and cook per package instructions or until cooked through. Slice into 1/2 inch slices. Remove from the pan.
- in the same pan, heat oil over medium heat. Saute onions until translucent; add garlic and cook 1 minute.
- Stir in broth, water and potatoes; simmer 15 minutes.
- Reduce heat to low and add sausage, kale and cream; simmer until heated through and serve.
Sweet and Savory Kale
Yield 6 servings
Olive oil - 2 tablespoons
Onion, diced - 1 small
Garlic, 2 cloves, minced
Dijon mustard - 1 tablespoon
White sugar - 4 teaspoons
Cider vinegar - 1 tablespoon
Chicken broth - 1 1/2 cups
Kale stemmed, torn and rinsed - 4 cups
Cranberries, dried - 1/4 cup
Salt and pepper to taste
Sliced almonds - 1/4 cup
- Heat olive oil in a large pot over medium heat. Stir in the onion and garlic; cook and stir until the onion softens and turns translucent, about 5 minutes.
- Stir in the mustard, sugar, vinegar, and chicken stock, and bring to a boil over high heat.
- Stir in the kale, cover, and cook 5 minutes until wilted.
- Stir in the dried cranberries, and continue boiling, uncovered, until the liquid has reduced by about half, and the cranberries have softened, about 15 minutes. Season to taste with salt and pepper.
- Sprinkle with sliced almonds before serving.
Vegetarian Kale Soup
Yield 8 servings
Olive oil - 2 tablespoons
Yellow onion, chopped - 1
Chopped garlic - 2 tablespoons
Kale, stems removed and leaves chopped - 1 bunch
Water - 8 cups
Vegetable bouillon (such as Knorr) - 6 cubes
Tomatoes, diced - 2 cups
White potatoes, peeled and cubed - 6
Cannellini beans (drained if desired) - 2 (15 ounce) cans
Italian seasoning - 1 tablespoon
Dried parsley - 2 tablespoons
Salt and pepper to taste
- Heat the olive oil in a large soup pot; cook the onion and garlic until soft.
- Stir in the kale and cook until wilted, about 2 minutes.
- Stir in the water, vegetable bouillon, tomatoes, potatoes, beans, Italian seasoning, and parsley.
- Simmer soup on medium heat for 25 minutes, or until potatoes are cooked through.
- Season with salt and pepper to taste.
Yield 4 servings
Kale, stems removed and thinly sliced - 1 bunch
Carrot, grated -1 large
Orange, juiced - ½
Lemon, juiced - ½
Salt and freshly ground black pepper
Olive oil - 1 tablespoon
Red onion, sliced very thinly - ½
Bacon, cooked crisp and chopped - 1 slice - optional
Mayonnaise - 1 rounded tablespoon
- Place the thinly sliced kale into a salad bowl.
- Toss with the carrot, orange juice, lemon juice ,and salt, and using your hands, rub the acid into the kale.
- Let the kale sit while you shock the onion.
- Prepare a large bowl of ice water and a saucepan with boiling water. Place the thinly sliced onion into the boiling water for 15 to 30 seconds, and then shock them in the cold water, stopping the cooking immediately.
- Drain the water and blot the onions with a paper towel.
- Add the onion, bacon, olive oil, salt and pepper and toss well.
- Add the mayonnaise and mix the slaw well. Refrigerate until ready to serve.
- Can be made several hours in advance.
White bean, squash and kale soup
Yields 6 servings
Dried white beans (cannellini), 1 pound
Coarsely chopped, 2 onions,
Olive oil, 2 tablespoons
Garlic cloves, 4 minced
Chicken broth, 5 cups
Water, 2 quarts
Salt, 2 teaspoons
Black pepper, 1/2 teaspoon
Bay leaf, 1
Finely chopped fresh rosemary, 1 teaspoon
Butternut squash, 1/2 peeled, seeded and cut into 1/2-inch cubes
Kielbasa, 1 pound sliced crosswise 1/4-inch thick
Kale, washed, stems and center ribs discarded, and chopped, 1 pound
Soak beans overnight, changing the water several times.
Simmer the beans in enough water to cover them for about 30 minutes, or until they are about half way to tender.
Saute onions in oil in a large pot over medium-low heat until softened, 4 to 5 minutes.
Add garlic and cook, stirring, 1 minute.
Add beans, broth, 1 quart water, salt, pepper, bay leaf, and rosemary and simmer, uncovered, about 20 minutes.
Add the squash and simmer another 30 minutes until beans and squash are tender.
While soup is simmering, brown kielbasa in a heavy skillet over medium heat, then transfer to paper towels to drain.
Stir in kale, sausage and remaining quart of water and simmer uncovered, until kale is tender, 12 to 15 minutes.
Season soup with salt and pepper and serve.