Black Beans: Health Benefits, Facts, Research
Black beans are classified as legumes. Also known as turtle beans because of their hard, shell-like appearance, black beans are, in fact, the edible seeds of the 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 profile 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.
Fast facts on black beans
Here are some key points about black beans. More detail and supporting information is in the main article.
- Among other benefits, black beans may help strengthen bones
- Black beans contain quercetin and saponins which can protect the heart
- Black beans contain around 114 kilocalories per half-cup
Possible health benefits of consuming black beans
Let's examine the potential health benefits of black beans:
1) Maintaining healthy bones
Black beans are high in protein and fiber.
The iron, phosphorous, calcium, magnesium, manganese, copper, and zinc in black beans all contribute to building and maintaining bone structure and strength.
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.
Roughly 99 percent of the body's calcium supply, 60 percent of its magnesium, and 80 percent of its phosphorus stores are contained in bone; this means it is extremely important to get sufficient amounts of these nutrients from the diet.
2) Lowering blood pressure
Maintaining a low sodium intake is essential for keeping blood pressure at a normal level. 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 purchase low sodium canned options and still drain and rinse to further reduce sodium content.
3) Managing diabetes
Studies have shown that individuals with type 1 diabetes who consume high-fiber diets have lower blood glucose levels; additionally, type 2 diabetics may have improved blood sugar, lipids, and insulin levels. One cup (172 grams) of cooked black beans contributes 15 grams of fiber.
The Dietary Guidelines for Americans recommends 21-25 grams of fiber per day for women and 30-38 grams per day for men.
4) 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.
Research also indicates that saponins help lower blood lipid and blood cholesterol levels, which prevents damage to the heart and blood vessels.
5) Preventing cancer
- 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 decreases tumor growth rates.
- 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.
6) Healthy digestion
Because of their fiber content, black beans help to prevent constipation and promote regularity for a healthy digestive tract. They also provide fuel for the healthy bacteria in the colon.
7) Weight loss
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 (a sense of fullness) and reduce appetite, making an individual feel fuller for longer, thereby lowering overall calorie intake.
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.
Nutritional profile of black beans
According to the National Nutrient Database one-half cup (86g) of cooked black beans contains approximately:
- Energy - 114 kilocalories
- Protein - 7.62 grams
- Fat - 0.46 grams
- Carbohydrate - 20.39 grams
- Fiber - 7.5 grams
- Sugars - 0.28 grams
- Calcium - 23 milligrams
- Iron - 1.81 milligrams
- Magnesium - 60 milligrams
- Phosphorus - 120 milligrams
- Potassium - 305 milligrams
- Sodium - 1 milligram
- Zinc - 0.96 milligrams
- Thiamin - 0.21 milligrams
- Niacin - 0.434 milligrams
- Folate - 128 micrograms
- Vitamin K - 2.8 micrograms
Black beans also offer a variety of phytonutrients like saponins, anthocyanins, kaempferol, and quercetin, all of which possess antioxidant properties.
As with many beans and legumes, black beans contain starch - a form of complex carbohydrate. Starch acts as a "slow burn" energy store that is slowly digested by the body, preventing a spike in blood sugar levels.
Incorporating 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 them. 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 at least 8-10 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. Soaking dried legumes reduces the amount of time needed to cook them, and also helps remove some of the oligosaccharides that cause gastrointestinal distress. Soaking beans for longer periods can help to reduce phytates, which may reduce mineral absorption.
Mix black beans with vegetables, cheese, and salsa to create a delicious taco salad.
- Make a hearty black bean soup by blending cooked black beans with onions, tomatoes, and your favorite spices
- Add black beans to burritos
- 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 necessary enzyme - alpha-galactosidase.
Because of this, the consumption of legumes, including black beans, is 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. Another option is to soak beans longer, opt for sprouted beans, and/or 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 overall eating pattern that is most important in preventing disease and attaining good health. It is better to eat a diet with a variety than to concentrate on individual foods as the key to good health.
Lentils are a rich source of dietary fiber.
Lentils are a powerhouse of nutrition. They are a good source of potassium, calcium, zinc, niacin and vitamin K, but are particularly rich in dietary fiber, lean protein, folate and iron. The Centers for Disease Control and Prevention reports that eating plenty of nutrient-dense foods like lentils can lessen your risk of many serious medical problems. Lentils are not only one of the oldest commonly consumed legumes in history, but they are also one of the simplest to prepare since they don’t require a lengthy soaking time like other beans. Some people may experience flatulence and abdominal discomfort when initially adding legumes like lentils into their diet. Cookbook author Mark Bittman recommends incorporating lentils into regular meals slowly, over a period of weeks, and using a commercial digestive aid.
A single cup of cooked lentils contains 16 grams of dietary fiber, or 63 percent of the U.S. Department of Agriculture’s recommended daily allowance of fiber for an adult man or woman on a 2,000-calorie diet. Lentils contain some soluble fiber, but are an outstanding source of insoluble fiber. According to The Cancer Project, a diet that includes plenty of insoluble fiber can regulate bowel movements, promote digestive system health and may significantly decrease the risk of colon, breast, throat and esophageal cancer. Fiber-rich foods like lentils may also help prevent stroke, heart disease, diabetes, high blood cholesterol and hypertension.
Cooked lentils provide 18 grams of protein per cup, with less than 1 gram of fat, negligible saturated fat and no cholesterol. When compared to beef, poultry and fish, all of which are good sources of protein but contain much higher amounts of saturated fat and cholesterol, the Harvard School of Public Health names legumes such as lentils a better protein choice. A 2012 study published in the “Archives of Internal Medicine” reported that substituting lean protein sources like beans for red meat could lower your overall risk of dying from most diseases, including cancer and heart disease. Lentils do not contain all of the amino acids required by the body for protein synthesis. Combine them with a grain like rice or whole-wheat bread for a meal providing complete protein.
Each cup of cooked lentils has 358 micrograms of folate. This amount supplies nearly 100 percent of the 400-microgram daily requirement of folate for adults. Folate, also known as folic acid or vitamin B-9, supports nervous system health, aids in energy metabolism and is required for the synthesis of DNA, RNA and red blood cells. If your diet lacks adequate folate, you may be more likely to develop cancer, depression, heart disease and age-related vision or hearing loss. It is especially important for pregnant women to include folate-rich foods like lentils in their diets. Pregnant women who eat at least 600 micrograms of folate daily may lessen the risk of their child being born with a birth defect.
A cup of lentils provides 87 percent of the iron men need daily and 38 percent of the amount a woman needs. The body uses iron to produce red blood cells and adenosine triphosphate, or ATP. People who are deficient in iron may develop anemia or neurological problems like attention-deficit hyperactivity disorder. The iron in plant-based foods like lentils is nonheme iron, a form of iron that is not absorbed as easily as the heme iron in meat, poultry and fish. You can increase the amount of iron you get from lentils by eating the legumes with meat or with a rich source of vitamin C. Serve lentils in meat-based soups or braises, or toss them into salads featuring dark, leafy greens and orange or grapefruit segments.