Beans, peas and lentils belong to the legume family. This family is very broad, including around 13000 different varieties. In nature these plants are very important, as they are nitrogen fixers and release nitrogen into the soil for other plants to utilize. In our diets they are very important too, being a great source of protein, fiber and complex carbohydrates.
You get 2 main categories of beans, “immature” or “fresh” and “mature” or dried. Nearly all of the legumes provide a range of nutrients including B vitamins, iron, zinc, magnesium and potassium, but even more so in the mature or dried legumes.
If you are wanting to lose weight, legumes are a highly satiating food, meaning that for a relatively low amount of calories they keep you feeling full for longer, so it may help to avoid unhealthy snacking. Their high fiber content also promotes bowel regularity.
Legumes are sometimes called “poor people’s meat” because they are a relatively inexpensive source of quality plant protein. The only problem is that they need to be combined with whole grains to form a complete protein (neither contains all nine essential amino acids by themselves except for soy).
Possible health issues
Beans may not, however be good for everybody, especially in large amounts or too often. Although they are nutritious, there may be an adverse effect on our health if we consume beans and other legumes on a daily basis, or as a major part of our diets.
Like other grains and pseudograins, legumes contain something called phytic acid. This binds to nutrients in the food, and prevents us from absorbing some of the nutrients in it. Legumes are also FODMAPS, meaning that they contain galaco-ligosaccharides. These specific carbohydrates can cause digestive problems in some people, especially those with IBS or other digestive troubles, and are also found in onions and mushrooms, amongst other foods.
Another aspect to consider is a legume’s lectin content. Lectins are proteins that are found in almost all types of food, but not all lectins are problematic. Not all people react to the same lectins, such as those found in the nightshade family, but potentially toxic lectins are highest in grains, legumes and dairy. Lectins damage the intestinal wall, contributing to a “leaky gut” picture with its associated digestive and autoimmune problems. These lectins can be destroyed by soaking, sprouting and fermenting, but these practices are seldom used anymore.
Green beans are a little different. Most of the problematic elements that have been discussed above are found in the seed of the legume, so green beans have much less phytic acid, for example, than a serving of soybeans. The trick to adding legumes to our diet is in moderation and using the correct preparation techniques.