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Kale is a member of the cabbage (Brassica) family and is often labeled a superfood because it is so high in nutrients per calorie.1 Kale is also low in fat and high in fiber, making it a great addition to almost any diet for the substantial nutritional and health benefits it provides.

Different varieties of kale provide different eating experiences. Some are more pungent, for instance, while others have a fairly mellow flavor. This enables you to choose the variety that you enjoy most.

Kale Nutrition Facts

One cup of raw kale (20.6g) provides 7.2 calories, 0.6g of protein, 0.9g of carbohydrates, and 0.3g of fat. Kale is a great source of vitamins A, K, and C, as well as potassium and calcium. The following nutrition information is provided by the U.S. Department of Agriculture (USDA).2

Carbs

One cup of raw kale contains less than a gram of carbohydrate. Most of this carbohydrate is in the form of fiber (0.8 of the 0.9 total grams). The remainder consists of a small amount of naturally occurring sugars.

The glycemic load of kale is estimated to be 3, making it a low-glycemic food.3 Glycemic load indicates a food's impact on blood sugar and, unlike the glycemic index, takes portion size into account when estimating this effect.

Fats

There is almost no fat in kale. However, the way that you prepare this green superfood may change the nutrition it provides. If you cook kale in butter or oil, for instance, or rub olive oil on the leaves before roasting them or adding them to a salad, there will be additional fat.

Protein

Kale provides less than 1 gram of protein per one-cup serving. The protein it does contain is easily digestible.4

Vitamin and Minerals

Kale is an excellent source of vitamin K, vitamin A, and vitamin C. As a plant-based source of calcium, it is a favorable addition to vegetarian and vegan meal plans.5 Kale also provides a good amount of potassium, along with trace amounts of manganese, copper, and some B vitamins.

Calories

One cup of raw kale contains only 7.2 calories. When compared to other leafy greens, kale has slightly fewer calories than a cup of shredded iceberg lettuce (10 calories)6 and slightly more calories than a cup of spinach (6.7 calories).7

Health Benefits

Kale packs a huge nutritional punch. Comparable salad greens—like romaine, iceberg lettuce, and mesclun or spring mixes—don't provide the same level of nutrition as kale. The nutrients in kale can be beneficial to your health.

Assists in Healthy Weight Maintenance

Kale and other dark green vegetables provide great nutritional benefits for very few calories. The fiber and protein in kale can also help you to feel full and satisfied after eating. Studies show that diets higher in vegetables are associated with greater weight loss.8

Promotes Better Heart Health

A large research review published in the journal Nutrients compared the health benefits of different vegetables. Kale was categorized with other cruciferous vegetables like broccoli and cauliflower. Study authors reported that, along with leafy greens, this category of veggies may provide the greatest cardiovascular health benefits.9

Reduces Risk of Cancer

Kale is one of the cruciferous vegetables shown to have anti-cancer properties. Kale contains glucosinolates , which are compounds being researched for their potential ability to manage certain health conditions in humans, including certain types of cancer.10

Improves Bone Health

Vitamin K is important for bone health, as well as for clotting blood.11 Vitamin K deficiency is associated with osteoporosis; studies have shown that supplementation has a positive effect on the bone health of postmenopausal women.12

While taking a dietary supplement may be beneficial, including foods with vitamin K (and other nutrients, like calcium) can help ensure that you are not deficient in this important nutrient.

Aids in Cell Protection and Repair

Kale provides over 20% of your daily vitamin C needs in a one-cup serving. Vitamin C is a water-soluble vitamin that is important for boosting immunity, repairing cells, and slowing the aging process.13

As an antioxidant, vitamin C is believed to prevent oxidative stress caused by exposure to free radicals. Experts recommend consuming antioxidants through foods such as fruits and vegetables, rather than taking an antioxidant supplement.14

Allergies

Kale allergies are rare. Individuals with pollen-food allergy syndrome may have a reaction to kale, especially when it is consumed raw.15 If you suspect that you may be allergic to kale, speak to your doctor or allergist.

Adding kale to your diet may even help with other allergies. One study found that after eating kale for 12 weeks, 120 subjects with allergies to mites or house dust had fewer symptoms (such as nasal discharge) and reported an improvement in daily living.16

Adverse Effects

If you take a blood thinner like warfarin, it is important to be consistent with your vitamin K intake.17 Since kale is high in vitamin K, working with your healthcare provider or a registered dietitian can make sure your intake is consistent from day to day.

Varieties

When shopping for kale, you might notice different types available. Many are green, but there are also red and purple varieties. Each variety differs in texture, taste, and appearance.

• Curly kale is usually deep green in color with ruffled leaves and has a pungent, bitter, peppery flavor.
• Ornamental kale, often referred to as salad savoy, can be either green, white, or purple and has a more mellow flavor.
• Dinosaur kale, or Tuscan kale, has a sweeter taste and a more delicate texture than curly kale and is often a blue-green color. 
• Baby kale is readily available and has smaller, softer leaves that many people find more palatable than the larger ones.

Nutritionally, the various varieties are similar. Each contains a host of vitamins, minerals, and antioxidants. Purple varieties contain anthocyanins, which have been linked to improved heart health.18

When It’s Best

Kale is typically available all year long, with its peak season during the winter months. When buying it fresh, look for kale that is crisp with a grayish-green color. Avoid kale that is wilted or limp.

If fresh kale is intimidating, you can either purchase kale that has already been cleaned and cut (this is good for making kale chips or to throw in soups, stews, or chili) or you can purchase frozen chopped kale.

Many times, buying frozen vegetables is just as good if not better than buying fresh. The vegetables are picked at their peak freshness, which makes them retain more vitamins and minerals,19 and you don't have to worry about it spoiling.

Storage and Food Safety

You can store kale in the coldest part of your refrigerator for a few days. To prevent wilting, place it in a plastic bag first and close it loosely. If you are unable to use it in a few days, cook it and place it back in the refrigerator cooked.

Freeze your kale if you don't plan on using it for a while. It will keep in the freezer for about a month or two.

Always be sure to wash kale before using it because the large curly leaves often catch dirt. To wash fresh kale, place it in a bowl of cold water and swish it around. Empty the bowl and repeat until all the dirt is cleared from the leaves.

How to Prepare

Kale has a bitter flavor and pairs well with rich, flavored meats such as pork. It can be steamed, sautéed, boiled, or chopped and used raw in salads. For a healthy chip alternative, try baking the leaves to turn them into crispy kale chips.

You can also use kale in soups, stews, egg dishes, and chili. It has a great way of enhancing the flavor of your meals and serves as a hearty and healthy addition to your menu plan.

Some experts suggest steaming kale to maximize its cholesterol-lowering effects. Its fiber-related components do a better job of binding with the bile acids in your digestive tract when they've been steamed.

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