Cranberry beans are speckled, but not for long. Dried, they are tan or creamy with splashes of red, magenta or black, and after cooking the specks vanish and the beans take on a more even, darker color. They are a variety of the common bean, Phaseolus vulgaris, the same species as pinto, kidney and black beans, and they are also sold as borlotti and Roman beans.
The creamy background changes with time as well. Plant scientists link the browning of stored cranberry and pinto beans to proanthocyanidins in the seed coat, which oxidize after harvest. Breeders have developed non-darkening lines, and one of them was bred from a landrace named Wit-rood boontje.
Cooked, a cup (177 g) has 16.5 g of protein, 15.2 g of fiber and 92% of the daily folate for 241 calories. Few studies have tested cranberry beans in people, so most of the research below uses other common beans, pooled pulses or lab methods, and each card says what was tested.
Health benefits of cranberry beans
The top findings from 10 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 →- ★★Slightly lower “bad” LDL cholesterol, from pulsesA median of 130 g a day of pulses (beans, chickpeas, lentils and peas) lowered LDL a little (by 0.17 mmol/L across 26 trials). That is about one serving, and cranberry beans were not tested alone.
- ★Smaller blood sugar rise than rice or pastaIn healthy volunteers, a quarter or half cup of cranberry beans cut the blood sugar response by 20% or more against rice, pasta and potato. It was not lower than the response to corn.
- ★Gas in fewer than half eating other beansThree trials tested half a cup a day of pinto beans, baked beans or black-eyed peas, not cranberry beans. Fewer than half reported more gas in the first week, and 3 to 11% did even on control diets.
- ★Little iron absorbed from common beansIn 29 healthy young adults, about 0.4% of the iron in 100 g of cooked common beans was absorbed, also in an iron-targeted line. In 20 women, specially bred low-phytic-acid lines of common beans (not cranberry) gave 50 to 60% more absorbed iron than their normal parent lines.
All 10 studies, strongest evidence first
About a daily serving of pulses lowered LDL cholesterol by 0.17 mmol/L in trials of pooled pulses
Pooled pulses (beans, chickpeas, lentils and peas), not cranberry beans alone. Meta-analysis of 26 randomized trials (1,037 people) lasting at least 3 weeks, in which a median of 130 g a day (about 1 serving) replaced other foods. Apolipoprotein B and non-HDL cholesterol did not change, and the authors call for longer, higher-quality trials.
A quarter or half cup of cranberry beans cut the blood sugar response by 20% or more compared with rice, pasta and potato, but not compared with corn
Trials in healthy volunteers (24 people at one-quarter cup, 18 at one-half cup) compared six kinds of beans, cranberry among them, with corn, rice, pasta and potato, measuring blood glucose for 2 hours. Across all six beans the response averaged about 53% and 56% of the controls at the two doses. Grower groups from Ontario, Manitoba and Alberta and Agriculture and Agri-Food Canada funded it.
In three feeding studies of half a cup of beans a day, fewer than half of people reported more gas in the first week
Pinto beans, baked beans and black-eyed peas, not cranberry beans. Two randomized crossover trials (17 and 29 people, 8-week phases) and one trial of 40 people eating pinto beans against 40 on a control soup for 12 weeks. Only 19% reported more gas with black-eyed peas, and 3 to 11% reported more gas even on control diets.
Iron absorption from 100 g of cooked common beans was only about 0.4%, and a bean line targeted for higher iron did not change it
Common beans, not cranberry beans. 29 healthy young adults ate 100 g of one of two cooked common bean lines labeled with a stable iron isotope, and absorption was 0.409% against 0.407%. The authors say the extra iron in the targeted line was probably too small to help.
Common beans bred to have less phytic acid gave 50 to 60% more absorbed iron than their normal parent lines
Common beans, not cranberry beans. In 20 women, iron absorption from two low-phytate bean lines was 6.1% and 4%, and each was 50 to 60% higher than from its normal-phytate parent line, measured with stable iron isotopes in a crossover design. These were specially bred lines, not ordinary beans.
A diet with 20% cranberry bean flour reduced the severity of chemically induced colitis in mice
Mouse study using flour from two cranberry bean types, one that darkens and one that does not, against a basal diet, with colitis triggered by 2% dextran sodium sulfate for 7 days. The beans also raised short-chain fatty acids and lowered inflammatory signals, and both types worked alike. It is a proof of concept in mice, not an effect shown in people.
Cooked cranberry beans scored 0.82 for protein quality in lab digestion tests, among the highest of four pulses
Lab (in vitro) tests on cranberry beans, red kidney beans, cowpeas and pigeon peas before and after home cooking. The pulses held 20 to 26% protein, and cooking improved protein digestibility by about 14% on average, with a cooked average score of 0.81. No people or animals were tested, and the authors say the digestion assays need standardizing.
In the lab, digesting cooked borlotti beans released 20 times more polyphenols than home cooking, mostly through starch digestion
Lab study of borlotti beans, the Italian name for cranberry beans. Simulated digestion released 40.4 mg of polyphenols per gram against 2.22 mg per gram from home preparation. In a cell model of inflammation, extracts of cooked beans lowered mRNA for the inflammatory markers IL1β and iNOS by 25% and 40%. Cells, not people.
After pressure cooking and simulated digestion, only 8.75 to 14.69% of the phenolics in cranberry beans were bioaccessible
Lab study of a regular cranberry bean (8.75%) and a nondarkening one (14.69%). Total phenolics fell after cooking and digestion, but cooking released more of the bound ferulic and sinapic acids. Resistant and slowly digestible starch did not differ between the two types. No people or animals were tested.
A purified protein from cranberry beans blocked the starch-digesting enzyme amylase in rats, with no considerable rise in blood sugar or insulin
Rats were given 2 g of a test diet with or without 10 mg of an amylase inhibitor purified from cranberry beans. It was a purified protein, not whole cooked beans, and it was tested in rats, so it does not show what a plate of beans does in people.
Who should be careful with cranberry beans
Most people can eat cranberry beans freely once they are cooked. Take a little care if one of these applies:
- Raw or undercooked dried beans. Beans contain the lectin phytohemagglutinin, which the FDA says is found in many bean species and is highest in red kidney beans, where as few as four or five raw beans can cause severe nausea and vomiting within 1 to 3 hours. No source here gives levels for cranberry beans, which are the same species, so boil dried beans until fully tender and do not slow cook them raw. Canned beans are already cooked.
- Irritable bowel syndrome or a gassy gut. Monash University says legumes are naturally high in oligos such as galacto-oligosaccharides, and that canned legumes, or ones boiled and drained, tend to be lower in FODMAPs. It does not list cranberry beans on that page.
How to choose, store and eat cranberry beans
- Dried: the University of Maine guide gives about ¾ to 1 hour of cooking for cranberry beans after soaking, and 1 cup of dry beans makes 2 to 3 cups cooked. An overnight soak takes 6 to 8 hours in the fridge.
- Canned: already cooked. A drained 15½-ounce can equals about 1¾ cups of cooked dry beans, and Monash says draining and rinsing lowers FODMAPs.
- In meals: the blood sugar trial used ¼ and ½ cup servings of cooked beans, and both lowered the response compared with rice, pasta and potato.
Sort dried beans to remove stones, dirt and damaged or shriveled ones, and keep them in a cool, dry place in a resealable bag or tightly covered non-metal container for up to a year. Cooked beans keep 3 to 4 days in the fridge or up to 6 months in the freezer. Residues are a small concern: in EU testing in 2023, 3.5% of dried bean samples broke the legal limits after allowing for measurement uncertainty, mostly in beans from outside the EU, and EFSA rated the overall dietary risk from pesticide residues very low for most EU consumer groups.
Sources
- Phytohaemagglutinin (kidney bean lectin). Bad Bug Book, second edition. US Food and Drug Administration. 2012.
- Home food fact checker. UK Food Standards Agency.
- Including legumes on a low FODMAP diet. Monash FODMAP blog.
- How to store and cook dried beans. University of Maine Cooperative Extension. Updated 2025.
- Ramdath DD, Renwick S, Hawke A, Ramdath DG, Wolever TMS. Minimal effective dose of beans required to elicit a significantly lower glycemic response than commonly consumed starchy foods: predictions based on in vitro digestion and carbohydrate analysis. Nutrients. 2023.
- European Food Safety Authority, Carrasco Cabrera L, Di Piazza G, Dujardin B, et al. The 2023 European Union report on pesticide residues in food. EFSA J. 2025.
History of cranberry beans
Cranberry beans belong to the common bean, Phaseolus vulgaris, which was domesticated twice from wild plants in two separate places. Genome work on wild plants and landraces confirmed independent domestications from the Mesoamerican and Andean gene pools, which had split before people arrived. Less than 10% of the 74 Mb of DNA tied to domestication was shared by the two events.
According to Wikipedia, the cranberry bean was first bred in Colombia as the cargamanto. Common beans reached Europe after 1492, and a 2023 genome study found that the first ones to take hold there were of Andean origin, after Francisco Pizarro’s expedition to northern Peru in 1529. In a study of 307 European landraces, 67% were of Andean origin.
Italy gave the bean some of its names. Wikipedia describes borlotti as a variety of the cranberry bean bred in Italy to have a thicker skin, and saluggia beans as a regional borlotti named after Saluggia in northern Italy, where they have been grown since the early 1900s. The beans are also called Roman, romano and rosecoco beans, and Catarino beans in Portugal. They turn up in Italian, Portuguese, Turkish and Greek cooking.
Breeding goes on. In 2010 US Department of Agriculture scientists released Crimson, a maroon-speckled cranberry bean resistant to bean common mosaic virus and beet curly top virus, which yielded about 150 pounds more seed per acre than the commercial variety Capri in tests at 11 sites. Other breeders work on non-darkening lines that keep a pale background in storage.
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.
- 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.
- Angioi SA, Rau D, Attene G, et al. Beans in Europe: origin and structure of the European landraces of Phaseolus vulgaris L. Theor Appl Genet. 2010.
- Cranberry bean. Wikipedia.
- Freixas Coutin JA, Munholland S, Silva A, et al. Proanthocyanidin accumulation and transcriptional responses in the seed coat of cranberry beans (Phaseolus vulgaris L.) with different susceptibility to postharvest darkening. BMC Plant Biol. 2017.
- Erfatpour M, Pauls KP. A R2R3-MYB gene-based marker for the non-darkening seed coat trait in pinto and cranberry beans (Phaseolus vulgaris L.) derived from ‘Wit-rood boontje’. Theor Appl Genet. 2020.
- Bright new dry bean for salads and other foods. USDA Agricultural Research Service. 2010.
Frequently asked questions about cranberry beans
Are cranberry beans good for you?
For most people, yes, once they are cooked. A cup (177 g) has 16.5 g of protein, 15.2 g of fiber and 92% of the daily folate for 241 calories. Few studies tested cranberry beans in people: a quarter or half cup lowered the blood sugar response compared with rice, pasta and potato in healthy adults, while the LDL cholesterol result of 0.17 mmol/L comes from pooled pulses. None of the evidence here is strong.
Are cranberry beans the same as borlotti beans?
Mostly. Cranberry, borlotti and Roman beans are names for the same kind of speckled bean, though Wikipedia describes borlotti as a variety bred in Italy to have a thicker skin. All are the common bean, Phaseolus vulgaris, the same species as pinto, kidney and black beans. Lab studies of borlotti beans and of cranberry beans appear in the cards above.
Why do cranberry beans lose their color when cooked?
The red speckles vanish during cooking and the beans take on a more even, darker color, according to Wikipedia. No study here explains the cooking change itself. Separate plant research found that the creamy background of stored beans can brown as seed coat proanthocyanidins oxidize, and non-darkening lines exist.
Do you need to soak cranberry beans?
The University of Maine guide includes soaking in its steps for dry beans, with an overnight soak of 6 to 8 hours, and lists about ¾ to 1 hour of cooking for cranberry beans. It does not say whether you can skip soaking, and no study here tested it. Whatever you do, cook dried beans until fully tender.
Can you eat cranberry beans raw?
No. Raw and undercooked beans contain phytohemagglutinin, a lectin the FDA says is found in many bean species and is highest in red kidney beans, where four or five raw beans can cause severe nausea and vomiting within 1 to 3 hours. No source here gives cranberry bean levels, so treat them like kidney beans: boil dried beans until fully tender and do not slow cook them raw. Canned beans are already cooked.
Are cranberry beans high in protein?
Fairly high for a plant food. Cooked cranberry beans have 9.3 g of protein per 100 g, or 16.5 g in a cup (177 g), and protein supplies about 31% of their calories. The live nutrition data score the amino acid profile 100 out of 100 with no limiting amino acid, while a lab digestion test gave cooked cranberry beans a protein-quality score of 0.82, so how well it is digested matters too.
Do cranberry beans cause gas?
They can in some people, and no study here tested cranberry beans for gas. Monash University notes that legumes are naturally high in oligos such as galacto-oligosaccharides, and that canned or boiled and drained ones tend to be lower in FODMAPs. In three feeding studies of pinto beans, baked beans and black-eyed peas, fewer than half of people reported more gas in the first week of half a cup a day.
Are cranberry beans good for blood sugar?
They may fit, but the evidence is small. In healthy adults, a quarter or half cup of cranberry beans cut the blood sugar response by 20% or more compared with rice, pasta and potato, though not compared with corn. That trial did not test people with diabetes, so check portions and choices with your care team.