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Part 2 of the article from WHFoods!

Description

The beautiful leaves of the kale plant provide an earthy flavor and more nutritional value for fewer calories than almost any other food around. Although it can be found in markets throughout the year, it is in season from the middle of winter through the beginning of spring when it has a sweeter taste and is more widely available.

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 phytonutrients. It is easy to grow and can grow in colder temperatures where a light frost will produce especially sweet kale leaves. There are several varieties of kale; these include curly kale, ornamental kale, and dinosaur (or Lacinato or Tuscan) 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 or Tuscan kale. It features dark blue-green leaves that have an embossed texture. It has a slightly sweeter and more delicate taste than curly kale.

History

Like broccoli, cauliflower, and collards, kale is a descendent of the wild cabbage, a plant thought to have originated in Asia Minor and to have been brought to Europe around 600 B.C. by groups of Celtic wanderers. Curly kale played an important role in early European foodways, having been a significant crop during ancient Roman times and a popular vegetable eaten by peasants in the Middle Ages. English settlers brought kale to the United States in the 17th century.

Both ornamental and dinosaur kale are much more recent varieties. Dinosaur kale was discovered in Italy in the late 19th century. Ornamental kale, originally a decorative garden plant, was first cultivated commercially as in the 1980s in California. Ornamental kale is now better known by the name salad savoy.

How to Select and Store

Look for kale with firm, deeply colored leaves and moist hardy stems. Kale should be displayed in a cool environment since warm temperatures will cause it to wilt and will negatively affect its flavor. The leaves should look fresh, be unwilted, and be free from signs of browning, yellowing, and small holes. Choose kale with smaller-sized leaves since these will be more tender and have a more mild flavor than those with larger leaves. Kale is available throughout the year, although it is more widely available, and at its peak, from the middle of winter through the beginning of spring.

To store, place kale in a plastic storage bag removing as much of the air from the bag as possible. Store in the refrigerator where it will keep for 5 days. The longer it is stored, the more bitter its flavor becomes. Do not wash kale before storing because exposure to water encourages spoilage.

How to Enjoy

A Few Quick Serving Ideas

  • Braise chopped kale and apples. Before serving, sprinkle with balsamic vinegar and chopped walnuts.
  • Combine chopped kale, pine nuts, and feta cheese with whole grain pasta drizzled with olive oil.

Safety

Kale and Oxalates

Kale is among a small number of foods that contain measurable amounts of oxalates, naturally occurring substances found in plants, animals, and human beings. When oxalates become too concentrated in body fluids, they can crystallize and cause health problems. For this reason, individuals with already existing and untreated kidney or gallbladder problems may want to avoid eating kale. Laboratory studies have shown that oxalates may also interfere with absorption of calcium from the body. Yet, in every peer-reviewed research study we’ve seen, the ability of oxalates to lower calcium absorption is relatively small and definitely does not outweigh the ability of oxalate-containing foods to contribute calcium to the meal plan. If your digestive tract is healthy, and you do a good job of chewing and relaxing while you enjoy your meals, you will get significant benefits — including absorption of calcium – from calcium-rich foods plant foods that also contain oxalic acid. Ordinarily, a healthcare practitioner would not discourage a person focused on ensuring that they are meeting their calcium requirements from eating these nutrient-rich foods because of their oxalate content.

Kale and Pesticide Residues

According to the Environmental Working Group (EWG) in their 2012 report, Shopper’s Guide to Pesticides in Produce, conventionally grown kale are contaminated with concentrations of organophosphate insecticides, which are considered to be highly toxic to the nervous system. While they were not among the 12 varieties of produce most concentrated in overall pesticide residues (and therefore not part of the EWG’s traditional “Dirty Dozen”), the EWG felt that this organophosphate concentration was relevant enough to bring attention to kale. They actually renamed their produce category of concern from “Dirty Dozen” to “Dirty Dozen Plus” with kale and collard greens being the “Plus” conventionally grown produce. Therefore, individuals wanting to avoid pesticide-associated health risks may want to avoid consumption of kale unless it is grown organically.

Kale as a “Goitrogenic” Food

Kale is sometimes referred to as a “goitrogenic” food. Yet, contrary to popular belief, according to the latest studies, foods themselves — kale included — are not “goitrogenic” in the sense of causing goiter whenever they are consumed, or even when they are consumed in excess. In fact, most foods that are commonly called “goitrogenic” — such as the cruciferous vegetables (including kale, broccoli, and cauliflower) and soyfoods — do not interfere with thyroid function in healthy persons even when they are consumed on a daily basis. Nor is it scientifically correct to say that foods “contain goitrogens,” at least not if you are thinking about goitrogens as a category of substances like proteins, carbohydrates, or vitamins. With respect to the health of our thyroid gland, all that can be contained in a food are nutrients that provide us with a variety of health benefits but which, under certain circumstances, can also interfere with thyroid function. The term “goitrogenic food” makes it sound as if something is wrong with the food, but that is simply not the case. What causes problems for certain individuals is not the food itself but the mismatched nature of certain substances within the food to their unique health circumstances.

Nutritional Profile

Introduction to Food Rating System Chart

The following chart shows the nutrients for which this food is either an excellent, very good or good source. Next to the nutrient name you will find the following information: the amount of the nutrient that is included in the noted serving of this food; the %Daily Value (DV) that that amount represents (similar to other information presented in the website, this DV is calculated for 25-50 year old healthy woman); the nutrient density rating; and, the food’s World’s Healthiest Foods Rating. Underneath the chart is a table that summarizes how the ratings were devised. 

Kale
1.00 cup cooked
130.00 grams
36.40 calories
Nutrient Amount DV
(%)
Nutrient
Density
World’s Healthiest
Foods Rating
vitamin K 1062.10 mcg 1327.6 656.5 excellent
vitamin A 17707.30 IU 354.1 175.1 excellent
vitamin C 53.30 mg 88.8 43.9 excellent
manganese 0.54 mg 27.0 13.4 excellent
fiber 2.60 g 10.4 5.1 very good
copper 0.20 mg 10.0 4.9 very good
tryptophan 0.03 g 9.4 4.6 very good
calcium 93.60 mg 9.4 4.6 very good
vitamin B6 0.18 mg 9.0 4.5 very good
potassium 296.40 mg 8.5 4.2 very good
iron 1.17 mg 6.5 3.2 good
magnesium 23.40 mg 5.8 2.9 good
vitamin E 1.11 mg 5.6 2.7 good
omega-3 fats 0.13 g 5.4 2.7 good
vitamin B2 0.09 mg 5.3 2.6 good
protein 2.47 g 4.9 2.4 good
vitamin B1 0.07 mg 4.7 2.3 good
folate 16.90 mcg 4.2 2.1 good
phosphorus 36.40 mg 3.6 1.8 good
vitamin B3 0.65 mg 3.2 1.6 good
World’s Healthiest
Foods Rating
Rule
excellent DV>=75% OR
Density>=7.6 AND DV>=10%
very good DV>=50% OR
Density>=3.4 AND DV>=5%
good DV>=25% OR
Density>=1.5 AND DV>=2.5%

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