Black beans, kidney beans, pinto beans and navy beans are all one species, Phaseolus vulgaris, the common bean. What sets black beans apart is the coat. Lab analysis of black bean varieties found the pigment in the outer layer of the seed coat, mostly delphinidin with smaller amounts of petunidin and malvidin, all anthocyanins. In lab tests, boiling and steaming sharply reduced these pigments, and steaming kept more total phenolics than boiling.
A cup of boiled black beans (172 g) has 227 calories, 15 g of fiber and 15.2 g of protein, plus 64% of the daily value for folate and 40% for copper. Protein supplies about 30% of the calories. These numbers are for beans cooked without salt. Cooked beans are about two thirds water (65.7 g per 100 g), so dry beans hold far more per gram and the two should not be compared directly.
Black beans are often eaten with rice, and two small crossover trials tested that pairing: rice with black beans gave a smaller blood sugar rise than rice alone, in adults with type 2 diabetes and in healthy women. Bean industry groups helped fund some black bean research, including the first of those trials, so the funding is stated on each card. One 8-person trial found that the darker beans, black and red kidney, relaxed blood vessels more than paler ones, which is a hint and not proof that the coat matters.
Health benefits of black beans
The top findings from 25 studies, strongest evidence first
What the stars mean
- Strong. Several randomized trials, pooled in a meta-analysis, point the same way, or regulators (FDA or EFSA) have approved the claim.
- Moderate. Good randomized trials support it, but there are fewer of them, or their results vary.
- Limited. Small, short or single trials, or mixed results. Promising, but it needs confirmation.
Population and lab studies get no stars: they show a link or a mechanism, not proof.
How we rate evidence →- ★★★Lower “bad” LDL cholesterolAbout 130 g a day of pulses (beans, lentils, chickpeas, peas) lowered LDL by 0.14 mmol/L across 38 trials. In a trial of canned beans that included black beans, a cup a day lowered it by about 8%.
- ★★Lower fasting blood sugar, but results variedAcross 41 trials, pulses (chickpeas, beans, peas, lentils) lowered fasting blood glucose and longer-term blood sugar markers. Differences between trials were large.
- ★★Slightly lower blood pressureSwapping pulses in for other foods lowered the top number by about 2 points (2.25 mm Hg systolic) in 8 controlled feeding trials.
- ★★Slightly more weight lossDiets with about one serving a day of pulses led to 0.34 kg more weight loss over a median of 6 weeks. The effect was small.
- ★Smaller blood sugar rise after black bean mealsAdding black beans to rice lowered blood sugar after the meal, compared with rice alone. This held in 17 adults with type 2 diabetes and in 12 healthy women.
All 25 studies, strongest evidence first
Eating about 130 g a day of whole pulses lowered LDL cholesterol by 0.14 mmol/L in trials of beans, lentils, chickpeas and peas
Pooled pulses, not black beans alone. Meta-analysis of 38 randomized trials (2,095 people) lasting a median of 6 weeks. Non-HDL cholesterol fell 0.22 mmol/L and HDL cholesterol dipped by 0.03 mmol/L, with similar results for each pulse type. For beans, LDL kept falling as intake rose up to 1 cup a day (0.25 mmol/L per half cup). The authors rate the certainty of the evidence moderate to high for most results.
About 120 g a day of a bean mix that included black beans for 6 weeks lowered LDL cholesterol by 0.21 mmol/L compared with rice, while a pea mix did not
Randomized single-blind trial in adults with mildly raised cholesterol, 60 per group, in two Canadian cities. The beans were black, great northern, navy and pinto, so black beans were one part of the mix. Total cholesterol fell 0.28 mmol/L, while triglycerides, glucose and blood pressure did not change. Alberta Innovates Bio Solutions and Alberta Pulse Growers supported the trial and, the paper says, had no role in its design, analysis or publication.
Eating 1 cup (180 g) of canned beans a day for 4 weeks lowered LDL cholesterol by about 8%, while half a cup did not differ from rice
Multicenter randomized crossover trial in 73 adults with raised LDL cholesterol. The beans rotated daily between black, navy, pinto, dark red kidney and white kidney, so black beans were one of five. LDL on the full cup fell 8.08% from the start of the period and rose 0.49% on white rice. Total cholesterol fell about 5% on the cup, and other lipids and blood sugar markers did not differ.
Across 41 trials, pulses lowered fasting blood glucose and longer-term blood sugar markers, but results varied widely
Pooled pulses (chickpeas, beans, peas, lentils), not black beans alone. Meta-analysis of randomized trials lasting at least 7 days, in people with and without diabetes. Pulses alone lowered fasting glucose by a standardized 0.82, and pulses in low glycemic index diets lowered HbA1c or fructosamine by 0.28. Differences between trials were large and mostly unexplained, and the authors call for larger, better trials.
Pulses swapped in for other foods lowered systolic blood pressure by 2.25 mm Hg
Pooled pulses, not black beans alone. Meta-analysis of 8 controlled feeding trials (554 people, with and without high blood pressure) lasting at least 3 weeks. Mean arterial pressure fell 0.75 mm Hg, and the drop in diastolic pressure was not significant. Results differed a lot between trials, and the authors ask for larger, better trials.
Diets with about one serving a day of pulses led to 0.34 kg more weight loss over a median of 6 weeks
Pooled pulses (beans, lentils, chickpeas and dry peas), not black beans alone. Meta-analysis of 21 randomized trials (940 people) at a median intake of 132 g a day, with little difference between studies. The effect was small and also appeared in diets not meant to cut calories. Six trials hinted at lower body fat percentage, and long-term effects are unknown.
Black beans with rice lowered the blood sugar rise after a meal compared with rice alone in adults with type 2 diabetes
Randomized crossover trial in 17 adults with type 2 diabetes who ate white rice alone, or with pinto, black or dark red kidney beans, each meal matched for 50 g of available carbohydrate. Blood sugar was lower than after rice alone at 90, 120 and 150 minutes for all three bean meals, and the total rise was smaller for black and pinto beans but not kidney beans. The US Dry Bean Council funded the study in part, and a canned bean company donated the beans.
Black beans with rice lowered blood sugar at 60, 90 and 120 minutes after a meal compared with rice alone in healthy women
Randomized crossover trial in 12 healthy women aged 18 to 65 who ate white rice, black beans with rice or chickpeas with rice, each matched for 50 g of available carbohydrate, at least 7 days apart. The chickpea meal also differed from rice at 60 and 90 minutes. Insulin was measured too, but the abstract reports only the glucose results.
A meal with black beans lowered after-meal insulin in adults with metabolic syndrome compared with meals matched for fiber or antioxidant capacity
Pilot randomized crossover trial in 12 adults with metabolic syndrome who ate a Western-style meal with black beans, or a meal matched for fiber or for antioxidant capacity, with blood drawn for 5 hours. Oxidized LDL did not differ by meal. The USDA, UC Davis and the US Dry Bean Council funded it, and the paper says the sponsors had no role in the study.
A breakfast tortilla with 135 g of black beans kept older adults about as full as one with 80 g of beef
Randomized crossover trial in 35 adults averaging 72 years old, who also ate a tortilla with red kidney beans. Fullness and satisfaction rose and hunger fell after all three meals, and intake at a pizza lunch and 24-hour energy intake did not differ. The Ontario Bean Growers supported the work.
Whole black beans in a meal raised the gut hormones CCK and PYY more than added fiber did in adults with metabolic syndrome
Pilot randomized crossover trial in 12 adults with metabolic syndrome who ate meals matched for energy and macronutrients with no added fiber, added fiber or whole black beans. All three meals gave a similar feeling of fullness over 5 hours, and the added-fiber meal did better on prospective food consumption. Insulin after the bean meal was lower than after the no-fiber meal.
Fewer than half of adults reported more gas in the first week of eating pinto or baked beans, and 3 to 11% did so even on control foods
Questionnaires from 3 feeding studies in which adults ate a half cup of pinto beans, black-eyed peas or baked beans a day for 8 or 12 weeks (17 and 29 people in two crossover trials, 40 per group in the third). Only 19% reported more gas with black-eyed peas. These were not black beans, and the authors note individual variation.
Eating ¾ cup of black beans, unlike white rice, did not raise systolic blood pressure 2 hours later in people with stiff arteries
Pilot randomized crossover trial in 9 adults aged 50 to 64 with arterial stiffness who ate black beans, whole wheat kernels or white rice. Systolic pressure rose 4% after white rice but not after beans or wheat, and arterial stiffness fell only after wheat, not beans. Canadian Pacific Kansas City and the St. Boniface Hospital Foundation funded it.
Eating ¾ cup of black beans lowered measures of blood vessel tone 6 hours later compared with rice and some other beans
Single-blind pilot crossover trial in 8 healthy adults who ate ¾ cup of black, navy, pinto or red kidney beans, or white rice, with measurements at 1, 2 and 6 hours. The darker beans, black and red kidney, did best, and LDL cholesterol was lower 6 hours after black beans than after rice. Only 8 people took part.
People who ate the most legumes had a 6% lower risk of dying from any cause than those who ate the least
Pooled legumes (beans, lentils, chickpeas and peas), not black beans alone. Meta-analysis of 32 cohorts with 1,141,793 people and 93,373 deaths. Stroke deaths were also lower, but heart disease and cancer deaths were not significantly changed. The authors rate the certainty of evidence low to moderate.
Eating four 100 g servings of legumes a week went with a 14% lower risk of ischemic heart disease
Pooled legumes, not black beans alone. Meta-analysis of 25 observational studies and 2 trial reports covering nuts and legumes in 501,791 people. Legumes were not significantly linked to stroke or diabetes, though only 2 studies covered diabetes.
People who ate the most legumes had a 10% lower risk of colorectal cancer
Pooled legumes, not black beans alone. Meta-analysis of 29 studies, 16 cohort and 13 case-control. A rise of 100 g a day went with a 21% lower risk. The authors call the evidence weak, and the links tended to fade in analyses adjusted for other factors.
US adults who ate beans had a 22% lower risk of being obese
Analysis of US national survey data (NHANES 1999 to 2002) with 1,475 adults, based on a single 24-hour diet recall. Bean eaters also had a smaller waist (23% lower risk of an increased waist size) and ate more fiber, potassium, magnesium and iron. Beans here are not limited to black beans, and a link is not proof of cause.
People who raised their dry bean intake the most had 65% lower odds of an advanced colorectal adenoma returning
Analysis of the Polyp Prevention Trial cohort, comparing the top quarter of increase in dry bean intake (a median 370% above baseline) with the bottom quarter. There was no link for nonadvanced adenomas. Dry beans are covered as a group, not black beans alone.
The black coat of black beans holds mostly delphinidin anthocyanins, with smaller amounts of petunidin and malvidin
Lab analysis of four black bean varieties grown in four places in Canada. The pigment sat in the outer layer of the seed coat, and the inner layer held condensed tannins instead. It measured chemistry, not effects in people.
Boiling and steaming sharply reduced the anthocyanins in black beans, and steaming kept more total phenolics than boiling
Lab study of pinto and black beans cooked by boiling or steaming at normal and high pressure. Every method lowered total phenolics, tannins and antioxidant activity compared with raw beans. It measured chemistry, not health effects.
Cooking Tolosa black beans raised the bioaccessibility of their polyphenols in a digestion model
Lab study of five populations of this Spanish black bean, raw, cooked and as hummus, using simulated digestion and human intestinal cells. Cooking also raised antioxidant activity and had a positive effect on cell viability. It tested chemistry and cells, not people, and it points the opposite way from the loss of anthocyanins in cooking above.
Mice fed black or navy bean flour had less inflammation but more gut damage in chemically induced colitis
Study in mice, not people. Mice ate a diet with 20% cooked navy or black bean flour for 2 weeks before 7 days of dextran sulphate to induce colitis. Bean diets raised short-chain fatty acids and lowered inflammatory signals in the colon and blood, but also increased colon injury scores and cell death. The authors say more research is needed.
Mice fed navy or black bean diets before colitis had milder inflammation and better markers of gut barrier repair
Study in mice, not people. Mice ate 20% cooked navy or black bean diets for 3 weeks, then a plain diet 24 hours before 5 days of dextran sulfate to induce colitis. The design mimics a relapse of disease, so it does not show what beans do during active colitis.
Rats fed cooked black beans had less body fat even on a high-fat, high-sugar diet
Mostly a rat study, with a short test of glucose, insulin and incretin responses in healthy people that the abstract does not quantify. Black beans lowered rat blood glucose, insulin and leptin, raised energy expenditure, and increased Clostridia bacteria and stool butyrate. Rat results may not carry over to people.
Who should be careful with black beans
Most people can eat black beans freely. Take a little care if one of these applies:
- Irritable bowel syndrome or a gassy gut. Monash University says legumes are naturally high in galacto-oligosaccharides (GOS), and that canned beans, or beans boiled and drained, tend to be lower in FODMAPs because some of these sugars leach into the water. Check serving sizes in the Monash app, and start small.
- Undercooked dry beans. The FDA says the lectin phytohaemagglutinin occurs in many bean species, most of all in red kidney beans, and advises soaking kidney beans, discarding the water and boiling them for at least 30 minutes, not using a slow cooker. Boiling dry black beans the same way is a safe habit, and canned beans are already cooked.
- Salt limits. USDA data list 384 mg of sodium per 100 g for canned black turtle beans, against about 1 mg in boiled beans cooked without salt. Draining and rinsing lowers it (218 mg in the USDA entry for canned black beans drained and rinsed).
How to choose, store and eat black beans
- Cooked from dry: a cup of boiled beans has 15 g of fiber and 15.2 g of protein. Lab tests found boiling and steaming both cut the anthocyanins in black beans, and steaming kept more total phenolics.
- Canned: a cup (180 g) a day of canned beans, with black as one of five types, lowered LDL cholesterol by about 8% in 4 weeks. Drain and rinse them to cut the salt.
- With rice: black beans with rice lowered the blood sugar rise after a meal compared with rice alone in two small trials, in 17 adults with type 2 diabetes and in 12 healthy women.
Dry beans keep a long time in a cool, dry place, but older beans lose flavor and take longer to cook. Many cooks soak them for several hours, which shortens cooking time and removes some gas-producing sugars, and then pour the soaking water away before boiling in fresh water.
Sources
- Including legumes on a low FODMAP diet. Monash FODMAP blog. 2016.
- Bad Bug Book, second edition: phytohaemagglutinin (kidney bean lectin). US Food and Drug Administration.
- Winham DM, Hutchins AM. Perceptions of flatulence from bean consumption among adults in 3 feeding studies. Nutr J. 2011.
- Doma KM, Dolinar KF, Dan Ramdath D, Wolever TMS, Duncan AM. Canned beans decrease serum total and LDL cholesterol in adults with elevated LDL cholesterol in a 4-wk multicenter, randomized, crossover study. J Nutr. 2021.
- Thompson SV, Winham DM, Hutchins AM. Bean and rice meals reduce postprandial glycemic response in adults with type 2 diabetes: a cross-over study. Nutr J. 2012.
- Winham DM, Hutchins AM, Thompson SV. Glycemic response to black beans and chickpeas as part of a rice meal: a randomized cross-over trial. Nutrients. 2017.
- Xu B, Chang SK. Total phenolic, phenolic acid, anthocyanin, flavan-3-ol, and flavonol profiles and antioxidant properties of pinto and black beans (Phaseolus vulgaris L.) as affected by thermal processing. J Agric Food Chem. 2009.
- Beans, black turtle, mature seeds, canned. USDA FoodData Central (SR Legacy).
- Beans, black, canned, sodium added, drained and rinsed. USDA FoodData Central (Foundation Foods).
- Common bean. Wikipedia.
History of black beans
The common bean was domesticated twice, independently, in Mesoamerica and in the southern Andes, roughly 8,000 years ago. Genome work that compared 60 wild plants and 100 landraces confirmed two separate domestications from gene pools that had split before people arrived, and sequence data point to central Mexico as the species’ place of origin.
The black turtle bean is a small, shiny variety whose name refers to its hard outer shell. In Spanish it is frijol negro, and in Portuguese feijão preto. Anthocyanins in the dried seed coat give it its color.
Beans reached Europe after 1492. A 2023 genome study found that the first common beans to succeed there were Andean types, introduced after Francisco Pizarro’s expedition to northern Peru in 1529, and that hybridization between Andean and Mesoamerican types helped the crop adapt to Europe’s climate. Beans grown in Europe before then were unrelated to the New World Phaseolus beans.
In Latin America black beans became a staple. Cuban black bean soup is traditionally served with white rice, black beans are required in the Costa Rican and Nicaraguan dish gallo pinto, and they are fundamental to Venezuela’s pabellón criollo. In Brazil they are the base of feijoada, a bean and meat stew often called the national dish.
A popular story credits enslaved Africans in colonial Brazil with inventing feijoada from black beans and leftover pork. The story is disputed. Critics say it idealizes slavery, and regional Portuguese versions of the dish, which Wikipedia links to meat stews going back to Roman cuisine, do not use black beans at all, since the beans are American.
Sources
- Schmutz J, McClean PE, Mamidi S, et al. A reference genome for common bean and genome-wide analysis of dual domestications. Nat Genet. 2014.
- Bitocchi E, Nanni L, Bellucci E, et al. Mesoamerican origin of the common bean (Phaseolus vulgaris L.) is revealed by sequence data. Proc Natl Acad Sci U S A. 2012.
- Bellucci E, Benazzo A, Xu C, et al. Selection and adaptive introgression guided the complex evolutionary history of the European common bean. Nat Commun. 2023.
- Common bean. Wikipedia.
- Black turtle bean. Wikipedia.
- Feijoada. Wikipedia.
Frequently asked questions about black beans
Are black beans good for you?
For most people, yes. A cup of boiled black beans (172 g) has 15 g of fiber, 15.2 g of protein and 64% of the daily value for folate, for 227 calories. A bean mix that included black beans lowered LDL cholesterol by 0.21 mmol/L in 6 weeks, and pooled pulse trials found a 0.14 mmol/L drop. Most black bean trials are small meal tests, so the benefits are modest and not fully proven.
Are black beans high in protein?
Yes, for a plant food. Boiled black beans have 15.2 g of protein per cup (172 g) and 8.86 g per 100 g, about 30% of their calories. They score 100 out of 100 for essential amino acids on this site’s protein check, which is a calculation from nutrient data and not a trial result.
Are black beans good for weight loss?
No trial here tested black beans for weight loss. In a meta-analysis of 21 trials, diets with about one serving a day of pulses (132 g) led to 0.34 kg more weight loss over a median of 6 weeks, a small effect. In 35 older adults, a breakfast with 135 g of black beans kept people about as full as one with beef. A cup has 227 calories and 15 g of fiber.
Do black beans lower cholesterol?
Probably a little, based on bean studies that included black beans. A 120 g a day bean mix that included black beans lowered LDL by 0.21 mmol/L in 6 weeks, and 1 cup (180 g) a day of canned beans lowered it by about 8% in 4 weeks, while half a cup did not differ from rice. No trial tested black beans alone for cholesterol.
Are black beans good for people with diabetes?
They can fit, but the evidence is small. Black beans with rice lowered the blood sugar rise after a meal compared with rice alone in 17 adults with type 2 diabetes and in 12 healthy women. Pooled pulses lowered fasting glucose across 41 trials, though results varied widely. Portions and medicines matter, so check with your care team.
Are canned black beans as healthy as dried?
Both work, with one difference. The canned bean trial lowered LDL cholesterol by about 8%, with black as one of five beans. USDA data list 384 mg of sodium per 100 g for canned black turtle beans against about 1 mg for boiled beans cooked without salt, and 218 mg once drained and rinsed. Monash adds that canned beans tend to be lower in FODMAPs.
Do black beans cause gas?
They can in some people, and no trial here measured gas from black beans. Monash says legumes are high in GOS, and canned or boiled and drained beans tend to be lower. In three feeding studies of pinto beans, baked beans and black-eyed peas, fewer than half of adults reported more gas in the first week, and 3 to 11% did so even on control foods.
Do you need to soak black beans?
Many cooks do, but it is a choice. Soaking shortens cooking time and removes some gas-producing sugars, and the soaking water should be poured away. Either way, dry beans should be boiled until soft: the FDA’s advice for kidney beans is a boil of at least 30 minutes, and the toxin behind it occurs in many bean species.