Nutritionally rated, kale is near the top amongst vegetables.
- A one cup serving of kale contains only 36 calories.
- Organosulfur Compounds that Prevent Cancer
- Carotenoids that Lower Cataract Risk
- Kale Gets an A+ for its Pro-vitamin A
- Protection against Emphysema
- A Healthy Dose of Vitamin C for Antioxidant Protection and Immune Support
- Protection against Rheumatoid Arthritis
- Manganese – Energy Production Plus Antioxidant Protection
- Cardiovascular Protection Brought to You By Kale’s Vitamin B6 and Riboflavin
- A Very Good Source of Fiber, tryptophan, calcium, potassium, Vitamin B1 (thiamin)., Vitamin B2 (riboflavin), Vitamin B3 (niacin), Vitamin E, magnesium, iron, copper, folate and zinc.
- Calcium – For A Lot Less Calories and Minus the Fat in Cow’s Milk
As a member of the Brassica genus of foods, kale stands out as an anticancer food. It is high is sulforaphane, which stimulates the body to produce cancer-fighting enzymes. Glucosinolates, (sulfur compounds) which are found in large amounts in cruciferous vegetables such as kale, are broken down into further compounds named isothiocyanates and indoles when the vegetable is cut or chewed. Researchers have proven that the ability of kale’s Glucosinolates and cysteine sulfoxides activates the detoxification of enzymes in the liver which help neutralize potentially carcinogenic substances. These detoxifying enzymes include quinine reductases and glutathione-S-tranferases. Have shown the protective effect of these two nutrients against the risk of cataracts.
Kale is also an excellent source of Vitamin C. Vitamin C prevents the free radical damage which triggers the inflammatory cascade, and is therefore associated with reduced severity of inflammatory conditions such as asthma, osteoarthritis, and rheumatoid arthritis. Vitamin C also prevents the free radical damage which can oxidize cholesterol. Once oxidized, cholesterol begins sticking to artery walls, building up plaque that may eventually grow large enough to impede blood flow, or rupture to cause a heart attack or stroke. With Vitamin C’s ability to neutralize free radicals, it can help prevent this oxidation of cholesterol. Vitamin C is also crucial for the proper function of a healthy immune system. Thus, it has been shown to improve cold symptoms and may be helpful in preventing recurring ear infections.
Kale is also well known for it’s presence of carotenoids, especially lutein and zeaxanthin. These two substances act as a filter and help to protect the eye from overexposure to ultraviolet light. Kale is a leafy green vegetable that belongs to the Brassica family, a group of vegetables including cabbage, collards and Brussels sprouts that have gained recent widespread attention due to their health-promoting, sulfur-containing phytochemicals. There are several varieties of kale known commonly as curly kale, ornamental kale and dinosaur kale, all of which differ in taste, texture and appearance. The scientific name for kale is Brassica oleracea. Curly kale has ruffled leaves and a fibrous stalk and is usually deep green in color. It has a lively pungent flavor with delicious bitter peppery qualities.
Ornamental kale is a more recently cultivated species that is oftentimes referred to as salad savoy. Its leaves may either be green, white or purple and its stalks coalesce to form a loosely knit head. Ornamental kale has a more mellow flavor and tender texture. Dinosaur kale is the common name for the kale variety known as Lacinato. It features dark blue-green leaves that have an embossed texture. It has a slightly sweeter and more delicate taste than curly kale. Kale and collards are similar in many respects, differing in little more than the forms of their leaves. They are, in effect, primitive cabbages that have been retained through thousands of years. Although more highly developed forms, such as cauliflower, broccoli, and head cabbage, have been produced in the last two thousand years or so, the kales and collards have persisted, although primitive, because of their merits as garden vegetables.
These leafy non-heading cabbages bear the Latin name Brassica oleracea variety acephala, the last term meaning “without a head.” They have many names in many languages, as a result of their great antiquity and widespread use. “Collards” is a corruption of coleworts or colewyrts, Anglo-Saxon terms literally meaning “cabbage plants.” The cabbage-like plants are native to the eastern Mediterranean or to Asia Minor. They have been in cultivation for so long, and have been so shifted about by prehistoric traders and migrating tribes, that it is not certain which of those two regions is the origin of the species. The original “cabbage” was undoubtedly a non-heading kind with a prominent stalk or stem, and the kales and collards are not far removed from it. Wild forms have become widely distributed from their place of origin and are found on the coasts of northern Europe and Britain.
Kale – Known Since Antiquity
Apparently none of the several principal forms of kale and collards that we know today are new. All have been known for at least two thousand years. The Greeks grew kale and collards, although they made no such distinction between them as we make today. Well before the Christian era the Romans grew several kinds, including those with large leaves and stalks and a mild flavor; a crisp-leaved form; some with small stalks and small, sharp-tasting leaves; a broad-leaved form like collards; and others with curled leaves and a fine flavor. Bible or from Egyptian hieroglyphs, kale is one of the oldest cultivated and most venerable forms of vegetables. Like broccoli, cauliflower and collards, kale is a descendant of the wild cabbage. It originated as a food crop in the Eastern Mediterranean and Asia Minor over 4,000 years ago. Theophrastus described a form of Kale in 350 BC and travelers then introduced the hearty vegetable down through the ages to many other parts of the world.
Kale was a significant crop during ancient Roman times and was very popular among peasants during the Middle Ages. It was finally brought to North America by European settlers in the 17th Century. Dinosaur kale was discovered in Italy during the late 19th Century. It features dark blue-green leaves with leaves that have an embossed texture. It is slightly sweeter and has a more delicate taste than curly kale. Curly kale has ruffled leaves and is usually deep green in color. Its flavor is a bit pungent with bitter peppery qualities. Decorative Kale, originally used as a decorative garden plant, was first cultivated commercially in the 1980’s in California. Although used in the United States primarily as a decoration in salad bars, more and more people are becoming aware of it’s rich nutrient values and great taste. Ornamental kale is now becoming better known by the name salad Savoy
Kale – Rich in Minerals and Vitamins
Those who know both kale and collards usually consider the latter to have the better eating quality. Nutrition experts in recent years have sought to popularize both plants because they are unusually rich in the minerals and vitamins provided by green leafy foods. Before the “newer knowledge” of nutrition, our experts bemoaned the poor diet of southern farmers, especially the Negroes, and were amazed to find so many of those people to be apparently well nourished. The ubiquitous collard patch on every farm, and in nearly every dooryard where there is room, is now believed to play a most important part in furnishing the necessary vitamins and minerals. On one truck farm I saw a beautiful 10 acre field of collards.
The farmer explained it was not for sale, but “just a collard patch for the hired hands.” All varieties of collards appear rather similar, but the kales show interesting diversity: tall and short; highly curled and plain leaved; blue-green, yellow-green, and red; erect and flat-growing; in various combinations and gradations of these characters. Until the last few years kale and collards were marketed only in the natural state. Now, however, several enterprising American canners are preserving them in tin, especially in a finely chopped or “sieved” form as food for babies or persons requiring a special diet. Kale and collards are among the easiest of all vegetables to grow. They are biennials, putting up their flower or seed stalks in the spring of their second season of growth.
Phytonutrients, Indoles, Sulfurophanes, Carotenes, Chlorophyll, Vitamins & Minerals. Sulfur-based phytonutrients and others lower risk of cancer and benefit nearly every body system. Kale is full of nutrients. It’s a popular ingredient of green vegetable juice extract. Kale contains 181 mg of calcium per 100 grams (milk contains 100 mg of calcium per 100 grams), that helps strengthen bones. And with half the iron of beef liver, kale supports memory improvement. Kale provides fiber and a variety of vitamins, including vitamin C, to help prevent digestive disorders.
Kale Health Benefits
Organosulfur Compounds that Prevent Cancer
As a member of the Brassica genus of foods, kale stands out as an anticancer food. It’s the organosulfur compounds in this food that have been main subject of phytonutrient research, and these include the glucosinolates and the methyl cysteine sulfoxides. Although there are over 100 different glucosinolates in plants, only 10-15 are present in kale and other Brassicas. Yet these 10-15 glucosinolates appear able to lessen the occurrence of a wide variety of cancers, including breast and ovarian cancers. Exactly how kale’s sulfur-containing phytonutrients prevent cancer is not clear, but several researchers point to the ability of its glucosinolates and cysteine sulfoxides to activate detoxifying enzymes in the liver that help neutralize potentially carcinogenic substances.
(These detoxifying enzymes include quinone reductases and glutathione-S-transferases). For example, scientists have found that sulforaphane, a potent glucosinolate phytonutrient found in kale and other Brassica vegetables, boosts the body’s detoxification enzymes, potentially by altering gene expression, thus helping to clear potentially carcinogenic substances more quickly. Sulforaphane, which is formed when cruciferous vegetables such as kale are chopped or chewed, not only triggers the liver to produce enzymes that detoxify cancer-causing chemicals, inhibits chemically-induced breast cancers in animal studies, and induces colon cancer cells to commit suicide, but now, a new study published in the September 2004 issue of the Journal of Nutrition shows sulforaphane helps stop the proliferation of breast cancer cells, even in the later stages of their growth. (October 19, 2004)
Carotenoids that Lower Cataract Risk
In addition to its unique organosulfur compounds, kale is well-known for its carotenoids, especially lutein and zeaxanthin. These carotenoids act like sunglass filters and prevent damage to the eyes from excessive exposure to ultraviolet light. Studies have shown the protective effect of these nutrients against the risk of cataracts, where increased eye cloudiness leads to blurred vision. In one study, people who had a diet history of eating lutein-rich foods like kale had a 50% lower risk for new cataracts. Kale also emerged from our food ranking system as an excellent source of traditional nutrients, including vitamin A, vitamin C, vitamin B6 and manganese. It is also a very good source of dietary fiber, calcium, copper, iron, vitamin B1, vitamin B2 and vitamin E. This combination of vitamins, minerals, and phytonutrients makes kale a health superstar!
Kale Gets an A+ for its Pro-vitamin A
Our food ranking system qualified kale as an excellent source of vitamin A on account of its concentrated beta-carotene content. Once inside the body, beta-carotene can be converted into vitamin A, so when you eat kale, it’s like getting both these beneficial nutrients at once. One cup of kale contains just 36.4 calories, but provides 192.4% of the daily value for vitamin A. Both vitamin A and beta-carotene are important vision nutrients. In a study of over 50,000 women nurses aged 45 to 67, women who consumed the highest dietary amount of vitamin A had a 39% reduced risk of developing cataracts. Beta-carotene has also been the subject of extensive research in relationship to cancer prevention and prevention of oxygen-based damage to cells.
Beta-carotene may help to protect against certain forms of cancer since it belongs to the family of phytochemicals known as carotenoids. In population studies, consuming foods high in carotenoids is consistently found to be associated with a lower risk for various epithelial cancers. (The epithelium includes the cells that cover the entire surface of the body and line most of the internal organs.) In one study of 176 Australian men, researchers examined the diets of 88 of whom were treated for skin cancer and 88 men without cancer. The researchers found that men who ate more foods rich in beta-carotene, like kale, had a statistically lower risk of developing skin cancer.
Protection against Emphysema
If you or someone you love is a smoker, or if you are frequently exposed to secondhand smoke, then making vitamin A-rich foods, such as kale, part of your healthy way of eating may save your life, suggests research conducted at Kansas State University. While studying the relationship between vitamin A, lung inflammation, and emphysema, Richard Baybutt, associate professor of nutrition at Kansas State, made a surprising discovery: a common carcinogen in cigarette smoke, benzo(a)pyrene, induces vitamin A deficiency. Baybutt’s earlier research had shown that rats fed a vitamin A-deficient diet developed emphysema. His latest animal studies indicate that not only does the benzo(a)pyrene in cigarette smoke cause vitamin A deficiency, but that a diet rich in vitamin A can help counter this effect, thus greatly reducing emphysema.
In his initial research, Baybutt took just weaned male rats and divided them into two groups, one of which was exposed to cigarette smoke, and the other to air. In the rats exposed to cigarette smoke, levels of vitamin A dropped significantly in direct correlation with their development of emphysema. In the second study, both groups of rats were exposed to cigarette smoke, but one group was given a diet rich in vitamin A. Among those rats receiving the vitamin A-rich foods, emphysema was effectively reduced.
Baybutt believes vitamin A’s protective effects may help explain why some smokers do not develop emphysema. “There are a lot of people who live to be 90 years old and are smokers,” he said. “Why? Probably because of their diet – The implications are that those who start smoking at an early age are more likely to become vitamin A deficient and develop complications associated with cancer and emphysema. And if they have a poor diet, forget it.” If you or someone you love smokes, or if your work necessitates exposure to second hand smoke, protect yourself by making sure that at least one of the World’s Healthiest Foods that are rich in vitamin A, such as kale, is a daily part of your healthy way of eating.(October 21, 2004)
A Healthy Dose of Vitamin C for Antioxidant Protection and Immune Support
Kale is an excellent source of vitamin C – just one cup of this cooked vegetable supplies 88.8% of the daily value for vitamin C. Vitamin C is the primary water-soluble antioxidant in the body, disarming free radicals and preventing damage in the aqueous environment both inside and outside cells. Inside cells, a potential result of free radical damage to DNA is cancer. Especially in areas of the body where cellular turnover is especially rapid, such as the digestive system, preventing DNA mutations translates into preventing cancer. This is why a good intake of vitamin C is associated with a reduced risk of colon cancer.
Free radical damage to other cellular structures and other molecules can result in painful inflammation, as the body tries to clear out the damaged parts. Vitamin C, which prevents the free radical damage that triggers the inflammatory cascade, is thus also associated with reduced severity of inflammatory conditions, such as asthma, osteoarthritis, and rheumatoid arthritis. Free radicals also oxidize cholesterol. Only after being oxidized does cholesterol stick to artery walls, building up in plaques that may eventually grow large enough to impede or fully block blood flow, or rupture to cause a heart attack or stroke. Since vitamin C can neutralize free radicals, it can help prevent the oxidation of cholesterol. Vitamin C, which is also vital for the proper function of a healthy immune system, is good for preventing colds and may be helpful in preventing recurrent ear infections.
Protection against Rheumatoid Arthritis
While one July 2004 study suggests that high doses of supplemental vitamin C makes osteoarthritis, a type of degenerative arthritis that occurs with aging, worse in guinea pigs, another indicates that vitamin C-rich foods, such as kale, provide humans with protection against inflammatory polyarthritis, a form of rheumatoid arthritis involving two or more joints. The findings, presented in the Annals of the Rheumatic Diseases were drawn from a study of more than 20,000 subjects who kept diet diaries and were arthritis-free when the study began, and focused on 73 subjects who developed inflammatory polyarthritis and 146 similar subjects who remained arthritis-free during follow-up between 1993 and 2001. Subjects who consumed the lowest amounts of vitamin C-rich foods were more than three times more likely to develop arthritis than those who consumed the highest amounts. (August 1, 2004)
Manganese – Energy Production Plus Antioxidant Protection
That same cup of kale will also provide you with 27.0% of the day’s needs for manganese. This trace mineral helps produce energy from protein and carbohydrates, and is involved in the synthesis of fatty acids that are important for a healthy nervous system and in the production of cholesterol that is used by the body to produce sex hormones. Manganese is also a critical component of an important antioxidant enzyme called superoxide dismutase. Superoxide dismutase (SOD) is found exclusively inside the body’s mitochondria (the oxygen-based energy factories inside most of our cells) where it provides protection against damage from the free radicals produced during energy production.
Cardiovascular Protection Brought to You By Kale’s Vitamin B6 and Riboflavin
Vitamin B6 is involved in an important cellular process called methylation at the juncture where homocysteine, a dangerous molecule that can directly damage blood vessel walls, is converted into a helpful amino acid, methionine. Without riboflavin’s assistance, however, vitamin B6 cannot change into the active form in which it catalyzes this conversion. No problem when kale is on the menu as it supplies both nutrients. A cofactor in the reaction that regenerates glutathione, riboflavin is required to help maintain adequate levels of one of the body’s most important antioxidants. Among glutathione’s many beneficial activities, it protects lipids like cholesterol from free radical attack. Only after it has been damaged by free radicals does cholesterol pose a threat to blood vessel walls. A cup of kale contains 9.0% of the daily value for vitamin B6 along with 5.3% of the daily value for riboflavin.
A Very Good Source of Fiber
Kale’s health benefits continue with its fiber; a cup of kale provides 10.4% of the daily value for fiber, which has been shown to reduce high cholesterol levels thus helping to prevent atherosclerosis. Fiber can also help out by keeping blood sugar levels under control, so kale is an excellent vegetable for people with diabetes. Kale’s fiber binds to cancer-causing chemicals, keeping them away from the cells lining the colon, providing yet another line of protection from colon cancer. And the fiber in kale can help reduce the uncomfortable constipation or diarrhea in those suffering from irritable bowel syndrome.
Calcium – For A Lot Less Calories and Minus the Fat in Cow’s Milk
Kale is also very good source of calcium. Calcium is one of the nutrients needed to make healthy bones, and dairy products are a heavily promoted source of this nutrient. But unlike dairy products, kale is not a highly allergenic food, nor does it contain any saturated fat – plus, a cup of kale supplies 93.6 mg of calcium (9.4% of the daily value for this mineral) for only 36.4 calories. In contrast, a cup of 2% cow’s milk provides 296.7 mg of calcium, but the cost is high: 121.2 calories and 14.6% of the day’s suggested limit on saturated fat.
Classification: Magnoliophyta, Magnoliopsida, Capparales, Cruciferae