Legumes, specifically beans, are a common food staple across many cuisines. They are popular not only because of their health benefits — rich in fiber and protein, low in fat, cholesterol free, and packed with vitamins and minerals — but also because they are a versatile ingredient used in countless favorite recipes.
But if you're not careful, there are some serious dangers to eating undercooked legumes. Legumes are plants in the Fabaceae family; any part of the plant, including seeds, pods, stems, and leaves, are considered legumes. It is a category that encompasses beans and pulses. Pulses are the seeds of legumes and can include many beans but also peas and lentils. All beans and pulses are legumes, but not all legumes are beans or pulses. Peanuts are legumes but not pulses, for example.
The Dangers of Eating Undercooked Beans
When it comes to eating legumes, one of the major things to watch out for is the presence of glycoproteins called lectins, an "anti-nutrient." Glycoproteins are super common in many plants we regularly eat, but some lectins are harmful because they bind in the digestive tract and coagulate red blood cells leading to a host of gastrointestinal issues like nausea, cramping, vomiting, and diarrhea, among others. The most toxic of all lectins are found in pulses like lentils or chickpeas. Symptoms usually start just a few hours after ingestion and can last four hours or more in extreme cases. Eating just four raw beans is enough to bring on these symptoms. The good news is that lectins are easy to get rid of; all you have to do is cook them. When heated past 212 degrees F (100 degrees C) for 30 minutes or more, the lectins are destroyed.
Recently, there's been a lot of talk in the news about lentils. They contain much less lectin than other legumes, but they can still cause serious gastrointestinal distress. With the recall of Daily Harvest's lentil crumbles, many people are more aware of proper legume cookery now more than ever. And while it's always essential to thoroughly cook lentils, it looks like they weren't the culprit in the Daily Harvest recall. If you're unfamiliar, Daily Harvest, a ready-made health food delivery service, recently recalled their vegan lentil-based "crumbles" after about 470 reports of illness. Customers who ate them experienced severe gastrointestinal distress, resulting in hospitalization, and some even had to have their gallbladders removed. It looks like the real culprit was a vegan protein source called Tara flour. It comes from the seeds of the Tara tree, a legume. Generally, byproducts of the Tara tree aren't something that causes such severe reactions, so it's assumed that the issue was in the way the flour was processed and manufactured.
How to Cook Beans Safely
Cooking dried, raw beans can be a cheap and delicious alternative to precooked canned beans. When you start with raw, there are a few important things to remember. The basic guidelines for ensuring properly cooked beans are simple.
First, it's always best to soak your beans; about 5 hours should do the trick. There are a thousand articles online about how to skip this step, but in terms of food safety, it's an important one. During that time, the water has a chance to leech out some of the lectins. So always make sure to change your water before tossing them in the pot and then boil them for at least 30 minutes.
And though it might be tempting, you should avoid cooking beans in the slow cooker because on their lowest settings; most don't get hot enough to destroy the lectins. A quick trick to test your beans for doneness is to scoop up a spoonful and blow on them. If the skins curl and peel back from the bean's interior, they're just about done.
Which Legumes Can You Eat Raw?
Most beans and legumes need to be fully cooked to be safe, but a few can safely be enjoyed raw. Many seeds fall into this category as well. Flax, chia, pumpkin, sunflower, hemp, and sesame seeds are all safe (and delicious!) to eat raw.
Peas are a popular legume that are perfect to enjoy, raw or cooked, when fresh. Sweet green shelling peas are bountiful in the spring and delicious eaten right out of the pod. Similarly, fava beans are a great bean to eat raw. When they're very young, they can even be eaten pod and all.
Mung beans aren't the flashiest legume, but they contain zero lectins and are packed with nutrition. They're great raw but are even better sprouted. Sprouting involves soaking many types of beans or legumes until they begin to sprout. The amount of time depends on the specific legume, but it usually can be achieved in a day or two. Some beans like chickpeas and soybeans are indigestible when raw but are safe and delicious when sprouted.
Which Should You Never Eat Raw?
Most beans and many other legumes are unsafe to eat raw, if you're not sure, it's a much safer choice to just cook them through. Red kidney beans top this list with the highest levels of toxic compounds. 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.
