Hyacinth Beans (Lablab): Nutrients, What Research Shows and Safety

Hyacinth beans, also called lablab or dolichos bean, are the seeds and pods of Lablab purpureus (family Fabaceae, the legume family). People in parts of Africa, Asia and the Caribbean eat the young pods, the immature seeds and, after long cooking, the dry seeds. [3] [5] This page covers the bean as food. Safety comes first, because the mature seeds are one of the legumes that must be prepared with care. It also keeps hype and lab findings apart from what people have been tested on.

Read this first

• Do not eat the mature dry seeds raw or lightly cooked. NC State Extension lists the seeds as a low-severity poison for people because of a cyanogenic glycoside (a natural plant chemical that can release cyanide), and says it is a problem only if large amounts are eaten. For mature dried seeds it lists weakness, vomiting, labored breathing, twitching, stupor and convulsions. [3]
• How the sources say to prepare them: NC State says mature dried seeds are edible if thoroughly boiled, changing the water several times. [3] PROTA, a reference work on African plants, says dry seeds are eaten as a pulse in northern Nigeria and Kenya after prolonged cooking with several changes of water. [5] Neither gives a number of minutes, and we found no official food-safety body (such as the FDA or Health Canada) with a time for this bean.
• Do not copy the kidney-bean times. The FDA (soak at least 5 hours, boil at least 30 minutes) and Health Canada (at least 10 minutes of vigorous boiling) give those times for red kidney beans, a different bean and a different toxin. [6] [8] We found no source that says they are enough for hyacinth beans.
• Young pods and immature seeds are the usual vegetable. NC State says young immature pods can be cooked and eaten. [3] [5]
• Evidence in one line: we found no trial of hyacinth beans in people. Pooled trials of pulses as a group show a small fall in LDL cholesterol. [15]
• Allergy and kidney notes: bean allergy is possible (for trouble breathing or swelling of the face or throat call 911 or your local emergency number). [14] People with a history of calcium oxalate kidney stones are told to ask about the oxalates in beans. [12]

What is in it (USDA values)

The main columns are for hyacinth beans, mature seeds, boiled without salt (USDA FoodData Central item 175211, SR Legacy). [1] The serving is the USDA household portion of 1 cup, 194 g. [1] The last column is the same bean raw and dry (item 175210) per 100 g. [2] Do not compare the raw and cooked columns directly: cooked beans are about 69% water and the dry beans about 9%. [1] [2]

% Daily Value uses the FDA 2016 Daily Values and is our calculation from the USDA per-100-g figure times the USDA gram weight; values vary with variety, growing place and cooking time. [1] USDA lists no fiber value for the cooked item (the raw item lists 25.6 g per 100 g, a dry-weight figure), and where a row is missing USDA has no value. [1] [2] We did not read USDA values for canned or frozen hyacinth beans or for fresh pods.

Plant compounds: the sources we read name these in the bean: cyanogenic glycosides, trypsin inhibitors, haemagglutinins (lectins), tannins and phytate (all in the dry seed, no amounts given) [5], and tannins and saponins detected, not measured, in green pods of six Bangladeshi cultivars. [9] Recent reviews call the bean rich in phenolics (plant chemicals with antioxidant effects in the lab); their abstracts report antioxidant, antidiabetic and other activities but no human trials, and we did not read the full reviews. [10] [11]

What research says

Eaten as food vs taken as extract or supplement. The pulse trials above fed ordinary cooked pulses. We read no trial of hyacinth bean extracts or supplements, and the lab findings in the reviews concern extracts, so do not assume they apply to a bowl of cooked beans. The reviews' abstracts do not state funders, so we cannot say who paid. [10] [11]

How much is a normal serving

The USDA household portion is 1 cup of cooked beans (194 g), about 227 kcal. [1] In the pooled LDL analysis, the trials used a median of about 130 g of pulses a day. [15] These are descriptions of what USDA and the trials used, not a prescription or a target for you. This is information, not advice.

Safety, allergy and medicines

• Natural cyanide compounds in mature seeds: see "Read this first". PROTA says the dry seeds have a high content of toxic cyanogenic glucosides, that heat breaks them down, and that dry seeds need prolonged cooking with several changes of water where they are eaten as a pulse. [5] Cornell says cooking breaks the compounds down. [4] Because the sources give no times, we do not give any.
• Lectins and other raw-bean compounds: PROTA lists haemagglutinins (lectins), trypsin inhibitors, tannins and phytate in the seed. [5] The FDA says the lectin PHA in raw or undercooked red kidney beans can cause nausea, severe vomiting and diarrhea. [6] Harvard says raw legumes in general contain some of the highest lectin levels, that wet high heat such as boiling inactivates most of them, and that simmering raw beans at low heat, as in a slow cooker, will not remove all lectins. [7] So do not cook dry hyacinth beans only in a slow cooker.
• Gas and digestion: beans can cause extra gas. [13]
• Kidney disease: the National Kidney Foundation says the potassium and phosphorus in beans are absorbed less well than from animal foods or additives, and that most people with chronic kidney disease not on dialysis do not need to limit beans for those minerals; people on dialysis should plan beans with a kidney dietitian. It also advises people with a history of calcium oxalate stones to ask about oxalates, since many beans are high in them. [12] We did not read an oxalate value for hyacinth beans.
• Allergy: MedlinePlus lists peanut and soy among the major food allergens and describes hives, swelling, vomiting, wheezing and anaphylaxis, a medical emergency (call 911). [14] We found no source on allergy to hyacinth beans specifically, so we cannot say how common it is or whether it cross-reacts with peanut or soy. Peanut is a legume (see peanuts).
• Pregnancy, breastfeeding and children: we did not find official guidance on hyacinth beans. See what official bodies advise in pregnancy.
• Medicines: we did not find a source we could read describing a direct interaction between cooked hyacinth beans and a medicine. See foods and medicine interactions.

Choosing, storing and food safety

• Treat dry hyacinth beans as a bean that needs long, thorough boiling in plenty of water with the water changed, as the extension and reference sources say. [3] [5]
• Young green pods and immature seeds are eaten cooked as a vegetable. [3] [5]
• We read no official source on storing dried hyacinth beans. For leftovers, see food storage, leftovers and food safety basics.

Related pages

• Lima beans
• Lectins in beans: cooking dried beans safely
• Soaking and cooking times for dried beans and lentils
• Beans, gas, FODMAPs and digestion
• Foods and kidney disease: potassium and oxalates
• Food allergy basics and emergency signs