Natural Toxins in Raw/Undercooked Beans (2024)

FAQs

Natural Toxins in Raw/Undercooked Beans? ›

Lectins. Many types of beans contain toxins called lectins, and kidney beans have the highest concentrations – especially red kidney beans. As few as 4 or 5 raw beans can cause severe stomachache, vomiting and diarrhoea.

Consumption of common beans (e.g. green beans, French beans) and other beans (e.g. red kidney beans, white kidney beans) without proper processing may cause poisoning due to the naturally present toxins lectins (e.g. phytohaemagglutinins). Acute poisoning symptoms may include vomiting, diarrhoea, and abdominal pain.

The FDA's “Bad Bug Book” explains that the lectin phytohaemagglutinin has toxic effects in human when consumed in high levels. Red kidney beans have the highest levels of it. The unit to measure the toxins is called hemagglutinating unit (hau).

The haemagglutinin (lectin), which occurs naturally in the red kidney bean, is inactivated by thorough cooking of well soaked beans. In many of the outbreaks reported the implicated beans were consumed raw or following an inadequate heat process.

Lectins are found in all plants, including legumes, but dried red kidney beans and cannellini beans are the only ones that contain a high enough concentration of PHA to temporarily sicken humans. The good news? Eliminating the toxic level of lectin in the beans is super easy.

Lectins. Many types of beans contain toxins called lectins, and kidney beans have the highest concentrations – especially red kidney beans. As few as 4 or 5 raw beans can cause severe stomachache, vomiting and diarrhoea.

This can lead to stomach upset like nausea, vomiting, diarrhea and bloating. Consuming a large amount of lectin could even damage the good bacteria in your gut. Biting into one raw green bean likely won't cause any issues. You'd have to eat a large amount to start feeling the digestive problems from lectin.

But that's not all; white, broad, black, pinto, great Northern, and navy beans are all on the list of foods you should never eat raw. Lima beans are also toxic when eaten raw but not because of lectins; they contain a chemical called linamarin that breaks down into cyanide when digested.

Eating raw or undercooked kidney beans can lead to food poisoning, including symptoms such as nausea, vomiting and diarrhea. Only a few beans are needed to cause poisoning. Kidney beans, or red beans, contain a natural protein, Lectin, that is found in many plants, animals and humans.

Control of phosphorus often is difficult for kidney failure patients. High-phosphorus foods to eliminate include: Beans (red, black, and white) Black-eyed peas.

How long to boil beans to remove toxins? ›

Raw kidney beans contain the toxin phytohemagglutinin and must be boiled for 10 minutes to destroy it. Phytohemagglutinin is not lethal by any means, but may cause gastrointestinal discomfort and symptoms similar to food poisoning. Always boil kidney beans for 10 minutes, then reduce the heat and simmer until cooked.

Consuming green beans in their raw form may offer a unique benefit compared with cooking them first: They retain more of their natural nutrients and antioxidants this way. Cooking them may diminish some of the vitamins available in green beans, including folate and vitamin C.

In some people, beans may cause unpleasant effects, such as bloating, flatulence, and diarrhea ( 13 ). Insoluble fibers called alpha-galactosides are responsible for these effects. They belong to a group of fibers known as FODMAPs, which may exacerbate the symptoms of irritable bowel syndrome (IBS) ( 7 , 59 , 60 ).

All uncooked beans contain toxins that can make you very sick. In fact, about 20% of all cases of severe food poisoning are attributed to the consuming of undercooked beans. Always make sure that beans are thoroughly cooked and soft all the way through before eating them, or use canned beans.

Boiling beans

The good news is that the toxin can be deactivated by simply boiling the raw beans for ten minutes. This temperature degrades the toxin without cooking the beans. The FDA also recommends soaking the beans for five hours to remove any residual toxins and then tossing the water out.

The dangers of raw beans

Eating just four raw, soaked beans is enough to cause symptoms of foodborne illness. Crockpots are popular methods for cooking raw beans, but this method can yield dangerous results.

Castor beans, for example, contain a potent lectin poison called ricin. Damage to the Digestive System. Certain types of lectin may bind with the walls of your digestive system which can lead to serious problems. Eating one particular lectin, phytohemagglutinin, can lead to severe abdominal pain, vomiting, and diarrhea ...

Beans contain more soluble fiber than any other food category in the plant kingdom, which is why this food takes center stage. Basically, what's happening in the body is: soluble fiber binds to toxin-carrying bile and escorts it out of the body, allowing for new, healthy bile to start flowing.

Cooking your beans until they are super soft will help to decrease gas as this removes the oligosaccharides, or starts to break them down, so less undigested pieces will reach the gut bacteria.