Tepary Beans: Nutrients, What Research Shows and Safety
Tepary beans as a food: composition from peer-reviewed sources (USDA has no item), very high raw lectin activity, why they must be soaked and well cooked, and the limited research.
Content last updated . This page has not been medically reviewed.
Tepary beans are the small, flat seeds of Phaseolus acutifolius, a bean plant of the pea family and a different species from the common bean. The seeds come in white, yellow and black-seeded types, and the white and yellow kinds were among the traditional foods of the Pima people of the southwestern United States. [1] [4] They are eaten dried and cooked in stews, soups and with whole grains. [1] This page separates the bean as food from lab studies of its proteins. It puts safety first, because the one reference source we read describes its raw lectin activity as exceptionally high. [1]
Read this first
- Never eat tepary beans raw or undercooked. The PROTA plant reference says tepary lectin activity is "exceptionally high" but readily reduced by cooking; raw tepary flour caused death in mice and rats, and soaking and cooking the seeds removed that toxicity completely. [1] That is animal evidence, not a report of human poisoning. We read no human poisoning report for tepary beans.
- No tepary-specific cooking time was found. PROTA says to soak and cook thoroughly and notes dry seeds can take a long time to cook. [1] The FDA's steps for beans (soak at least 5 hours, boil in fresh water at least 30 minutes) are the longest published figures we read; they are not written for tepary beans. [2] Follow your national food-safety authority.
- USDA has no item for tepary beans. The numbers below come from a plant reference and a lab paper, not from the USDA database, and they differ between sources.
- Evidence in one line: we found no trial of tepary beans in people. Pooled trials of pulses as a group show small benefits for cholesterol, which is not specific to this bean. [7]
- Allergy: we read no source on tepary bean allergy. For trouble breathing or swelling of the face or throat after any food, call 911 (or your local emergency number). [11]
What is in it (USDA values)
USDA FoodData Central has no item for tepary beans, so there are no USDA values to give. We use the PROTA plant reference's values for dry seeds [1] and a 2021 laboratory paper on flour milled from raw and cooked tepary beans [3]. These are dry-weight figures for the uncooked bean or its flour, so they are not comparable with cooked-bean tables on other pages. We did not invent or convert any value.
| Nutrient | Dry seed, per 100 g (PROTA) [1] | % Daily Value of 100 g dry (our calculation) | Raw flour / cooked flour, % dry basis [3] |
|---|---|---|---|
| Energy | 353 kcal (1478 kJ) | no DV | not given |
| Protein | 19.3 g | 39% | 23.46% / 25.27% |
| Fat | 1.2 g | 2% | not given |
| Carbohydrate | 67.8 g | 25% | not given |
| Fiber | 4.8 g | 17% | 2.96% / 2.44% (dietary fiber) |
| Calcium | 112 mg | 9% | not given |
| Phosphorus | 310 mg | 25% | not given |
| Thiamin (B1) | 0.33 mg | 28% | not given |
| Riboflavin (B2) | 0.12 mg | 9% | not given |
| Niacin (B3) | 2.8 mg | 18% | not given |
| Vitamin C | 0 mg | 0% | not given |
% Daily Value uses the FDA 2016 Daily Values and is our arithmetic on the PROTA figures; 100 g dry beans is more than a usual serving. The two sources disagree on protein and fiber, which fits natural variation between varieties, growing places and methods. Sulfur-containing amino acids (methionine and cysteine) are low, as in other pulses, and were the limiting amino acids in the 2021 paper. [1] [3] In that paper the protein was digested less well raw (about 48 to 50% in the lab test) than cooked (about 62 to 64%). [3]
Plant compounds: tepary beans contain trypsin inhibitors, gas-causing oligosaccharides and phytic acid at levels PROTA calls similar to cowpea and chickpea, and it says cyanogenic glucosides have not been detected. [1] A 2021 paper reports roughly 110 mg gallic acid equivalents of polyphenols per 100 g, quoted from another source. [3]
What research says
| Health goal | What the sources found | Strength of evidence | What was studied |
|---|---|---|---|
| Blood sugar after meals | In 1990, eight healthy volunteers ate 25 g carbohydrate portions of six traditional Pima foods, including white and yellow teparies. All calculated glycemic indices were low (16 to 40 on a scale where glucose is 100). The abstract gives no separate tepary figure. [4] | Insufficient evidence for tepary beans in particular | Small crossover meal test in healthy people, not people with diabetes |
| Cholesterol, weight, diabetes | Pooled randomized trials of pulses as a group found an LDL drop of 0.17 mmol/L at about 130 g a day [7] and 0.34 kg more weight loss over about 6 weeks [9]; Harvard calls the evidence on diabetes mixed. [8] None of the trials we read is listed as testing tepary beans. | Promising but limited for pulses; no tepary-specific evidence read | Randomized trials, mixed pulses |
| Protein quality | Flour from cooked beans scored higher than raw flour on lab digestibility and a calculated protein quality score; the authors call the cooked samples medium-quality protein. [3] | Lab only | Flour and protein concentrate, laboratory tests |
| Lectin extracts and cells | A 2025 study of a lectin-rich seed protein extract found it damaged small intestinal cells in lab tests (IC50 10.08 and 108.91 micrograms per mL) and showed genotoxic damage at 48 hours in mice at 1000 mg/kg, but no deaths in an acute mouse test. [5] | Lab or animal only (a safety signal, not a benefit) | Protein extract, cells and mice, not whole cooked beans |
| Any disease treatment or prevention | Proper evidence not found in the sources we read. | No good evidence of benefit | None |
Eaten as food vs lab extracts. The glycemic test and the pooled trials involved food. The 2021 and 2025 papers used flours, protein concentrates and extracts, and the 2025 extract was not cooked, so do not read its results as what cooked beans do. The 2021 paper was funded by a Mexican university program and the authors declared no conflicts. [3]
How much is a normal serving
USDA lists no household portion for tepary beans. The NHS counts 80 g of beans and pulses as one portion and says they count only once a day toward 5 A DAY, however much you eat. [6] We did not find a tepary-specific serving. This is information, not a prescription.
Safety, allergy and medicines
- Raw or undercooked beans. PROTA reports exceptionally high lectin activity that cooking greatly reduces, and death in mice and rats fed raw flour that did not occur after soaking and cooking. [1] The 2025 extract study found no deaths in mice at the doses used, so animal findings differ by material. [5] For beans in general, the FDA says PHA in raw or undercooked beans can cause nausea, severe vomiting and diarrhea. [2] Health Canada names red kidney beans as the main concern but says lectins occur in many legumes. [10] Harvard says raw beans simmered at low heat, as in a slow cooker, will not lose all their lectins. [12]
- Hard seeds, long cooking. PROTA says dry tepary seeds become very hard in storage and take a long time to cook, and that white-seeded types cook faster than black-seeded ones. [1] Undercooking is the risk, so cook until fully soft.
- Digestion. PROTA lists flatulence among the barriers to wider use. [1] Harvard describes gas from fermentable carbohydrates in legumes generally. [8] A hospital low-FODMAP leaflet names beans and pulses as the main source of galacto-oligosaccharides and says the restriction is temporary. [13] See beans, gas, FODMAPs and digestion.
- Allergy: we read no source on tepary bean allergy. Anaphylaxis is a medical emergency, call 911. [11] See food allergy basics and emergency signs and legume allergy and cross-reactivity.
- Kidney disease, medicines, pregnancy, children: we read no source on these for tepary beans and no USDA potassium value. See foods, kidney disease, potassium and oxalates, food and medicine interactions and foods in pregnancy, and ask a clinician.
- If someone gets sick after eating beans: see poisoning: what to do first.
Choosing, storing and food safety
- Cooking: soak, drain, then boil in fresh water until fully soft. PROTA says soaking and cooking removed the reported toxicity. [1] The FDA's published bean steps are a 5-hour soak and a 30-minute boil; Health Canada's 10-minute boil is for red kidney beans. [2] [10] We do not extend either to tepary beans; use your national authority's advice and do not rely on a slow cooker for dry beans. [10] [12]
- Buying: tepary beans are often a specialty item. We read nothing about quality grades or storage beyond PROTA's note on hardening.
- Flour or ground beans: a lectin-rich raw flour is what caused deaths in the animal study. [1] Cook the beans before grinding for food.
Related pages
Health connections for Tepary Beans
What research links to eating or drinking this food, and how strong the evidence is. Many studies are observational or use juice, powder, oil or extracts rather than the food as eaten; each card says which.
Tepary beans as a source of protein
Established rolePROTA lists 19.3 g protein, 4.8 g fiber and 353 kcal per 100 g dry seed; a 2021 lab paper found 23.46% protein in raw flour and 25.27% in cooked flour (dry basis), with sulfur amino acids limiting.
Supplements: Food source only.
Tepary beans and blood sugar after meals
Not enough evidenceIn 1990, eight healthy volunteers ate six traditional Pima foods, including white and yellow teparies. All glycemic indices were low (16 to 40); the abstract gives no separate tepary value.
Supplements: Not applicable.
tepary beans and cholesterol, blood sugar or weight
Not enough evidencePooled randomized trials of pulses as a group found a small LDL drop (0.17 mmol/L), lower fasting glucose and insulin, and 0.34 kg more weight loss. We read no trial that lists tepary beans.
Supplements: Not applicable.
Cooked vs raw tepary protein digestibility
Lab or animal research onlyIn a 2021 lab paper, protein digestibility was about 48 to 50% in raw flour samples and 62 to 64% in cooked ones, and a calculated protein quality score was higher in cooked flour.
Supplements: Not applicable.
Tepary lectin extract in cells and mice
Lab or animal research onlyA 2025 study of a lectin-rich seed protein extract found it cytotoxic to small intestinal cells and genotoxic in mice at 48 hours, with no deaths in an acute mouse test. It used an extract, not cooked beans.
Supplements: Not applicable.
Connected topics
Open a group to see how each topic connects and how strong the evidence is.
Body systems (2)
- Digestive SystemDocumented risk
Raw tepary beans have very high lectin activity per the plant reference and gas-causing sugars; cooking reduces the lectin, and gas is common with beans.
- Gut HealthDocumented risk
Raw tepary beans have very high lectin activity per the plant reference and gas-causing sugars; cooking reduces the lectin, and gas is common with beans.
Body parts (1)
- GutDocumented risk
Raw tepary beans have very high lectin activity per the plant reference and gas-causing sugars; cooking reduces the lectin, and gas is common with beans.
Conditions & symptoms (3)
- FlatulenceDocumented risk
Beans contain carbohydrates that gut bacteria ferment; gas and bloating are common.
- Food PoisoningDocumented risk
The plant reference reports high raw lectin activity and deaths in mice and rats fed raw flour, removed by soaking and cooking. No human poisoning report was read; the FDA describes PHA poisoning for raw or undercooked beans in general.
- Irritable Bowel SyndromeDocumented risk
A hospital low-FODMAP leaflet for adults with IBS-type symptoms names beans and pulses as the main source of galacto-oligosaccharides and asks to limit them temporarily, usually 4 to 6 weeks.
Documented risks and interactions (3)
- Raw tepary beans and lectin toxicity. PROTA says tepary lectin activity is exceptionally high but readily reduced by cooking; raw flour killed mice and rats, and soaking and cooking the seeds eliminated the toxicity. We read no human poisoning report.
- Gas, bloating and FODMAPs. PROTA lists gas-causing oligosaccharides in tepary seeds and flatulence as a barrier to wider use. People on a low-FODMAP plan are usually asked to limit beans for a short time with a dietitian.
- Legume allergy emergency signs. We read no source on tepary bean allergy. Food allergy can cause hives, swelling and trouble breathing; anaphylaxis is a medical emergency, so call 911 or your local emergency number.
Frequently asked questions
Are tepary beans safe to eat?
Yes when soaked and well cooked. PROTA says raw tepary flour killed mice and rats but soaking and cooking removed the toxicity. [1] Never eat them raw, and we found no human poisoning report.
How long do I boil tepary beans?
We found no tepary-specific time. The FDA gives a 5-hour soak and 30-minute boil for beans, Health Canada a 10-minute boil for red kidney beans. [2] [10] Check your national authority and cook until fully soft.
Are tepary beans good for blood sugar?
A 1990 test in eight healthy people found low glycemic indices for six traditional Pima foods including teparies, but gave no separate tepary figure. [4] That is not proof of a benefit for people with diabetes.
Why are there no USDA numbers?
The USDA database does not list tepary beans. We used a plant reference and a lab paper instead. [1] [3]
Do tepary beans cause gas?
PROTA lists flatulence-causing oligosaccharides in tepary seeds. [1]
References
- PROTA (Plant Resources of Tropical Africa), via PlantUse. Phaseolus acutifolius (PROTA)). No date shown. Read 2026-10-24.
- U.S. Food and Drug Administration. Natural Toxins in Food. Content current as of 2024-09-26. Read 2026-10-24.
- López-Ibarra C et al. Protein concentrates on tepary bean (Phaseolus acutifolius Gray) as a functional ingredient: in silico docking of tepary bean lectin to peroxisome proliferator-activated receptor gamma. Front Nutr 2021;8. Read 2026-10-24.
- Brand JC, Snow BJ, Nabhan GP, Truswell AS. Plasma glucose and insulin responses to traditional Pima Indian meals. Am J Clin Nutr 1990;51(3):416-420 (abstract read via Europe PMC). Read 2026-10-24.
- Valadez-Vega C et al. Assessment of genotoxicity and cytotoxicity of tepary bean (Phaseolus acutifolius) seed protein extract. Life (Basel) 2025;15(12):1937 (abstract read via Europe PMC). Read 2026-10-24.
- NHS. 5 A DAY: what counts?. Last reviewed 9 June 2026. Read 2026-10-24.
- Ha V et al. Effect of dietary pulse intake on established therapeutic lipid targets for cardiovascular risk reduction: a systematic review and meta-analysis of randomized controlled trials. CMAJ 2014 (abstract read via Europe PMC). Read 2026-10-24.
- Harvard T.H. Chan School of Public Health. The Nutrition Source: Legumes. No update date shown on the page. Read 2026-10-24.
- Kim SJ et al. Effects of dietary pulse consumption on body weight: a systematic review and meta-analysis of randomized controlled trials. Am J Clin Nutr 2016 (abstract read via Europe PMC). Read 2026-10-24.
- Health Canada. Lectins in Dry Legumes. Page details dated 2017-05-04. Read 2026-10-24.
- MedlinePlus. Food allergy. Last updated 19 November 2025. Read 2026-10-24.
- Harvard T.H. Chan School of Public Health. Lectins (The Nutrition Source). Last reviewed January 2022. Read 2026-10-24.
- Cambridge University Hospitals NHS Foundation Trust. Low FODMAP diet: reducing fermentable carbohydrates in your diet. Patient leaflet approved 14 Aug 2025. Read 2026-10-24.