Kale

Kale may be best known for its deep green colour and signature curly leaves, but it’s really its nutrient content that deserves special attention.  Packed with vitamins A, C and K, as well as a host of other nutrients, kale is a vegetable should be adding to your menu in 2011.  Read this month’s featured food and find out how to add this superfood to your diet.  

Kale

Nutrition Notes

Kale is one vegetable that deserves a place on your dinner plate in the year ahead. It's low in calories, fat free and packed with a range of vitamins and minerals, including vitamins A, C and K, as well as phytochemicals called lutein and zeaxanthin.  

Kale - and other leafy green vegetables - have been linked with a lower risk of cancer, heart disease and osteoporosis.  Other studies have shown that eating just one daily serving of green leafy vegetables can reduce the risk of heart disease by up to 23 percent.  

Your eyes can benefit from eating kale too.   Kale is an excellent source of lutein and zeaxanthin, two phytochemicals that when consumed, make their way to the eye where they protect both the retina and lens from oxidative damage. A number of studies linked higher lutein intakes with a lower risk of cataract and macular degeneration. Scientists speculate that a daily intake of 6 to 15 milligrams of lutein and zeaxanthin is optimal for eye health. And guess what? One-half cup (125 ml) of cooked kale has 12 milligrams!

Eating kale regularly can also help keep your mind sharp as you age, thanks to its exceptional vitamin E content.  Vitamin E is thought to protect brain cells from damage caused by free radicals. The brain is especially vulnerable to free radical damage because of its high demand for oxygen, its abundance of easily oxidized cell membranes, and its weak antioxidant defenses.

If you need another reason to eat your greens it's because they're good for your bones, thanks to their sizeable vitamin K content.  Research from the Human Nutrition Center on Aging at Tufts University revealed that compared to women who consumed the most vitamin K, those whose diets provided the least had significantly lower bone density. Scientists speculate it takes about 200 micrograms per day to protect bones from thinning.  One serving of cooked kale (1/2 cup or 125 ml) delivers 531 micrograms of the nutrient!!

Nutrient information per ½ cup (125 ml) of cooked kale;

Calories
19 kcal
Fat
0.3 g
Protein
1.3 g
Carbohydrate
4 g
Fibre
1.4 g
Vitamin C
28 mg
Retinol
468 mg
Vitamin K
531 mcg
Potassium
157 mg
Calcium
49 mg
Folate
9 mcg
Iron
0.6 mg
Lutein
12 mg

Source: Canadian Nutrient File, 2007b

Varieties

Kale belongs to the Brassica family of vegetables that also includes broccoli, cabbage collards and Brussels sprouts.   Kale is also known as borecole, or curly cabbage.

Kale comes in many varieties and colours, although the Scotch variety is the most widely consumed, with its signature deep green leaves and ruffled leaves.  

Other varieties of kale may be yellow, red or purple and have either flat or ruffled leaves.  Coloured varieties of kale are often used for ornamental purposes. They are edible but have a much stronger flavour than Scotch kale.

Buying

Although it is available year round, kale is best bought from the middle of winter to the beginning of spring when it has a sweeter taste than the rest of the year.

Look for kale with firm, deeply coloured leaves and hardy stems.  The leaves should have a deep green colour.  Avoid kale that is yellow, brown or wilted.  Choose smaller bunches of kale as they will be more tender and have a milder flavour than bunches with large, coarse leaves.

Storing

You can store unwashed kale in the crisper in your refrigerator for up to one week.  To extend the shelf life of kale, wrap it in a moist towel before putting it in the fridge.  

The longer you store kale, the stronger its flavour becomes, so try to use it within 7 to 10 days of purchasing.

Preparing

Kale requires little preparation. It can be steamed, sautéed, braised or added to soups, stews and casseroles.  Once cooked, it can be eaten hot or cold.

To prepare kale, rinse leaves under cool running water; be sure to remove any sand or grit from the leaves and stems.  To remove stems, simply fold a leaf in half and pull up on the stem, which will tear off easily.  Depending on the dish you are making, you can tear the leaves into bite sizes pieces once washed and stemmed.

Kale requires slightly longer cooking times than other more delicate leafy greens, such as spinach or Swiss chard.  Here are some easy ways to prepare kale:

Blanching: Drop prepared kale into a large pot of boiling water. Cook just until wilted. Cooking time will vary (10-15 minutes) depending on how tender or coarse the kale is. Drain thoroughly and cool before squeezing out any excess moisture. The cooling process can be hastened by running cold water over the blanched kale.

Braising: Braising is a great way to give kale a richer flavor. After sautéing, add a little chicken or vegetable broth to the pan. Cover and cook for 8-10 minutes. Remove the lid and continue cooking until the broth evaporates. It can then be seasoned with some olive oil, salt and pepper and served as a side dish or used as an ingredient in another recipe.

Sautéing: Kale can be sautéed after being blanched or without blanching using a good stock. If it is blanched first, all it takes is a little olive or other vegetable oil (2-3 tbsp. for a large bunch) and a quick heating in a large saucepan. For smaller amounts, cut back on the oil accordingly.

If you'd rather sauté without any added fat, broth substitutes nicely. In a non-stick saucepan, put enough low-sodium chicken or vegetable stock to generously cover the bottom. For extra seasoning, add finely chopped garlic, onions, leeks or shallots. Bring to a boil and toss in prepared kale. Lower the temperature to medium-high and simmer until kale is limp and wilted but not mushy. Cooking time will vary from 3 to 15 minutes. You may need to add more stock to the pan as it evaporates.

Steaming: Tender young kale can be steamed using only the water left on the leaves after washing (or very little added water or stock). Toss into a non-stick saucepan, cover and cook over medium heat until wilted. If the pan begins to dry out, simply add ¼ cup (60 ml) water or stock to the pan.   Cooking time varies between 10 and 12 minutes.

Eating

Kale has a mild peppery taste.  It's delicious eaten on its own or added to soups, salads, casseroles, stir-fries and pasta dishes.

Healthy ways to enjoy

Breakfast
  • Add chopped kale to an egg-white omelet along with sliced red bell peppers and chopped leeks.
  • Add finely chopped kale to both a quiche or frittatas.

Lunch
  • Toss lightly sautéed tender young kale leaves into a bean salad or add to a cold pasta salad.
  • Add chopped raw kale to hearty soups during the last 10 minutes of cooking.
  • Use tender young kale leaves on a sandwich or in a wrap in place of lettuce or spinach.

Dinner
  • Sauté kale with olive oil, crushed garlic, red pepper flakes and balsamic vinegar for a tasty side dish. Season with a pinch of sea salt and freshly ground black pepper.
  • Add tender young kale leaves to homemade pizza - they taste especially good when paired with tomatoes, sliced red onions and red bell peppers.
  • Toss in bite-sized pieces of kale leaves to your favourite stir-fry.
  • Stir cooked kale into a pot of warm, garlic-mashed potatoes.

Snacks
  • Forget potato chips, try kale chips! They're just as tasty, and far more nutritious. Click here for the recipe.

Did you know?

  • Kale originated in the Mediterranean and was introduced to North America by the English in the 7th century.
  • Researchers have identified over 45 different flavonoids (a class of phytochemicals) in kale.
  • Growing your own kale? If harvested after a light frost, kale will have a sweeter flavour.

More Information

The World’s Healthiest Foods

Canadian Living

Metro Grocer