There are three main types of kale: curly kale — green curly leaves best known as a garnish, black kale — flat blue-green crinkled leaves, includes Lacinato and dinosaur kale, red kale — frilly leaves with red or purple stems.
Kale has aged well. In its youth, some 4,000 years ago, kale grew wildly in the Mediterranean region before being cultivated by Greeks, Romans, and Europeans, who brought it to the Americas in the 16th century. It built a reputation as a hardy, easy to grow cold weather crop, until it gradually lost its following. Eventually, kale was grown ornamentally, a well-known salad bar garnish. No longer content as just a pretty face, kale is now recognized as a nutritional powerhouse, the epitome of "clean eating" in the form of kale chips, green smoothie and juice bar star, farmers' market standard, and has even massaged itself onto white tablecloth restaurant menus.
Kale (Brassica oleracea acephala) is part of the cruciferous family along with cabbage, broccoli, cauliflower and Brussels sprouts. Non-heading primitive cabbages, kale and collards share the same botanical name, differing mainly in the forms of their leaves. A one-cup serving packs 684 percent DV (Daily Value, based on 2,000 calories/day) of bone healthy vitamin K, 206 percent DV of eye protecting vitamin A, and kale is rich in antioxidant carotenoids lutein and zeaxanthin, compounds known to support eye health.
Foods rich in lutein and zeaxanthin, such as kale and other leafy greens, are known for their importance in eye health, including the prevention of age-related macular degeneration. In addition, these foods may also impact brain health and cognition in older adults (Nutrients, 2018). As a cruciferous vegetable, kale contains sulforaphane, which plays a powerful role in protection against certain types of cancer, and it may also decrease risk of cardiovascular disease and help in autism and osteoporosis (Journal of Medicinal Food, 2018).
The finer points
Choose kale with the deepest green leaves, avoiding browned or yellowed leaves, which mean tough, old and less flavorful. Remove leaves and wash them under running water. Pull the leaves off of the stem, and save stems for other uses like pesto or stock. Washed kale will store up to a week in the refrigerator. Be sure to massage kale using your hands after adding a simple olive oil, lemon juice or vinegar, and salt — this makes it softer to eat and enjoy. If cooking, steaming kale will maintain the most nutrients. Use raw kale in salads and smoothies, or cooked in frittatas, soups, or sauteed with other vegetables as a tasty side.
(Reprinted with permission from Environmental Nutrition, a monthly publication of Belvoir Media Group, LLC. 800-829-5384. www.EnvironmentalNutrition.com.)