Kale NutritionKale is an excellent source of vitamins A, C and K, and a good source of calcium, iron, magnesium, potassium and vitamin C, while being low in sodium. Kale is low in calories too; one cup of chopped kale has 34 calories and a little over one gram of fiber.
Kale also contains large amounts of phytochemicals. Lutein and zeaxanthin are related to vitamin A and may help lower your risk of developing cataracts and macular degeneration, and lutein may help prevent atherosclerosis. Kale, along with the other cruciferous vegetables, contain bitter substances called glucosinolates, some of which may have health benefits.
Studies on large populations of subjects suggest that eating cruciferous vegetables may help to prevent some forms of cancer, although the results are not conclusive. It's difficult to determine if specific foods truly prevent (or cause) cancer and other diseases because there are so many potential confounding factors. For example, people who eat more cruciferous vegetables may also eat more vegetables in general or be more health-conscious. However, lab studies may help us understand how sulforaphane may help to prevent cancer.
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. Sulforaphane may reduce your risk of some cancers by detoxifying carcinogens (substances that cause cancer) and by increasing the activity of antioxidants. Sulphorane may also have a direct effect on cancer cells themselves (at least it does in lab studies).
Choosing and Preparing KaleYou'll find kale in the produce section of your grocery store. Look for dark green bunches of leaves that are crisp and not wilted. You can freeze kale or store it in the refrigerator in a covered container.
Kale can be served raw, but it is usually cooked to reduce the bitterness and tenderize the leaves. For raw kale, rinse the kale and remove the stems. Slice the leaves into strips and use in salads. Kale can be chopped and boiled or steamed or used as an ingredient in a hearty soup or stew. You can also make dehydrated or baked Kale chips, which make a nutritious snack that is low in calories.
Healthy Kale Recipes
- Raw Kale Salad with Cranberries, Citrus, and Red Onion
- Kale Pesto
- Collard Greens and Kale
- Crispy Kale
- Kale and White Bean Soup With Spicy Sausage
Giovannucci E, Rimm EB, Liu Y, Stampfer MJ, Willett WC. "A prospective study of cruciferous vegetables and prostate cancer." Cancer Epidemiol Biomarkers Prev. 2003 Dec;12(12):1403-9.
Herr I, Baachler MW. "Dietary constituents of broccoli and other cruciferous vegetables: implications for prevention and therapy of cancer." Cancer Treat Rev. 2010 Aug;36(5):377-83.
Larsson SC, Haakansson N, Naaslund I, Bergkvist L, Wolk A. "Fruit and vegetable consumption in relation to pancreatic cancer risk: a prospective study." Cancer Epidemiol Biomarkers Prev. 2006 Feb;15(2):301-5.
United States Department of Agriculture, National Nutrient Database for Standard Refrence. "Kale, raw." Accessed March 6, 2011. http://www.nal.usda.gov/fnic/foodcomp/search/.
Voorrips LE, Goldbohm RA, van Poppel G, Sturmans F, Hermus RJ, van den Brandt PA. "Vegetable and fruit consumption and risks of colon and rectal cancer in a prospective cohort study: The Netherlands Cohort Study on Diet and Cancer." Am J Epidemiol. 2000 Dec 1;152(11):1081-92.