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Kidney beans

Phaseolus vulgaris

Also known as Red kidney bean, Rajma

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The large red-skinned variety of the common bean, and the one carrying the highest concentration of the toxic lectin phytohaemagglutinin when raw. The USDA reference entry is for the raw dry bean, which roughly triples in weight when boiled.

Heart HealthBlood Sugar & Metabolic HealthWeight Management

Potential health benefits

Best supported: Moderate

Ordered by how well the human research supports them — strongest first. A rating describes the state of the evidence, not how impressive the food is. How we rate evidence.

Blood lipid profile

Heart Health
Moderate evidence

Pooled analyses of pulse-feeding trials report modest LDL reductions when beans replace other foods in the diet, with kidney beans among the pulses included.

Moderate evidence. Several human studies point the same way, with real caveats.

4 sources

Deep research mode adds each paper’s own conclusion and stated limitations.

Blood glucose response

Blood Sugar & Metabolic Health
Insufficient evidence

Several trials report a low post-meal glucose response to kidney beans relative to refined starch, consistent with the wider pulse literature.

Insufficient evidence. Not enough human research to say anything useful yet.

No source is attached to this association yet, so it is rated insufficient by default. It is listed because people commonly ask about it — not because there is evidence for it.

Body composition

Weight Management
Insufficient evidence

White kidney bean extract is marketed as a starch blocker for weight loss. The trials are small, short, of poor quality and inconsistent, and none of this applies to eating cooked beans as food.

Insufficient evidence. Not enough human research to say anything useful yet.

1 source

Deep research mode adds each paper’s own conclusion and stated limitations.

Ask about Kidney beans

Ask about Kidney beans

Answers are written only from the entries on this page — the same nutrients, compounds, claims and citations you can read above. Nothing is added from outside the database, and every answer lists what it was built from.

AI explanations are not switched on for this site, so there is nothing to ask here. Everything above is read straight from the database and does not need them.

Key nutrients

Nutrient content per 100 grams
NutrientAmount% DV
Macronutrients
Calories337 kcal17%
Protein22.5 g45%
Total fat1.06 g1%
Carbohydrate61.3 g22%
Fibre15.2 g54%
Total sugars2.1 g—
Water11.8 g—
Fats
Saturated fat0.154 g1%
Monounsaturated fat0.082 g—
Polyunsaturated fat0.586 g—
Cholesterol0 mg0%
EPA (omega-3)0 g—
DHA (omega-3)0 g—
DPA (omega-3)0 g—
Linoleic acid (omega-6)0.228 g—
Vitamins
Vitamin A0 µg0%
Vitamin C4.5 mg5%
Vitamin D0 µg0%
Vitamin E0.21 mg1%
Vitamin K5.6 µg5%
Thiamin (B1)0.608 mg51%
Riboflavin (B2)0.215 mg17%
Niacin (B3)2.11 mg13%
Pantothenic acid (B5)0.78 mg16%
Vitamin B60.397 mg23%
Folate394 µg99%
Vitamin B120 µg0%
Choline65.9 mg12%
Minerals
Calcium83 mg6%
Iron6.69 mg37%
Magnesium138 mg33%
Phosphorus406 mg32%
Potassium1359 mg29%
Sodium12 mg1%
Zinc2.79 mg25%
Copper0.699 mg78%
Manganese1.11 mg48%
Selenium3.2 µg6%
Other measured compounds
Beta-carotene0 µg—
Alpha-carotene0 µg—
Lycopene0 µg—
Lutein + zeaxanthin0 µg—
Caffeine0 mg—
Ash3.37 g—

Nutrient values are per 100 g of the USDA reference entry named on this page and vary with variety, growing conditions, storage and preparation.

Source record: Beans, kidney, red, mature seeds, raw (USDA FoodData Central, FDC ID 173744).

% DV uses the FDA Daily Values for adults and children aged 4 and over. A dash means no Daily Value has been established for that nutrient.

Bioactive compounds

Compounds present in meaningful amounts. Presence is banded rather than quantified, because whole-food levels vary enormously with variety, growing conditions, storage and preparation.

How preparation changes things

Only effects with real support are listed. If a preparation method is missing, it is because nothing dependable is documented — not because it makes no difference.

  • boiledReduces phytohaemagglutinin

    A vigorous boil of at least ten minutes destroys phytohaemagglutinin. Temperatures below boiling, as in a slow cooker on low, can leave the lectin active or even more toxic than in the raw bean, which is why the boiling step is not optional.

  • soakedReduces oligosaccharides and phytate

    Soaking for several hours and discarding the water removes part of the gas-forming oligosaccharides and lowers phytate, in addition to shortening cooking time.

  • cookedIncreases resistant starch

    Cooking and cooling increases resistant starch through retrogradation, which is retained on reheating.

Things to know

Allergies, interactions and intake concerns. Every food gets this section — a reference where everything is uniformly good is not a reference.

  • Avoid

    Phytohaemagglutinin poisoning from undercooked beans

    Raw and undercooked red kidney beans cause acute vomiting and diarrhoea within a few hours, and as few as four or five raw beans have been enough. Dried beans must be soaked for at least five hours, the soaking water discarded, and the beans then boiled vigorously for at least ten minutes before simmering to tenderness. Slow cookers are the classic hazard, because temperatures below boiling can increase toxicity rather than reduce it. Canned kidney beans have already been heat-processed and are safe as sold.

  • Worth knowing

    FODMAPs and IBS

    Kidney beans are among the highest-FODMAP pulses and a common cause of bloating and pain in irritable bowel syndrome. Rinsing canned beans and using small portions is the usual approach.

  • Worth knowing

    Lectin-free eating is not evidence-based

    Popular books recommend avoiding all lectin-containing foods. The genuine hazard is specific and preparation-dependent: raw or undercooked beans. Properly cooked beans carry no meaningful lectin activity, and the broader elimination diet has no supporting human evidence.

  • Worth knowing

    Phytate and mineral absorption

    Kidney bean phytate reduces absorption of iron and zinc from the meal; vitamin C alongside improves non-heme iron uptake.