Green leafy vegetables are healthy foods that can help complete a balanced diet. They are typically rich in nutrients and fiber and low in calories and fat.

The nutritional profiles of green leafy vegetables are generally associated with many health benefits. The United States Department of Agriculture (USDA) 2020–2025 Dietary Guidelines recommend that adults vary their vegetable intake and aim to fill half their plate with fruits and vegetables.

This article will discuss what green leafy vegetables are, how to identify them, their benefits, their side effects, and how to add them to the diet.

Green leafy vegetables, also called dark green leafy vegetables, leafy greens, or greens, are edible plant leaves. A person can eat some leafy greens raw, while others may require cooking. As the name implies, people can typically identify these vegetables by their green color and edible leaves.

Here are several examples of green leafy vegetables.

Kale

Kale is a vegetable belonging to the cabbage (Brassica) family. It has characteristic tough center stems and long leaves that curl at the ends. It is rich in nutrients, including fiber and antioxidants. A 2018 study suggests that consuming high amounts of dietary fiber may help prevent type 2 diabetes.

According to the USDA, 1 cup, or 118 grams (g), of cooked kale contains:

  • Calories: 43
  • Carbohydrates: 6.3 g
  • Sugars: 1.4 g
  • Fat: 1.4 g
  • Protein: 3.5 g
  • Fiber: 4.7 g

Collard greens

Like kale, collard greens, or simply collards, come from the cabbage family. They have large, fanlike leaves and tough stems. While people can eat them raw, they can be bitter and tough to chew, which is why many people may braise or steam them. Collards are rich in vitamin A, vitamin C, folate, vitamin K, and calcium.

According to the USDA, 1 cup (190 g) of cooked chopped collards contains:

  • Calories: 62
  • Carbohydrates: 10.7 g
  • Sugars: 0.8 g
  • Fat: 1.4 g
  • Protein: 5.2 g
  • Fiber: 7.6 g

Spinach

Spinach is another leafy green that contains many vitamins and nutrients, including iron, magnesium, phosphorus, folic acid, and calcium.

A 2016 review suggests that spinach may help delay the progression of Alzheimer’s disease. It also contains carotenoids, which may help prevent eye diseases and maintain eye health.

According to the USDA, 1 cup (30 g) of raw spinach contains:

  • Calories: 7
  • Carbohydrates: 1.1 g
  • Sugars: 0.1 g
  • Fat: 0.1 g
  • Protein: 0.9 g
  • Fiber: 0.7 g

Cabbage

Cabbage leaves vary from green to purple to white. People often saute, stir-fry, or boil cabbage. People also ferment cabbage to make kimchi and sauerkraut.

Cruciferous vegetables such as cabbages contain sulforaphane, a compound that may lower a person’s risk for cancer. A 2019 study suggests that this compound can reduce a person’s risk for breast cancer. It may also protect cells from oxidative damage during cancer radiation therapy and may lower the risk for stroke and high blood pressure.

According to the USDA, 1 cup (89 g) of chopped raw cabbage has:

  • Calories: 22
  • Carbohydrates: 5.2 g
  • Sugars: 2.9 g
  • Fat: 0.1 g
  • Protein: 1.1 g
  • Fiber: 2.2 g

Watercress

Watercress ranks at the top of the Centers for Disease Control and Prevention’s list of powerhouse fruits and vegetables. This slightly peppery and spicy aquatic plant also belongs to the cruciferous family.

Like other cruciferous plants, watercress may protect cells against chemotherapy-related damage and exercise-induced oxidative stress and help prevent liver toxicity.

According to the USDA, 1 cup (34 g) of raw watercress contains:

  • Calories: 4
  • Carbohydrates: 0.4 g
  • Sugars: 0.1 g
  • Fat: 0 g
  • Protein: 0.8 g
  • Fiber: 0.2 g

Romaine lettuce

Romaine lettuce, or cos lettuce, is a salad favorite for its crispy, mild-flavored leaves. It is high in antioxidants, which can help eliminate free radicals, boost immunity, and protect against cancer.

It also contains potassium, an important mineral for heart health, and beta carotene, which is essential for eye health. Beta carotene may help prevent macular degeneration, according to the National Institutes of Health.

According to the USDA, 1 cup (47 g) of shredded raw romaine lettuce contains:

  • Calories: 8
  • Carbohydrates: 1.6 g
  • Sugars: 0.6 g
  • Fat: 0.1 g
  • Protein: 0.6 g
  • Fiber: 1 g

Arugula

Arugula, or rocket, is a versatile salad green with tender leaves and a sharp, peppery flavor. People often eat it raw, while others may add it to soups and pasta. It offers the same benefits as other cruciferous vegetables.

According to the USDA, half a cup (10 g) of raw arugula contains:

  • Calories: 3
  • Carbohydrates: 0.4 g
  • Sugars: 0.2 g
  • Fat: 0.1 g
  • Protein: 0.3 g
  • Fiber: 0.2 g

Bok choy

Also called Chinese cabbage or pak choi, bok choy is another cruciferous vegetable packed with many vitamins and minerals. It also contains selenium, a mineral that can help protect against oxidative damage and infection.

According to the USDA, 1 cup (70 g) of shredded raw bok choy contains:

  • Calories: 9
  • Carbohydrates: 1.5 g
  • Sugars: 0.8 g
  • Fat: 0.1 g
  • Protein: 1.1 g
  • Fiber: 0.7 g

Beet greens

Beet leaves are edible and have an earthy taste. People can add them to salads and soups or saute or steam them for a side dish. They are rich in nutrients, including antioxidants.

According to the USDA, 1 cup (38 g) of raw beet greens contains:

  • Calories: 8.4
  • Carbohydrates: 1.6 g
  • Sugars: 0.2 g
  • Fat: 0.1 g
  • Protein: 0.8 g
  • Fiber: 1.4 g

Swiss chard

Swiss chard has dark leaves and thick stalks in various colors, which is why some people call it rainbow chard. Others may call it sea kale or leaf beet. The leaves have an earthy flavor, and the stalks taste sweet.

Aside from containing many nutrients, it also contains compounds called polyphenols. A 2021 study suggests that these compounds have the potential to stop cancer cell growth.

According to the USDA, 1 cup (36 g) of raw Swiss chard contains:

  • Calories: 6.8
  • Carbohydrates: 1.4 g
  • Sugars: 0.4 g
  • Fat: 0.1 g
  • Protein: 0.6 g
  • Fiber: 0.6 g

Leafy greens are healthy sources of carbohydrates. They also typically contain less fat and calories than many other foods but can contain protein and other nutrients. A 2020 study notes that green leafy vegetables often contain bioactive compounds such as niacin, omega-3-fatty acids, flavonoids, carotenoids, sulforaphane, and others.

These compounds can provide antioxidant and anti-inflammatory properties, which may lead to a vast array of health benefits, such as a reduced risk for health conditions like stroke, anemia, high blood pressure, certain cancers, and diabetes. They may also help improve gut health, immunity, and heart, bone, and skin health.

A 2018 study found that a daily serving of leafy greens may help slow cognitive decline that can come with aging.

Eating leafy greens is generally good for the health. However, some greens, such as collards, spinach, and chard, contain large amounts of vitamin K that may interact with blood thinners and lessen their effect. According to a 2016 review, people who take blood thinners should not try to avoid vitamin K. Instead, they should keep their vitamin K intake stable.

A 2017 study notes that some greens contain chemical substances known as “antinutrients,” such as oxalates, nitrates, and phytates. Feeding foods rich in nitrates to babies younger than 7 months can cause methemoglobinemia, or blue baby syndrome. However, this is unlikely. Blue baby syndrome is more likely to result from drinking contaminated water.

Foods high in oxalates can hinder calcium absorption and may cause kidney stone formation. However, a 2012 study states that people can avoid these risks by drinking fluids and taking enough calcium.

Cruciferous vegetables typically contain glucosinolates, which can interfere with iodine absorption. People with iodine deficiency, such as those who have hypothyroidism or goiter, are more susceptible.

The same 2017 study states that blanching, boiling, or cooking these vegetables can reduce the level of these antinutrients.

Some ways people can try to add leafy greens to their diet include:

  • Salads. Put greens that people can eat raw, such as spinach and beet greens, into a bowl; add some vinaigrette or lemon juice; and eat them as a salad.
  • Healthy bowls. Make a healthy bowl by adding greens to a bowl full of proteins, fruits, and whole grains.
  • Wraps. Combine romaine, cabbage, or Swiss chard leaves with other ingredients as a filling for a wrap.
  • Soups. Some greens, such as bok choy and Swiss chard, are soup staples. Stir chopped greens into soups or stews during the last few minutes of cooking.
  • Pizza. Replace meats and processed toppings with greens to make a healthier pizza.
  • Sautes and stir-fries. Toss greens together with noodles, vegetables, nuts, and seafood.
  • Pesto. Use leafy greens in place of basil as the staple green in pesto.
  • Juice. Add some greens, such as kale and parsley, when making juice for extra nutrients and a pungent kick without the fullness that smoothies can cause.
  • Sandwich. Aside from the usual tomatoes, pickles, and avocados, people can add greens like lettuce, arugula, and spinach to sandwiches.
  • Sauces. People can chop or puree leafy greens and add them to sauces. For example, people can blend vegetables such as beet greens and add them to marinara sauce.
  • Smoothies. Combine greens like spinach with other healthy fruits and vegetables such as beets, carrots, cucumber, and ginger to make a healthy green drink.
  • Add-ons. Greens can add extra flavor to meals. People can cook them in many ways, such as by grilling, steaming, boiling, braising, and stewing.

Green leafy vegetables are nutrient-packed foods that may offer a variety of health benefits. Regularly consuming servings of greens can be beneficial for health and may help prevent some health conditions.

Although greens are nutritious, they can interact with certain drugs, and overconsumption can have side effects. Some greens contain antinutrients that limit nutrient absorption. However, a person can typically remedy this by adequately cooking the vegetables.

https://www.medicalnewstoday.com/articles/green-leafy-vegetables