What's New and Beneficial About Collard Greens

• The cholesterol-lowering ability of collard greens may be the greatest of all commonly eaten cruciferous vegetables. In a recent study, steamed collard greens outshined steamed kale, mustard greens, broccoli, Brussels sprouts, and cabbage in terms of its ability to bind bile acids in the digestive tract. When this bile acid binding takes place, it is easier for the bile acids to be excreted from the body. Since bile acids are made from cholesterol, the net impact of this bile acid binding is a lowering of the body's cholesterol level. It's worth noting that steamed collards show much greater bile acid binding ability than raw collards.
• We get unique health benefits from collard greens in the form of cancer protection. The cancer-preventive properties of collard greens may be largely related to 4 specific glucosinolates found in this cruciferous vegetable: glucoraphanin, sinigrin, gluconasturtiian, and glucotropaeolin. Each of these glucosinolates can be converted into an isothiocyanate (ITC) that helps lower our cancer risk by supporting our detox and anti-inflammatory systems.

WHFoods Recommendations

You'll want to include collard greens as one of the cruciferous vegetables you eat on a regular basis if you want to receive the fantastic health benefits provided by the cruciferous vegetable family. At a minimum, include cruciferous vegetables as part of your diet 2-3 times per week, and make the serving size at least 1-1/2 cups. Even better from a health standpoint, enjoy collard greens and other vegetables from the cruciferous vegetable group 4-5 times per week, and increase your serving size to 2 cups.

It is very important not to overcook collard greens. Like other cruciferous vegetables overcooked collard greens will begin to emit the unpleasant sulfur smell associated with overcooking. To help collard greens to cook more quickly, evenly slice the leaves into 1/2-inch slices and the stems into 1/4-inch pieces. Let them sit for at least 5 minutes to bring out the health-promoting qualities and steam for 5 minutes. Serve with our Mediterranean Dressing. See 5-Minute Collard Greens.

This chart graphically details the %DV that a serving of Collard greens provides for each of the nutrients of which it is a good, very good, or excellent source according to our Food Rating System. Additional information about the amount of these nutrients provided by Collard greens can be found in the Food Rating System Chart. A link that takes you to the In-Depth Nutritional Profile for Collard greens, featuring information over 80 nutrients, can be found under the Food Rating System Chart.

• Health Benefits
• Description
• History
• How to Select and Store
• Tips for Preparing and Cooking
• How to Enjoy
• Individual Concerns
• Nutritional Profile
• References

Health Benefits

Unlike broccoli and kale and cabbage, you won't find many research studies devoted to the specific health benefits of collard greens. However, collard greens are sometimes included in a longer list of cruciferous vegetables that are lumped together and examined for the health benefits they provide. Based on a very small number of studies looking specifically at collard greens, and a larger number of studies looking at cruciferous vegetables as a group (and including collard greens on the list of vegetables studied), cancer prevention appears to be a standout area for collard greens with respect to their health benefits.

This connection between collard greens and cancer prevention should not be surprising since collard greens provide special nutrient support for three body systems that are closely connected with cancer development as well as cancer prevention. These three systems are (1) the body's detox system, (2) its antioxidant system, and (3) its inflammatory/anti-inflammatory system. Chronic imbalances in any of these three systems can increase risk of cancer, and when imbalances in all three systems occur simultaneously, the risk of cancer increases significantly. Among all types of cancer, prevention of the following cancer types is most closely associated with intake of collard greens: bladder cancer, breast cancer, colon cancer, lung cancer, prostate cancer, and ovarian cancer.

Detox Support Provided by Collard Greens

The detox support provided by collard greens includes antioxidant nutrients to boost Phase 1 detoxification activities and sulfur-containing nutrients to boost Phase 2 activities. Collard greens also contain phytonutrients called glucosinolates that can help activate detoxification enzymes and regulate their activity. Four key glucosinolates that have been clearly identified in collard greens in significant amounts are glucobrassicin, glucoraphanin, gluconasturtiian, and glucotropaeolin.

If we fail to give our body's detox system adequate nutritional support, yet continue to expose ourselves to unwanted toxins through our lifestyle and our dietary choices, we can place our bodies at increased risk of toxin-related damage that can eventually increase our cells' risk of becoming cancerous. That's one of the reasons it's so important to bring collard greens and other cruciferous vegetables into our diet on a regular basis.

The Antioxidant Benefits of Collard Greens

As an excellent source of vitamin C, vitamin A (in the form of carotenoids), and manganese, and a good source of vitamin E, collard greens provide us with 4 core conventional antioxidants. But the antioxidant support provided by collard greens extends far beyond the conventional nutrients into the realm of phytonutrients. Caffeic acid, ferulic acid, quercetin, and kaempferol are among the key antioxidant phytonutrients provided by collard greens. This broad spectrum antioxidant support helps lower the risk of oxidative stress in our cells. Chronic oxidative stress—meaning chronic presence over overly reactive oxygen-containing molecules and cumulative damage to our cells by these molecules—is a risk factor for development of most cancer types. By providing us with such a great array of antioxidant nutrients, collard greens help lower our cancer risk by helping us avoid chronic and unwanted oxidative stress.

Collard Greens' Anti-inflammatory Benefits

As an excellent source of vitamin K and a good source of omega-3 fatty acids (in the form of alpha-linolenic acid, or ALA), collard greens provide us with two hallmark anti-inflammatory nutrients. Vitamin K acts as a direct regulator of our inflammatory response, and ALA is the building block for several of the body's most widely-used families of anti-inflammatory messaging molecules. In addition to these two anti-inflammatory components, one of the glucosinolates found in collard greens—glucobrassicin—can be readily converted into an isothiocyanate molecule called I3C, or indole-3-carbinol (I3C). I3C is an anti-inflammatory compound that can actually operate at the genetic level, and by doing so, prevent the initiation of inflammatory responses at a very early stage.

Like chronic oxidative stress and chronic weakened detox ability, chronic unwanted inflammation can significantly increase our risk of cancers and other chronic diseases (especially cardiovascular diseases).

Collard Greens and Cardiovascular Support

Researchers have looked at a variety of cardiovascular problems—including heart attack, ischemic heart disease, and atherosclerosis—and found preliminary evidence of an ability on the part of cruciferous vegetables to lower our risk of these health problems. Yet regardless of the specific cardiovascular problem, it is one particular type of cardiovascular benefit that has most interested researchers, and that benefit is the anti-inflammatory nature of collard greens and their fellow cruciferous vegetables. Scientists have not always viewed cardiovascular problems as having a central inflammatory component, but the role of unwanted inflammation in creating problems for our blood vessels and circulation has become increasingly fundamental to an understanding of cardiovascular diseases. Of particular interest here has been the isothiocyanate (ITC) sulforaphane, which is made from glucoraphanin (a glucosinolate) found in collard greens. Not only does this ITC trigger anti-inflammatory activity in our cardiovascular system, it may also be able to help prevent and even possibly help reverse blood vessel damage.

A second area you can count on collard greens for cardiovascular support involves their cholesterol-lowering ability. Our liver uses cholesterol as a basic building block to product bile acids. Bile acids are specialized molecules that aid in the digestion and absorption of fat through a process called emulsification. These molecules are typically stored in fluid in our gall bladder, and when we eat a fat-containing meal, they get released into the intestine where they help ready the fat for interaction with enzymes and eventual absorption up into the body. When we eat collard greens, fiber-related nutrients in this cruciferous vegetable bind together with some of the bile acids in the intestine in such a way that they simply stay inside the intestine and pass out of our body in a bowel movement, rather than getting absorbed along with the fat they have emulsified. When this happens, our liver needs to replace the lost bile acids by drawing upon our existing supply of cholesterol, and as a result, our cholesterol level drops down. Collard greens provide us with this cholesterol-lowering benefit whether they are raw or cooked. However, a recent study has shown that the cholesterol-lowering ability of raw collard greens improves significantly when they are steamed. In fact, when the cholesterol-lowering ability of steamed collard greens was compared with the cholesterol-lowering ability of the prescription drug cholestyramine (a medication that is taken for the purpose of lowering cholesterol), collard greens bound 46% as many bile acids (based on a standard of comparison involving total dietary fiber).

In addition to the support factors described above, it would be wrong to talk about the cardiovascular benefits of collard greens without mentioning their diverse array of B vitamins. Collard greens are a very good source of vitamins B2, B6, and choline, and a good source of vitamins B1, B3, folate, and pantothenic acid. A well-balanced intake of B vitamins - especially vitamins B6, B12, folate, and choline - can be important in controlling cardiovascular disease risk. Since excessive or deficient intake of these B vitamins can have an unwanted impact on your disease risk, it is great to have a food like collard greens that provide a helpful amount of so many B vitamins.

Collard Greens and Digestive Support

The fiber content of collard greens—over 7 grams in every cup—makes this cruciferous vegetable a natural choice for digestive system support. Yet the fiber content of collard greens is only one of their digestive support mechanisms. Researchers have determined that the sulforaphane made from a glucosinolate in collard greens (glucoraphanin) helps protect the health of our stomach lining by preventing bacterial overgrowth of Helicobacter pylori in our stomach or too much clinging by this bacterium to our stomach wall.

Other Health Benefits From Collard Greens

The anti-inflammatory nature of glucosinolates/isothiocyanates and other nutrients found in collard greens has been the basis for new research on inflammation-related health problems and the potential role of collard greens in their prevention. Current and potentially promising research is underway to examine the benefits of collard greens in relationship to our risk of the following inflammation-related conditions: Crohn's disease, inflammatory bowel disease, insulin resistance, irritable bowel syndrome, metabolic syndrome, obesity, rheumatoid arthritis, type 2 diabetes, and ulcerative colitis.

Description

All cruciferous vegetables provide integrated nourishment across a wide variety of nutritional categories and provide broad support across a wide variety of body systems as well. For more on cruciferous vegetables see:

• Eating Healthy with Cruciferous Vegetables
• Feeling Great with Cruciferous Vegetables

Collards are leafy green vegetables that belong to the same family that includes cabbage, kale, and broccoli. While they share the same botanical name as kale, Brassica oleracea, and some resemblance, they have their own distinctive qualities. Like kale, collards are one of the non-head forming members of the Brassica family. Collards' unique appearance features dark blue green leaves that are smooth in texture and relatively broad. They lack the frilled edges that are so distinctive to their cousin kale.

Long a staple of the Southern United States, collard greens, unlike their cousins kale and mustard greens, have a very mild, almost smoky flavor. Although they are available year-round they are at their best from January through April.

History

Like kale, cauliflower and broccoli, collards are descendents of the wild cabbage, a plant thought to have been consumed as food since prehistoric times and to have originated in Asia Minor. From there it spread into Europe, being introduced by groups of Celtic wanderers around 600 B.C. Collards have been cultivated since the times of the ancient Greek and Roman civilizations. While collards may have been introduced into the United States before, the first mention of collard greens dates back to the late 17th century. Collards are an integral food in traditional southern American cuisine.

How to Select and Store

Look for collard greens that have firm, unwilted leaves that are vividly deep green in color with no signs of yellowing or browning. Leaves that are smaller in size will be more tender and have a milder flavor. They should be displayed in a chilled section in the refrigerator case to prevent them from wilting and becoming bitter.

Place collard greens in a plastic bag, removing as much of the air from the bag as possible. Store in the refrigerator where they should keep fresh for about three to five days.

Tips for Preparing and Cooking

Tips for Preparing Collard Greens

Rinse collard greens under cold running water. Chop leaf portion into 1/2-inch slices and the stems into 1/4-inch pieces for quick and even cooking.

To get the most health benefits from collard greens, we recommend letting them sit for a minimum of 5 minutes before cooking. Sprinkling with lemon juice before letting them sit may be able to help activate their myrosinase enzymes and increase formation of beneficial isothiocyanates in the greens.

The Healthiest Way of Cooking Collard Greens

We recommend Healthy Steaming collard greens for maximum nutrition and flavor. Fill the bottom of a steamer pot with 2 inches of water. While waiting for the water to come to a rapid boil chop greens. Steam for 5 minutes and toss with our Mediterranean Dressing and top with your favorite optional ingredients. For details see 5-Minute Collard Greens.

How to Enjoy

A Few Quick Serving Ideas

• Serve steamed collard greens with black-eyed peas and brown rice for a Southern-inspired meal.
• Use lightly steamed, cooled, and chopped collard greens as a filling in your sushi vegetable rolls.

WHFoods Recipes That Feature Collard Greens

• Poached Eggs Over Collard Greens & Shiitake Mushrooms
• Italian Navy Bean Soup with Rosemary
• Zesty Mexican Soup
• 5-Minute Collard Greens
• Pinto Beans with Collard Greens
• Steamed Vegetable Medley

Individual Concerns

Collard Greens and Pesticide Residues

According to the Environmental Working Group (EWG) in their 2016 report, Shopper's Guide to Pesticides in Produce, conventionally grown collard greens 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 collard greens. They actually renamed their produce category of concern from "Dirty Dozen" to "Dirty Dozen Plus" with leafy greens such as collard greens and kale (as well as hot peppers) being the "Plus" conventionally grown produce. Therefore, individuals wanting to avoid pesticide-associated health risks may want to avoid consumption of collard greens unless they are grown organically.

Collard Greens and Goitrogens

You may sometimes hear collard greens being described as a food that contains "goitrogens," or as a food that is "goitrogenic." For helpful information in this area—including our WHFoods Recommendations—please see our article What is meant by the term "goitrogen" and what is the connection between goitrogens, food, and health?.

Nutritional Profile

Collard greens are an excellent source of vitamin K, vitamin A (in the form of carotenoids), manganese, vitamin C, dietary fiber, and calcium.. In addition, collard greens are a very good source of vitamin B1, vitamin 6, and iron. They are also a good source of vitamin E, copper, protein, magnesium, phosphorus, vitamin B5, folate, omega-3 fatty acids, niacin, vitamin B1, and potassium.

For an in-depth nutritional profile click here: Collard greens.

In-Depth Nutritional Profile

In addition to the nutrients highlighted in our ratings chart, an in-depth nutritional profile for Collard greens is also available. This profile includes information on a full array of nutrients, including carbohydrates, sugar, soluble and insoluble fiber, sodium, vitamins, minerals, fatty acids, amino acids and more.

Introduction to Food Rating System Chart

In order to better help you identify foods that feature a high concentration of nutrients for the calories they contain, we created a Food Rating System. This system allows us to highlight the foods that are especially rich in particular nutrients. The following chart shows the nutrients for which this food is either an excellent, very good, or good source (below the chart you will find a table that explains these qualifications). If a nutrient is not listed in the chart, it does not necessarily mean that the food doesn't contain it. It simply means that the nutrient is not provided in a sufficient amount or concentration to meet our rating criteria. (To view this food's in-depth nutritional profile that includes values for dozens of nutrients - not just the ones rated as excellent, very good, or good - please use the link below the chart.) To read this chart accurately, you'll need to glance up in the top left corner where you will find the name of the food and the serving size we used to calculate the food's nutrient composition. This serving size will tell you how much of the food you need to eat to obtain the amount of nutrients found in the chart. Now, returning to the chart itself, you can look next to the nutrient name in order to find the nutrient amount it offers, the percent Daily Value (DV%) that this amount represents, the nutrient density that we calculated for this food and nutrient, and the rating we established in our rating system. For most of our nutrient ratings, we adopted the government standards for food labeling that are found in the U.S. Food and Drug Administration's "Reference Values for Nutrition Labeling." Read more background information and details of our rating system.

In-Depth Nutritional Profile for Collard greens

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