Red kidney beans

red kidney beans

Most of the carbohydrate in raw red kidney beans is starch, which your body breaks down to glucose. 100 g ends up as about 39.3 g of glucose and about 1.2 g of fructose.

UK CoFID 2021 13-109: Beans, red kidney, dried, raw [source]

red kidney beans (boiled)

Most of the carbohydrate in boiled red kidney beans is starch, which your body breaks down to glucose. 100 g ends up as about 14.7 g of glucose and about 0.4 g of fructose, plus traces of glucose and fructose.

UK CoFID 2021 13-659: Beans, red kidney, dried, boiled in unsalted water [source]

Phytohemagglutinin (PHA, lectin)

As the source gives it

80000–100000 HAU/g (hemagglutinating units), raw dry beans [source]

Dose

raw: 80000–100000 HAU/g (hemagglutinating units), raw dry beans; not in totals: the unit (HAU/g (hemagglutinating units)) is not an amount per 100 gboiled: not in totals: properly boiled beans are a different food from raw ones; the source gives no range for them400 HAU/g base level when properly cooked; 3,200–102,400 HAU/g in beans that caused poisoning (Rodhouse et al. 1990, Epidemiol Infect 105:485–491 (50 UK incidents)). [source]

Cooking

Soak at least 5 h, discard the water, then boil vigorously in fresh water for at least 10 min. Heating to ~80°C does NOT destroy it (slow cookers are a known cause). Tinned beans are already safe. [source]

Threshold

MOE not computable: units differ [source]The source's amounts are in HAU/g (hemagglutinating units); the reference point (no guidance value) is 22.9 mg PHA/kg body weight/day (BMDL10, rat small intestine) (EFSA CONTAM Panel 2026, EFSA Journal 24(1):e9850, no concern above an MOE of 100). EFSA CONTAM Panel 2026, EFSA Journal 24(1):e9850: "exposure to completely deactivated lectins in food prepared following adequate food processing practices (e.g. soaking and boiling) would not raise health concerns"

Effect

As few as 4–5 raw beans cause severe vomiting within 1–3 hours, then diarrhoea; recovery is usually quick. Human observational study

Phytate (phytic acid)

As the source gives it

1201.08 mg/100 g, DRY matter [source]

Dose

raw: 1060 mg in 100 g (converted from dry weight using USDA water content (11.75 g per 100 g, FDC 173744))boiled: 396 mg in 100 g (measured on boiled beans; converted from dry weight using USDA water content (66.94 g per 100 g, FDC 175194))

Cooking

Soaking and boiling did NOT reduce phytate in kidney beans; germination cut it 43%. [source]

Threshold

No established threshold [source]No ADI. EFSA instead raises zinc requirements with phytate intake: at 300/600/900/1,200 mg phytate/day, men need 9.4/11.7/14.0/16.3 mg zinc and women 7.5/9.3/11.0/12.7 mg

Effect

Reduces zinc (and iron) absorption. Regulatory assessment

Alpha-amylase inhibitor (phaseolamin)

Dose

raw: not in totals: no amount in the source data (not found); explainer onlyboiled: not in totals: no amount in the source data (not found); explainer only

Cooking

Boiling at 95°C for 1 h cut activity ~90% (review citation). [source]

Threshold

No established threshold

Effect

None sourced. Not graded

Used in / studied for

Sold as a 'carb blocker'. Trials show ~1–2 kg extra weight loss; one meta-analysis found no significant effect, and the trials are low quality and partly industry-funded.Dose studied: e.g. 2,400 mg extract/dayIn a portion: not comparable: cooking inactivates most of itHuman trial [source]

Condensed tannins

As the source gives it

81 mg catechin equivalents/100 g, DRY matter [source]

Dose

raw: 71.5 mg catechin equivalents in 100 g (converted from dry weight using USDA water content (11.75 g per 100 g, FDC 173744))boiled: not in totals: not measurable after boiling (Godrich et al. 2023)

Threshold

No established threshold

Effect

No human effect data sourced. Not graded