When we talk about legumes, we mean those plants that produce a pod with seeds (beans) inside. Technically speaking, legumes are part of the Fabaceae or Leguminosae family. This family contains around 20,000 species. We only know and use a few: beans (white, red, variegated, mung), peas, chickpeas, soybeans, lentils (red, brown, yellow, green) and peanuts.
Legumes are important in the diet, they have a day set as “World Legume Day”, February 10, and it even had a whole year just for them. The Food and Agriculture Organization (FAO) of the United Nations declared 2016 the International Year of Pulses, focusing on the contribution of pulses to food production and nutritional diversity to help eradicate hunger and malnutrition.
As with dairy, legumes have ardent supporters but equally determined detractors. Vegetarians strongly argue that legumes can successfully replace meat, eggs, and dairy, and Paleo followers claim that legumes are pro-inflammatory and toxic. In this article I will try to be objective and shed some light on the controversial topic: legumes.
Nutrients and anti-nutrients
Legumes are the second largest source of protein after animal products. In addition to protein, legumes contain slightly fewer calories than meat, as well as fiber, which meat does not have at all. The disadvantage would be, compared to meat, starch. The disadvantage of meat compared to legumes is the higher content of fat and cholesterol.
Phytic acid
Like grains, pseudocereals, seeds and nuts, legumes contain phytic acid (or phytates). Phytic acid binds to nutrients in food preventing their absorption. It does not bind to nutrients already present in the body, but only to those ingested with food containing phytic acid. If it is cooked properly, as we will see below, much of the phytates are removed. I’ve written about phytic acid here.
Lectins
Lectins are proteins found in almost all types of food, but not all lectins are problematic. These substances can bind to carbohydrates, red blood cells and the cells of the intestinal mucosa. They reduce the absorption of nutrients and hinder the regeneration of the mucosa. Different people react to different lectins, which is why, for example, some people are fine with eating nightshades and others react negatively to them. Potentially toxic lectins are most abundant in grains, legumes and dairy. In the body, lectins damage the intestinal walls, contributing to leaky gut syndrome with all its associated digestive and autoimmune problems.
FODMAPs
Legumes contain a type of carbohydrate called galacto-oligosaccharides that can cause unpleasant digestive problems for some people, especially people who have IBS or similar digestive problems. I wrote about the Low FODMAP diet in this article. FODMAPs cause gas and bloating, effects that many legume eaters are familiar with.
Most people with autoimmune diseases have leaky gut, SIBO, or other gut problems. Legumes are problematic for them because of their FODMAP and starch content. Even properly cooked, legumes are difficult for them to digest. That’s why most healing diets eliminate legumes, at least in the elimination phase, focusing on nutrients from animal foods and vegetables. I wrote about healing diets here.
Proper cooking
To get the most out of the nutrients present in legumes and to reduce the negative effects of phytic acid and lectins there are some simple but laborious cooking methods that require time and advance planning.
Soaking
All vegetables should be soaked for 12-24 hours before cooking. Thus, the anti-nutrients are partially annihilated (30-70%). The grains are tricked into giving up the protection provided by phytates and lectins to begin the sprouting process.
Sprouting
To sprout legumes, we don’t need special equipment, but a jar, a gauze, water and patience. Sprouts are tasty and nutritious. You can eat them raw in salads (occasionally), or lightly cooked (if we eat them more often).
Fermentation
Legumes can be made much more digestible and less harmful by fermenting them. Especially in Asian cuisine, fermented legumes are used, especially soy.
Cooking
After soaking, the legumes should be well cooked. Cook for at least 45 minutes, until they become soft, or bake in the oven. For example, chickpeas soaked, baked in the oven and seasoned with salt, chili or aromatic herbs are very tasty and can replace unhealthy snacks like chips and crackers.
Warnings and exceptions
Peanuts
Despite the appearance and the name, they are not nuts, but legumes, because they come from a pod. Like other legumes, peanuts are problematic due to their content of lectins and phytates, but they also bring another problem: aflatoxins.
Aflatoxins are not actually part of the peanut itself. They are produced by a mold that grows on peanuts as well as other crops such as corn. This mold thrives on crops stored in warm, humid places and is so difficult to remove that it has been declared an “unavoidable contaminant”. Some research has linked long-term consumption of aflatoxins to the risk of diseases such as cancer, especially in countries where peanuts are a staple food. Especially for people with mold sensitivities, peanuts are a particularly worrisome type of legume. Lectins in peanuts are difficult to counteract even by cooking them, unlike lectins in other types of legumes. That is why peanuts are to be avoided.
Soy
Soy is loved by the modern food industry because it’s cheap to grow and incredibly easy to flavor and process into just about anything. But in the long run, such a “cheap” crop comes at a high price: the health of the soil in which it grows as well as the health of people and animals fed genetically modified and ultra-processed soy.
In addition to the same lectins and phytic acid as other legumes, soy has a distinct disadvantage: phytoestrogens. Phytoestrogens mimic the action of estrogen in the body. They don’t actually perform any of the vital functions that real estrogen does. The exact mechanisms by which they do this are very complex, but the result is that they tend to cause hormonal problems because they tell your body that it has enough estrogen when it actually doesn’t.
In men this hormonal imbalance can cause the development of typically “feminine” features such as breasts and fat deposits on the hips. In women, it can affect fertility and lead to all kinds of menstrual and other reproductive problems. Most alarmingly, phytoestrogens have been linked to breast cancer and disruption of normal thyroid function.
In addition to hormones, soy also contains trypsin inhibitors, which interfere with protein digestion and increase the body’s need for several important micronutrients, including vitamin B12 and vitamin D. Soy protein powder, used in supplements, is even worse: it is a completely processed artificial substance, and should not be part of anyone’s diet.
Non-GMO, untreated and unprocessed soy, eaten in small amounts, can be beneficial to health. Soy is eaten in Asia, but the soy products eaten as part of traditional Asian meals have not been industrially processed and they are served in a very nutrient-dense diet that also includes lots of organ meats, fish, bone broth and vegetables. There is a big difference between a small amount of fermented tofu in a large bowl of soup and a spoonful of soy protein isolate in a protein shake full of food coloring and sugar or what is sold in our stores as of “soy meat”.
Conclusions
As they say about dairy, legumes are not necessary for human health. They don’t contain nutrients that we can’t get from other foods, often with less trouble. To preserve nutrients and enjoy them, proper cooking of legumes involves advance planning and extended cooking time.
On the other hand, legumes are cheap, can be stored for a long time and do not require special storage conditions, such as refrigeration and freezing.
Soaking, sprouting, fermenting, boiling and baking removes 30-70% of the toxins from legumes, except for peanuts and soybeans, which have other health risks.
People with autoimmune diseases should be careful about consuming legumes. Do not consume them daily and in large quantities. They have to carefully test if and how much they can consume, and in what combinations with other foods. They can best see what they can tolerate after going on an elimination diet. During the reintroduction period, the tolerability of the initially excluded foods is tested. Carefully and patiently follow the steps for reintroductions, and if something causes them discomfort, it should remain excluded.
