You can eat green beans raw, but weighing the pros and cons it’s probably better to cook them. If you enjoy eating raw green beans you are safe to keep doing so. If you’ve never eaten raw green beans and want to then go for it. You may experience indigestion or in very rare cases diarrhea and/or vomitting. Canned beans are pre-cooked and can be eaten directly out of the can without worry.
Green beans contain lectins that can cause indigestion in some people. The very worst case scenario if you are highly sensitive to lectins is diarrhea and vomitting. Most green beans have a low lectin amount compared to other legumes and eating raw green beans is very unlikely to result in a severe reaction.
When you cook green beans there will be some loss of nutrients but that is outweighed through better absorption of the minerals that are present. Also there’s a very small chance of having an upset stomach in people that are sensitive to lectins when cooked.
Are Green Beans Poisonous?
Green beans are mildly toxic. This is not a big deal as most foods contain some toxins and some of those are actually beneficial to us. Caffeine is a toxin that some plants produce. Unfortunately for them it’s a toxin humans love. Green beans are one of the least poisonous beans around. Raw lima beans actually contain cyanide.
Green beans have mild doses of toxins and should be fine to eat raw but probably shouldn’t be made a staple of a raw foods diet. The highest concentration of toxins is located in the seeds and not the pods so if you are picking raw beans for a salad look for young beans with small seeds.
Try Them Out
You may have heard of people going on a gluten free diet because of a gut problem like leaky gut syndrome or Chron’s disease. Some times people eliminate all foods with lectins while trying to improve these problems or other autoimmune diseases. If you have regular gut or digestion troubles lectins may be a source of gut problems for you.
A way to tell if lectins are the source of your digestive troubles is an elimination diet. This is done by eating a very plain diet without any of the foods that you think you may be sensitive to. Then foods are gradually introduced back into the diet and in this way you can tell what foods cause you problems.
Another option is to take a food sensitivity test. This is supposed to tell you what foods causes the most distress to your system. The accuracy of these tests is questionable with test results varying largely from day to day.
Because of people’s different sensitivity levels to phytic acids and lectins and the wide range of lectins that can be present in different varieties of green beans the best way to know if raw green beans bother you is to try them out.
The Science Behind It
Green beans contain phytic acid and a protein called lectin. Both lectin and phytic acid are anti-nutrients. Anti-nutrients are plant or synthetic compounds that reduce the bodies absorption of minerals. Phytic acid binds with minerals like zinc, calcium, magnesium, and iron and prevents absorption. They exit the body with no benefit to us.
Lectins provide a natural defense for plants to any animal or insect that would otherwise enjoy eating them. In fact, lectins have been successfully introduced into the genes of wheat, rice, potatoes, and tobacco plants for the purpose of repelling insects.
Lectins do not dissolve in digestive enzymes and bind to the surface of cells in the gut. For humans, lectins can do damage to intestinal cell walls and good gut bacteria. The body reacts to this outside threat by emptying the intestines completely through diarrhea and/or vomiting. Other symptoms include nausea, bloating, and gas.
The most famous of lectins is gluten. The lectin found in green beans and legumes is phytohaemagglutinin (PHA). Most of the PHA is removed after cooking. Raw kidney beans for example, have anywhere from 20,000 to 70,000 HAU’s (hemagglutinating units) raw and around 200-400 after being fully cooked.
The amount of lectins is not nearly as high in green beans as it is in other beans like kidney beans and lima beans. Eating undercooked beans that are high in lectins can result in food poisoning. Usually a severe reaction will include diarrhea and vomiting but the symptoms will subside in a few hours. A trip to the hospital may be advisable with severe symptoms and an IV with fluids can aid recovery time.
Kidney beans and lima beans need to be soaked for at least a few hours and then drained and boiled in fresh water. The soaking time combined with 10 minutes of cooking in boiling water should be sufficient to hugely reduce the lectin content.
Most of the lectins are found in the seed of the green bean rather than the pods. Here’s a scientific study that shows in table 3 the amount of lectins found in 7 different cultivars of green beans. The ranges of lectin that are in a green bean seed can vary drastically from 5-1,100 mg per 100 grams. Most varieties included are around the 100 mg per 100 grams of seeds. Phytic acid measures around .15 grams in uncooked green beans and .05 grams in cooked green beans. To further complicate things some people are sensitive to lectins and phytic acid and some aren’t.
Better to Cook Green Beans or Eat Them Raw?
Canned beans are pre-cooked and can be eaten directly out of the can without worrying about lectins. Frozen green beans will lose vitamins if thawed before cooking so take them straight from the freezer onto the stove.
Cooking green beans causes around a 30% drop in vitamin C, potassium, iron, and magnesium but will have the same levels of B-vitamins and vitamins A and E as eating raw green beans. Nutrient absorption is also diminished when green beans are eaten raw because of lectins and phytic acids present in the raw form acting as anti-nutrients.
There is a study that shows that anti-oxidant levels increase when green beans are cooked. Anti-oxidants take out free radicals that can cause havoc on healthy cells. Another study shows that cooking green beans increases carotenoids β-carotene, lutein and zeaxanthin. Carotenoids are fat soluble vitamins that have been shown to have cancer reducing properties. They are also responsible for the pink color of flamingos.
Because cooking green beans gets rid of lectins that are responsible for indigestability and discomfort in some people it makes sense to cook green beans. Eating green beans raw may give a slight nutritional content increase but this edge in nutritional content may be awash because of the indigestibility of the raw form green bean. Also green beans cooked have been shown to have increased anti-oxidants and carotenoids.