Collard refers to certain loose-leafed cultivars of Brassica oleracea, the same species as many common vegetables, including cabbage (Capitata Group)and broccoli (Botrytis Group). Collard is part of the Acephala Group of the species, which includes kale and spring greens. They are in the same cultivar group owing to their genetic similarity. The name “collard” comes from the word “colewort” (the wild cabbage plant).
The plants are grown for their large, dark-colored, edible leaves and as a garden ornamental, mainly in Brazil, Portugal, the Southern United States, many parts of Africa, the Balkans, Italy, Northern Spain, and Kashmir. Collard greens have been eaten for at least 2000 years, with evidence showing that the ancient Greeks cultivated several types of collard, as well as kale.
Collard greens are part of the cruciferous vegetable family. They contain nutrients that can play an important role in a healthful diet.
The cruciferous family includes bok choy, kale, broccoli, Brussels sprouts, cabbage, rutabaga, and turnips. Cruciferous vegetables are high in nutrients and low in calories.
HEALTH BENEFITS OF COLLARD GREENS
A diet that is rich in fruits and vegetables appears to help reduce the risk of many lifestyle-related health conditions.
A high intake of plant foods, such as collard greens, appears to decrease the risk of a number of health conditions, including obesity and overall mortality, diabetes, and heart disease.
■ BONE HEALTH
A low intake of vitamin K can increase the risk of osteoporosis and bone fracture.
Vitamin K acts as a modifier of bone matrix proteins, it improves calcium absorption, and it may reduce urinary excretion of calcium.
One cup of boiled collard greens provides 770 micrograms of vitamin K.
The 2015-2020 United States Dietary Guidelines recommend that a woman aged 19 to 30 years should consume 90 mcg a day of vitamin K, and a man of the same age should consume 120 mcg.
One cup of collard greens provides this much vitamin K several times over.
Studies suggest that people who eat plenty of cruciferous vegetables have a lower risk of developing various types of cancer, including cancer of the upper digestive tract, colorectal, breast cancer, and kidney cancer.
Cruciferous vegetables have sulfur-containing compounds known as glucosinolates.
These compounds may help prevent the cancer process at different stages of development for lung, colorectal, breast, and prostate cancers, and possibly melanoma, esophageal cancer, and pancreatic cancer.
In 2017, researchers published the results of a study involving nearly 3,000 people. They were looking for possible links between the incidence breast cancer and the consumption of cruciferous vegetables.
The findings suggested that consuming cruciferous vegetables may lower the risk of breast cancer, especially in women who have not yet reached menopausal. They note that cooking methods may make a difference, as cooking some cruciferous vegetables can reduce the levels of glucosinolates.
Whether this is true of collard greens or not was unclear from this study, as most people do not eat collard greens raw.
There is evidence that collard greens and other green vegetables that contain high amounts of chlorophyll can help to block the carcinogenic effects of heterocyclic amine. These substances are generated when grilling foods at a high temperature.
■ DIABETES AND LIVER FUNCTION
The 2015-2020 Dietary Guidelines for Americans recommend 22.4 to 28 grams of fiber a day for women, depending on age, and 28 to 33.6 grams a day for men.
Results of a study published in 2014 suggest that a high intake of fiber might reduce inflammation and glucose levels in people with type 1 diabetes. It may help people with type 2 diabetes to achieve better levels of blood sugar, lipids, and insulin.
One cup of boiled collard greens provides nearly 8 grams of fiber. Collard greens also contain an antioxidant known as alpha-lipoic acid.
Studies suggest that alpha-lipoic acid (ALA) can lower glucose levels, increase insulin sensitivity, and prevent changes related to oxidative stress in people with diabetes. It can also help to regenerate liver tissue.
Investigators have also observed that ALA may decrease the symptoms of peripheral neuropathy in people with diabetes.
However, it remains unclear whether ALA can be effective as a long-term treatment. In addition, studies have used intravenous ALA. Oral supplementation may not provide the same benefits.
Excessively high doses of ALA appear to produce adverse effects similar to those caused by too little. While “normal” amounts can help prevent oxidative stress, high levels may lead to cell damage.
Researchers have found that consuming collard greens improved liver function in rats with high blood pressure.
Collard greens are high in both fiber and water content. These help to prevent constipation, promote regularity, and maintain a healthy digestive tract.
■ HEALTHY SKIN AND HAIR
Collard greens have a high vitamin A content. Vitamin A is necessary for sebum production, and this keeps hair moisturized.
Vitamin A is crucial for the growth of all bodily tissues, including skin and hair. It also supports the immune system and the eyes and helps keep the body’s organ healthy.
Vitamin C enables the body to build and maintain levels of collagen, which provides structure to skin and hair.
An adult woman needs 75 mg of vitamin C a day, and a day, and a man needs 90 mg. A cup of boiled collard greens provides nearly 35 mg of vitamin C.
Iron prevent anemia, a common cause of hair loss. A lack of iron in the diet can affect how efficiently the body uses energy. Collard greens, spinach, lentils, tuna, and eggs are good source of iron.
Adults needs to consume 8 mg of iron a day, and women during their reproductive years need 18 mg. One cup of boiled collard greens provides 2.5 mg of iron.
■ SLEEP AND MOOD
Collard greens contain choline, an important neurotransmitter. Choline helps with mood, sleep, muscle movement, learning, and memory functions.
Choline also helps to maintain the structure of cellular membranes, the transmission of nerve impulses, the absorption of fat, and the reduction of chronic inflammation.
Folate, also present in choline, may help with depression, as it can prevent an excess of homocysteine from forming in the body.
Scientists have found high levels of homocysteine in people with bipolar disorder and depression related to alcohol use disorder.
Consuming folate may help reduce the risk of depressive symptoms in some people.
One cup of boiled collard greens, drained and without added salt, contains:
● 63 calories
● 5.15 (g) of protein
● 1.37 g of fat
● 10.73 g of Carbohydrate including 7.6 g of fiber and less than 1 g of sugar
● 268 milligrams (mg) of calcium
● 2.15 mg of iron
● 40 mg of magnesium
● 61 mg of phosphorus
● 222 mg of potassium
● 28 mg of sodium
● 0.44 mg of zinc
● 34.6 mg of vitamin C
● 30 mcg of folate
● 722 micrograms (mcg) of vitamin A (RAE)
● 1.67 mg of vitamin E
● 772.5 mcg of vitamin K
Collard greens are an excellent source of vitamin A, vitamin C, and calcium, a rich source of vitamin K, and a good source of iron, vitamin B-6, and magnesium.
They also contain thiamin, niacin, pantothenic acid, and choline.