What Are Collard Greens? Nutrition Facts and Benefits

collard greens
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What Are Collard Greens?

What are collard greens? Collard greens, or collards, are loose-leafed plants that belong to the Brassica oleracea species and cruciferous family.

There are many reported health benefits of collard greens, which may extend to your digestive system, heart health, bone health, and skin and hair health. Studies indicate the vegetable can also reduce your glaucoma risk, prevent cancer, and provide detox support.

Collard greens are part of the Acephala group, which also includes kale, Brussels sprouts, cauliflower, broccoli, cabbage, and Swiss chard. The plant has large, dark-colored, and edible leaves, and like kale, it has an upright stalk that grows up to two feet tall.

Collard greens grow in Portugal, Brazil, the southern United States, and many parts of Africa, northern Spain, northern India, Kashmir, southern Croatia, and Bosnia and Herzegovina.

In this article, we will further explain the benefits of collard greens. You will also learn more about collard greens nutrition facts, how to use them, and possible risks and precautions associated with this leafy plant.

Plus, we will show you how to grow collard greens in your garden. Let’s get started…

Nutrition Facts of Collard Greens

Collard greens’ nutrients are what give this vegetable many of its health benefits. These greens are extremely high in vitamin K, vitamin A, vitamin C, folate, manganese, and calcium. They’re also a good vegetable source of fiber and protein.

Other key nutrients in collard greens include vitamin B1, vitamin B2, vitamin B3, vitamin B5, vitamin B6, vitamin E, choline, betaine, iron, magnesium, phosphorus, potassium, zinc, copper, and selenium.

The following is a comprehensive collard greens nutrition information chart for one cup, or 190 g, of cooked, boiled, and drained collard greens.

Nutrient Amount Daily Value
Calories 49.4 2.00%
Carbohydrates 9.3 g 3.00%
Fiber 5.3 g 21.00%
Protein 4.0 g 8.00%
Total Fat 0.7 g 1.00%
Iron 2.2 mg 12.00%
Manganese 0.8 mg 41.00%
Copper 0.1 mg 4.00%
Calcium 266 mg 27.00%
Magnesium 38.0 mg 27.00%
Phosphorus 57.0 mg 6.00%
Potassium 220 mg 6.00%
Selenium 0.9 mcg 1.00%
Zinc 0.4 mg 3.00%
Folate 177 mcg 44.00%
Vitamin B1 0.1 mg 5.00%
Vitamin B2 0.2 mg 12.00%
Vitamin B3 1.1 mg 5.00%
Vitamin B5 0.4 mg 4.00%
Vitamin B6 0.2 mg 12.00%
Vitamin A 15416 IU 308.00%
Vitamin C 34.6 mg 58.00%
Vitamin E 1.7 mg 8.00%
Vitamin K 836 mcg 1,045.00%
Choline 60.4 mg N/A
Betaine 0.2 mg N/A

N/A—Not Applicable

What Are the Benefits of Collard Greens?

Like all cruciferous vegetables, collard greens are high in sulfur-containing compounds like indole-3-carbinol that reduce cancer risk, and glucosinolates that support detoxification.

Other anti-cancer properties include sulforaphane and diindolylmethane. Collard greens and other cruciferous vegetables also contain glutathione, which helps cleanse and detoxify the body, fight cancer, boost the immune system, and protect the body against environmental toxins.

In this section, we will further explain the benefits of collard greens, including how they may prevent cancer; reduce glaucoma risk; and support detoxification and bone, heart, skin, hair, and digestive health.

1. May Prevent Cancer

Collard greens have anti-inflammatory, antioxidant, and detoxification properties that could help prevent and treat cancer. The sulfur-containing compounds like glucosinolates are responsible for their cancer prevention and treatment potential.

These chemicals break down during the chewing and digestion process into compounds called thiocyanates, isothiocyanates, and indoles that prevent cancer growth. Research suggests that these compounds protect mice and rats against various cancer forms, such as colon, bladder, breast, lung, stomach, prostate, colorectal, pancreatic, esophageal, melanoma, and liver cancers.

One 2002 review published in the journal Nutrition and Cancer found that Brassica vegetables like collard greens were significantly associated with a reduced risk of prostate cancer.

Collard greens also contain a high amount of chlorophyll, and this pigment can help block the carcinogenic effects of heterocyclic amines—which are released when grilling foods at high temperatures.

2. Provide Detox Support

Like other cruciferous vegetables, collard greens are considered a natural detoxifier. They may help eliminate toxins from the body.

Collard greens contain isothiocyanates, which are made from glucosinolates. Glucosinolates help activate and regulate detoxification enzymes, and also trigger the liver to produce detoxifying enzymes that block free radicals that attack your DNA.

Regular collard greens consumption can help your body eliminate toxins that come from pharmaceutical drugs, pesticides, pollutants, and processed foods. The glutathione in collard greens are also able to help cleanse and detoxify the body.

3. Support Bone Health

A deficiency, or low intake, of vitamin K can increase your risk of bone fractures, osteoporosis, weakened bones, and tooth decay.
A cup of cooked collard greens is incredibly high in vitamin K. In fact, collard greens contain 836 mcg, or 1,045% of the recommended daily value of vitamin K.

Vitamin K acts like a modifier of bone matrix proteins and improves calcium absorption. Research also suggests that vitamin K not only increases bone mineral density in those with osteoporosis, but it also decreases fracture rates.

4. Benefit Healthy Skin and Hair

Collard greens contain antioxidants that help keep your skin and hair healthy. For example, vitamin A is essential for skin health, such as fighting against acne.

Vitamin A is also necessary for sebum production, and this helps keep your hair moisturized. A vitamin A deficiency can lead to a poor skin complexion.

The vitamin C in collard greens helps the body build and maintain collagen, and this provides structure to both your hair and skin. The iron in collard greens can also prevent anemia—a common cause of hair loss.

5. Support the Digestive System

The fiber and water in collard greens are great for the digestive tract, and can treat irritable bowel syndrome (IBS) and promote regular bowel movements. IBS can cause symptoms such as constipation, diarrhea, gas, and abdominal pain.

Since a low-fiber diet is a common cause of IBS, high-fiber foods like collard greens can help treat IBS. The glucoraphanin in collard greens can also protect the stomach lining by preventing bacterial overgrowth and the attachment of bacteria to the stomach wall.

6. Support Heart Health

Since collard greens can lower inflammation, the vegetable in turn has a positive effect on cardiovascular health. The vitamin K in collard greens, for instance, is critical for protecting cells that line your blood vessels, or your arteries and veins.

Vitamin K has been found to prevent the calcification of arteries, which can lead to heart attacks. Vitamin K carries calcium from the arteries; therefore, it will not harden into plaque deposits. As a result, collard greens consumption can help lower blood pressure and reduce your risk of heart attack and stroke.

The high amounts of fiber in collard greens can help lower cholesterol. The fiber will bind to cholesterol in the digestive system, and this causes cholesterol to be excreted from the body.

Studies have shown that fiber significantly sustains reductions in LDL (low-density lipoprotein), or the “bad” cholesterol, without increasing triglycerides or lowering the HDL (high-density lipoprotein), or good cholesterol.

7. Reduce Glaucoma Risk

Glaucoma is an eye disease that can lead to optic nerve damage. A study published in the American Journal of Ophthalmology in 2013 found that vegetables high in vitamin A and vitamin C may be linked with a reduced risk of glaucoma in 584 older African-American women.

For the study, consumption of more than one serving of collard greens and kale reduced the likelihood of developing glaucoma by 57%.

Tips for Using Collard Greens

When buying collard greens, look for firm, deep-green leaves. Smaller leaves are also tenderer with a milder flavor. Store collard greens in the refrigerator. When you steam collard greens for about 10 minutes, this helps retain nutrient content.

Collard greens can be used in salads, wraps, sandwiches, casseroles, soups, and smoothies, and can be boiled, braised, or sautéed. It is also a good idea to sauté fresh onions and garlic in extra-virgin olive oil, and then add collard greens until they become tender.

There are also benefits of collard greens juice, so you can combine collard greens with other vegetables and fruits like apples, celery, and cucumber for juicing.

Avoid frying collard greens in lard or bacon fat or overcooking collard greens, since this can lead to a bitter and strong sulfur taste.

Risks and Precautions While Using Collard Greens

Although there are many benefits of collard greens, there are some potential risks and precautions to consider. For example, it’s best to choose organic collard greens as conventionally grown greens may be contaminated with organophosphate insecticides, which are highly toxic.

Collard greens also contain substances called oxalates that are not a problem when are eaten in normal, moderate amounts. However, high levels of oxalates may interfere with mineral absorption and cause a problem for those with gallbladder issues.

That being said, most experts agree that oxalates are not an issue for most people and the benefits of collard greens outweigh the negative effects of oxalates.

Also, people taking blood thinners like warfarin should not suddenly increase or reduce their intake of foods high in vitamin K, such as collard greens. This is because vitamin K plays a key role in blood clotting.

Bloating is also a common side effect of high-fiber foods such as collard greens.

Can You Grow Collard Greens in Your Garden?

How do you grow collard greens in your garden?

The best collard greens grow in an environment with moist and fertile soil. You should plant your seeds in rows at least three feet apart since collard greens need room to grow. Also, choose an area with a lot of natural sun.

Although it takes 60 to 75 days for collard greens to reach full maturity, the leaves can be picked whenever they are an edible size, from the bottom of the inedible stalks.

Collard greens are often planted in late summer to early autumn for a winter harvest in southern areas. In northern areas, collard greens should be planted in mid-summer for a fall or winter harvest or in the early spring for a summer harvest. Collard greens can tolerate frost, and this can improve the flavor of collard greens.

When growing collard greens, it is important to be aware of pests called aphids, which feed on collard greens and cabbage and may leave holes in the leaves. When aphids are spotted, keep an eye on the underside of the collard green leaves on a daily basis.

Final Thoughts on Collard Greens

Collard greens belong to the Brassica oleracea species and cruciferous family. In this article, we explored the many benefits of collard greens. For instance, collard greens contain particularly high amounts of vitamin K, vitamin C, vitamin A, folate, manganese, and calcium.

As a result of these nutrients, the health benefits of collard greens may include preventing cancer, reducing the risk of glaucoma, and providing detoxification support. Collard greens may also benefit your bones, heart, skin, hair, and digestive system.

Collard greens can be used in salads, sandwiches, wraps, smoothies, juices, soups, and casseroles. They can also be steamed, boiled, sautéed, and braised. Still, you should avoid overcooking collard greens because this can lead to a strong and bitter sulfur taste.

Also read:

“Collard Greens: Fight Cancer, Provide Detox Support & More,” Dr. Axe; https://draxe.com/collard-greens/, last accessed August 27, 2018.
“Collards, cooked, boiled, drained, without salt Nutrition Facts,” SELFNutritionData; https://nutritiondata.self.com/facts/vegetables-and-vegetable-products/2411/2, last accessed August 27, 2018.
Ware, M., “Why you should eat your collard greens,” Medical News Today, Aug. 16, 2018; https://www.medicalnewstoday.com/articles/277957.php, last accessed August 27, 2018.
Kristal, A., et al., “Brassica vegetables and prostate cancer risk: a review of the epidemiological evidence,” Nutrition and Cancer, 2002; 42(1): 1-9, doi: 10.1207/S15327914NC421_1.
de Vogel, J., et al., “Green vegetables, red meat and colon cancer: chlorophyll prevents the cytotoxic and hyperproliferative effects of haem in rat colon,” Carxinogenesis Integrative Cancer Research, Feb. 2005; 26(2): 387-393, doi: 10.1093/carcin/bgh331.
Weber, P., “Vitamin K and bone health,” Nutrition, Oct. 2001; 17(10): 880-887, PMID: 11684396.
Kahlon, T., et al., “Steam cooking significantly improves in vitro bile acid binding of collard greens, kale, mustard greens, broccoli, green bell pepper, and cabbage,” Nutrition Research, June 2008; 28(6): 351-357, doi: 10.1016/j.nutres.2008.03.007.
Giaconi, J., et al., “The Association of Consumption of Fruits/Vegetables with Decreased Risk of Glaucoma among Older African American Women in the Study of Osteoporotic Fractures,” American Journal of Ophthalmology, Oct. 2012; 154(4): 635-644, doi: 10.1016/j.ajo.2012.03.048.
Allen, J., “Can Collard Greens Cause Bloating?” Livestrong, October 3, 2017; https://www.livestrong.com/article/518838-can-collard-greens-cause-bloating/, last accessed August 27, 2018.
Badgett, B., “Tips on How to Grow Collard Greens,” Gardening Know How; https://www.gardeningknowhow.com/edible/vegetables/greens/growing-collard-greens.htm, last accessed August 27, 2018.