Black beans, also known as turtle beans because of their hard shell-like appearance, are classified as legumes. The beans are actually the edible seeds of the legume plant.
Like other legumes such as peanuts, peas and lentils, black beans are prized for their high protein and fiber content. They also contain several other key vitamins and minerals that are known to benefit human health.
This MNT Knowledge Center feature is part of a collection of articles on the health benefits of popular foods. It provides a nutritional breakdown of the black bean and an in-depth look at its possible health benefits, how to incorporate black beans into your diet and any potential health risks of consuming black beans.
Contents of this article:
Nutritional breakdown of black beans
Black beans are prized for their high protein and fiber content.
One-half cup (92g) of raw black beans contains approximately 312 calories6.
That same half cup serving provides approximately 44% of daily iron needs, 55% of thiamin, 100% of folate, 37% of magnesium, 40% of phosphorus, 39% of potassium and 13% of zinc needs7.
Black beans also offer a variety of phytonutrients like saponins, anthocyanins, kaempferol, and quercetin, all of which possess antioxidant properties.
Possible health benefits of consuming black beans
Maintaining healthy bones
The iron, phosphorous, calcium, magnesium, manganese, copper and zinc in black beans all contribute to building and maintaining bone structure and strength.4
Calcium and phosphorus are important in bone structure, while iron and zinc play crucial roles in maintaining the strength and elasticity of bones and joints. 99% of the body’s calcium supply and 80% of its phosphorus stores are contained in bone, which makes it extremely important to get sufficient amounts of these nutrients from the diet.
Lowering blood pressure
Maintaining a low sodium intake is essential to lowering blood pressure. Black beans are naturally low in sodium and contain potassium, calcium, and magnesium, all of which have been found to decrease blood pressure naturally. Be sure to drain and rinse canned black beans to reduce sodium content.5
Studies have shown that type 1 diabetics who consume high-fiber diets have lower blood glucose levels and type 2 diabetics may have improved blood sugar, lipids and insulin levels. One cup (172g) of cooked black beans contributes 15 grams of fiber8.
The Dietary Guidelines for Americans recommends 21-25 grams of fiber per day for women and 30-38 grams per day for men.
Warding off heart disease
The black bean’s fiber, potassium, folate, vitamin B6 and phytonutrient content, coupled with its lack of cholesterol, all support heart health. The fiber in black beans helps lower the total amount of cholesterol in the blood and decrease the risk of heart disease.
Vitamin B6 and folate prevent the buildup of a compound known as homocysteine. When excessive amounts of homocysteine accumulate in the body, it can damage blood vessels and lead to heart problems.
The quercetin and saponins found in black beans also aid in cardioprotection. Quercetin is a natural anti inflammatory that appears to reduce the risk of atherosclerosis and protect against the damage caused by low-density lipoprotein (LDL) cholesterol.3 Research also indicates that saponins help lower blood lipid and blood cholesterol levels, which prevents damage to the heart and blood vessels.
- Selenium is a mineral that is not present in most fruits and vegetables but can be found in black beans. It plays a role in liver enzyme function, and helps detoxify some cancer-causing compounds in the body. Additionally, selenium prevents inflammation and also decreases tumor growth rates2
- Saponins prevent cancer cells from multiplying and spreading throughout the body
- Fiber intakes from fruits and vegetables like black beans are associated with a lowered risk of colorectal cancer
- Black beans are high in folate, which plays a role in DNA synthesis and repair, thus preventing the formation of cancer cells from mutations in the DNA.1
Because of their fiber content, black beans help to prevent constipation and promote regularity for a healthy digestive tract.
Weight loss and satiety
Dietary fiber is commonly recognized as an important factor in weight loss and weight management by functioning as a “bulking agent” in the digestive system. High fiber foods increase satiety and reduce appetite, making you feel fuller for longer and thereby lowering your overall calorie intake.
Consuming fruits and vegetables of all kinds has long been associated with a reduced risk of many lifestyle-related health conditions. Many studies have suggested that increasing consumption of plant foods like black beans decreases the risk of obesity, diabetes, heart disease and overall mortality while promoting a healthy complexion and hair, increased energy and overall lower weight.
How to incorporate more black beans into your diet
Black beans are available year-round and are often found in grocery stores either dried and packaged or canned. They have a dense, almost meaty texture that makes them a popular source of protein in vegetarian dishes.
If you are using canned black beans, be sure to select those with no added sodium and to drain and rinse all canned beans to decrease sodium content.
When preparing dried black beans, it is important to sort (pick out any small rocks or other debris that may have wound up in the package), wash and soak them in water for about 8 to 10 hours before cooking in order to achieve optimum flavor and texture.
You can tell they are finished soaking when you can split them easily between your fingers. Be careful not to soak them for more than 12 hours, otherwise they become mushy and bland-tasting. Soaking dried legumes reduces the amount of time needed to cook them, and also helps remove some of the oligosaccharides that cause gastrointestinal distress.
Mix black beans with vegetables, cheese and salsa to create a delicious taco salad.
- Make a hearty black bean soup to warm you up on cold days by blending cooked black beans with onions, tomatoes, and your favorite spices
- Add black beans to your list of burrito fillings
- Blend cooked black beans with garlic, onion, fresh cilantro and lime juice for a quick and easy bean dip
- Mix black beans, onions, lettuce, tomatoes, avocado, sharp cheddar cheese and salsa together for a simple taco salad.
Try these healthy recipes using black beans:
Potential health risks of consuming black beans
Legumes contain oligosaccharides known as galactans – complex sugars that the body cannot digest because it lacks the enzyme alpha-galactosidase, which is needed to break them down. Because of this, the consumption of legumes such as black beans has been known to cause some people intestinal gas and discomfort.
If you experience these symptoms associated with legume intake, you may consider slowly introducing them into your diet or taking any dietary supplements containing alpha-galactosidase. Another option is to drain the water used to soak dried legumes. This removes two oligosaccharides, raffinose, and stachyose, and eliminates some of the digestive issues.
It is the total diet or overall eating pattern that is most important in disease prevention and achieving good health. It is better to eat a diet with a variety than to concentrate on individual foods as the key to good health.
Written byMegan Ware, RDN, LD, registered dietitian and nutritionist and Helen Yuan, nutrition intern.