Kidney Beans: Nutrients, What Research Shows and Safety

Kidney beans are the seeds of the common bean plant, Phaseolus vulgaris (pea family). They are sold dried, canned or cooked, and the best known kind is the dark red bean used in chili, rice dishes and salads. People eat them for fiber, plant protein and folate. This page covers the whole bean as food. It keeps cooking safety first, and keeps the food apart from extracts and supplements made from beans.

Read this first

• Food safety first. Raw or undercooked red kidney beans contain a lectin called phytohaemagglutinin (PHA). Health Canada says most reported illnesses involved undercooked red kidney beans, with nausea, vomiting and diarrhea starting about 1 to 3 hours after eating. [1]
• Dried beans need proper cooking. The FDA advises soaking for at least 5 hours, then boiling in fresh water for at least 30 minutes. [2] Health Canada gives a shorter boil of at least 10 minutes after the same soaking. [1] Sources differ, so see "Choosing, storing and food safety" below. Do not cook dried kidney beans in a slow cooker. [1]
• Canned kidney beans are already cooked. The FDA says the low PHA levels in canned and properly cooked beans will not affect you. [2]
• Evidence in one line: pooled trials of beans and other pulses show a small drop in LDL cholesterol, and eating beans is linked to better heart health in observational studies. Studies on kidney beans alone are scarce in what we read. [3] [4]
• Allergy: we did not read a source on kidney bean allergy. For trouble breathing or swelling of the face or throat after any food, call 911 (or your local emergency number). [5]

What is in it (USDA values)

The main columns are for red kidney beans, mature seeds, boiled without salt (USDA FoodData Central item 175194, SR Legacy) [6]. The serving is the USDA household portion of 1 cup cooked (177 g). The last column is the same bean dry and uncooked (item 175193) [7]; do not compare it with the cooked columns, because cooking adds water. The USDA raw item is "all types" of kidney beans and the cooked item is red kidney beans, boiled without salt. Canned beans, which usually contain salt, are a different product with different values.

% Daily Value uses the FDA 2016 Daily Values; the cup column is the 100 g value multiplied by 1.77. USDA lists no Daily Value for energy or sugars. Values vary with variety, growing place and cooking time. A dash means USDA has no value.

Plant compounds: the one measured in kidney beans by the sources we read is PHA. A 2025 laboratory study estimated that dark red kidney beans hold about 223 mg of active PHA per gram of dry bean, and that commercially canned beans had more than 99% less. [8] The same sources describe PHA as a poison when beans are raw or undercooked, not a benefit. Beans also contain resistant starch and sugars called oligosaccharides that gut bacteria ferment; this causes gas in some people. [4] Phytic acid, tannins and lectins in legumes can reduce mineral absorption, and soaking, germination and fermentation lower them. [9] We did not find a measure of how much this matters in a mixed diet.

What research says

Eaten as food vs taken as an extract. The trials in the table used cooked pulses as food. Most were small or short. The abstracts we read did not say who funded them. Observational findings show an association, not proof that beans cause the difference.

How much is a normal serving

The USDA household portion is 1 cup of cooked kidney beans (177 g), with about 225 kcal, 15.3 g of protein and 13.1 g of fiber (see the table). [6] 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. [16] Trials in the cholesterol analysis used a median of about 130 g of pulses a day. [3] This is information, not a prescription; your own needs depend on your health and your care team.

Safety, allergy and medicines

• Raw or undercooked beans (lectin poisoning). PHA is a lectin found at high levels in raw red kidney beans. Health Canada lists extreme nausea first, then vomiting and diarrhea, sometimes belly pain, usually 1 to 3 hours after eating; hospital treatment is rarely needed and symptoms pass fairly quickly. [1] The 2018 French outbreak had a median incubation of 3.3 hours, and the chili held PHA above the potentially toxic dose (400 hemagglutinating units per gram) while the raw beans measured 66,667 units per gram. [15]
• How little it takes. The Australian Food Safety Information Council says as few as four or five raw beans can cause severe stomach ache, vomiting and diarrhea. [17] A 2025 laboratory paper cites reports that four or five soaked raw dark red kidney beans can cause food poisoning. [8]
• Slow cookers. Health Canada says slow cookers do not get hot enough to destroy lectins and should not be used for dried red kidney beans. [1] The Australian council warns that low-temperature cooking may not destroy the toxin, and that badly cooked beans can be more toxic than raw ones. [17]
• If someone gets sick after eating beans: see the poisoning: what to do first page. For severe symptoms or a young child who is very unwell, call your local emergency number.
• Digestion. Resistant starch and oligosaccharides ferment in the colon and can cause gas, bloating and cramping in some people. [4] In three feeding studies of pinto beans, black-eyed peas and baked beans (kidney beans were not tested), fewer than half of people noticed more gas with pinto or baked beans in the first week, and the authors concluded concern about gas may be exaggerated. [18]
• Allergy: the sources we read for this page do not describe kidney bean allergy. Food allergy can cause hives, swelling and trouble breathing; anaphylaxis is a medical emergency, call 911. [5] See food allergy basics and emergency signs.
• Kidney disease, medicines, pregnancy, children: USDA lists 713 mg of potassium and 251 mg of phosphorus in a cup of cooked kidney beans (15% and 20% of the Daily Value). [6] We did not read a source on beans and kidney disease limits, warfarin (cooked kidney beans have 12% of the vitamin K Daily Value per cup), or pregnancy. See foods, kidney disease, potassium and oxalates, food and medicine interactions and foods in pregnancy, and ask a clinician.

Choosing, storing and food safety

• Dried beans: the FDA says to soak at least 5 hours, then boil in fresh water for at least 30 minutes. [2] Health Canada says soak in 2 to 3 times the volume of water for at least 5 hours, discard the soaking water, then boil vigorously for at least 10 minutes. [1] The Australian council also gives soaking for at least 5 hours and a brisk boil of at least 10 minutes in fresh water. [17] The sources differ on boiling time; the FDA figure is the longer one.
• Canned beans can be eaten without further cooking. [1] [17] A 2025 laboratory study found commercially canned beans had more than 99% less active PHA than dry dark red kidney beans. [8] We did not read a source on the sodium in canned beans; see dried vs canned beans, soaking and sodium.
• Sprouted or raw bean products: see raw sprouts and undercooked foods for the risks the site covers.

Related pages

• Lectins in beans: cooking dried beans safely
• Dried vs canned beans, soaking and sodium
• Beans, gas, FODMAP and digestion
• Black beans
• Pinto beans
• Legumes as food: what trials found
• Foods for cholesterol and heart health