Nutritional values of legumes
Legumes include beans (white, red, mung, azuki, black), lentils (red, black, green), chickpeas, broad beans, peas, soya, and their products.
Fun fact: Peanuts, also known as groundnuts, are formally classified as legumes too. Due to their high fat content, however, in nutrition they are more often classified as nuts.
Legumes have been known for generations, they are cheap and easily available, yet paradoxically… many people forget about their valuable properties. Legumes can easily be given superfood status. Unfortunately, they are often overshadowed by trendy foreign and exotic foods. And that is a pity, because they are a real treasure trove of valuable nutrients.
Legumes are relatively low in calories (110–170 kcal per 100 g of cooked product), yet filling and high in protein. Soya provides the most protein of all legumes, but in fact all of them contain a substantial amount of protein, making up about 25% of their dry weight.
Although legumes are rich in carbohydrates, these are mostly complex carbohydrates that do not cause a rapid spike in glucose. A large part of them is also valuable fibre (about 3–8 g per 100 g of legumes).
Most legumes contain very little fat. The exception is soya, which contains about 20% fat (in dry seeds), mainly valuable fatty acids: oleic and linoleic.
However, legumes are more than just a balanced macronutrient ratio. They also contain a substantial dose of B vitamins, as well as minerals essential for the body’s functioning: iron, calcium, zinc, potassium, and magnesium. Legumes are also rich in antioxidant and anti-inflammatory compounds such as isoflavones, phenolic acids, and plant sterols.
Why eat legumes? Benefits for active people and beyond
Excellent source of iron
Legume seeds are some of the best plant-based sources of iron. There is as much as 8.9 mg of iron per 100 g in soya, about 6 mg/100 g in lentils and about 4.7 mg/100 g in peas. Iron is a haematopoietic element and its optimal level is crucial for maintaining health and very important for athletes, as it directly affects oxygen transport to the muscles, and therefore endurance and performance. Women of reproductive age are particularly prone to deficiencies of this element, so it is important to include its sources in the diet.
It is worth remembering that iron from legumes is non-haemic, i.e. less well absorbed by the body than iron from meat products (haemic). Iron from plant products is absorbed in about 5% and from animal products in about 20%. However, just a few tricks are enough to boost its absorption from legumes:
• Combining legumes with sources of vitamin C – e.g. peppers, parsley, citrus fruits.
• Soaking, sprouting and fermenting legumes before consumption.
• Avoid drinking tea, coffee, or consuming dairy together with legumes.
Magnesium from legumes – excellent support for athletes
Magnesium is invaluable in terms of heart health, circulatory system and muscle function. For active people it is particularly important because of its role in:
• improving performance,
• improving endurance,
• improving regeneration (e.g. by affecting sleep),
• prevention of muscle spasms,
• maintaining electrolyte balance for optimal hydration.
You will find the most magnesium in soya flour (as much as 300 mg/100 g), soya beans (99 mg/100 g), tofu (53 mg/100 g) and other soya products.
In addition to iron and magnesium, legumes also contain other minerals that are very important for health:
• Zinc – essential for the proper functioning of the immune system, as well as for building skin, hair, nails, and tissue regeneration (e.g. after injuries).
• Potassium – crucial for maintaining the body’s electrolyte balance and ensuring proper, efficient heart function. Present in all legumes.
• Calcium – the building block of bones and teeth, and also a key component for electrolyte balance. Soya and soya products have the highest calcium content of plant products.
Healthy plant sterols
Legumes are a natural source of plant sterols (phytosterols). They have a structure similar to cholesterol and compete with it for absorption in the gut. In this way, legumes can directly help lower levels of “bad” LDL cholesterol and indirectly support cardiovascular health, for example by preventing atherosclerosis.
Scientifically proven fun fact: Consuming about 3 g of phytosterols per day can help reduce LDL cholesterol levels by up to 10%.
A good source of protein (not just for vegans!)
Legumes are a good source of protein with an amino acid profile very similar to the so-called reference protein. However, proteins from legumes contain slightly less methionine and more lysine and tryptophan than the reference protein (with an amino acid profile defined as “ideal”). Therefore, to make even better use of the proteins in legumes, it is worth combining them in meals with cereal products, e.g. wholemeal pasta with sauce and soya granules, chickpea spread with bread, barley soup with chickpeas, and so on. The amino acids from different foods consumed together then complement each other and form complete proteins.
While every type of sports activity is possible on a plant-based diet, there is no need to go fully vegan. You can also benefit from the extra protein in legumes if you follow an “omnivorous diet” and eat meat or dairy. Including legumes in your diet is a great way to sneak extra protein into meals while keeping them healthy. Red bean brownies, hummus on sandwiches instead of butter, lentil pancakes, tofu added to stew, lentils in soup – these are just a few ideas for incorporating legumes into your diet to add extra protein, so valuable for active people when it comes to recovery, building muscle mass, or tissue repair.
Prevention of lifestyle diseases
Research confirms that increasing legume consumption has a positive impact on health and can help prevent many lifestyle diseases, genuinely improving quality of life and extending its duration. Here are some serious and common diseases that can be partly prevented (or supported in treatment) by increasing legume consumption:
• Obesity. Legumes are characterised by a high satiety index. They can help maintain an effective weight-loss diet or prevent overeating and snacking on high-energy foods that contribute to obesity. The extensive NHANES observational study showed that adults who regularly consumed legumes had significantly lower body weight (and lower risk of obesity) than those whose diets included fewer legumes.
• Cardiovascular diseases are the leading cause of death in Polish society, and they develop mainly due to an unhealthy lifestyle, low physical activity, and poor diet. The Mediterranean and DASH diets are the dietary answer to and effective prevention of cardiovascular disease. Both include legumes as part of the diet. Legumes have a positive effect on blood pressure, lipid profile, and also show anti-inflammatory properties.
• Cancers. Dietary cancer prevention takes into account, among other things, reducing red meat consumption in favour of legumes. Legumes have shown anti-cancer properties in many scientific studies.
• Diabetes. Legumes are an excellent part of a diet for preventing diabetes, as well as a valuable component of the diet for diabetics and people with insulin resistance. Thanks to their balanced macronutrient composition, legumes have a low glycaemic load and a high nutrient density in terms of elements important for diabetics: potassium, fibre, and antioxidants.
Scientifically proven fun fact: In the Nurses’ Health Study and the Health Professionals Follow-up Study, involving over 50,000 participants, a significantly lower overall mortality rate was observed in people who regularly consumed plant-based protein (mainly legumes) compared to those who consumed animal-based protein.
Support of the intestinal microbiome
Legumes are an excellent source of dietary fibre. It not only has a positive effect on bowel function but, above all, serves as nourishment for the microbes living in the intestines. The role of the gut microbiome for the whole body is invaluable and is still being explored by scientists, who continue to discover new areas it affects – from immunity and skin condition to brain function.
Legumes as a source of energy
In addition to protein, legumes also provide the body’s main fuel – complex carbohydrates that are released slowly. It is therefore good to include them in a post-workout meal to support recovery, as well as to eat them regularly in main meals, since they are a component of the world’s healthiest diet – the Mediterranean diet.
Important: If your daily diet does not include many legumes, do not experiment with adding them right before important sporting events or competitions. In people who are not used to them and are sensitive to high-FODMAP foods, legumes often cause gut discomfort and bloating. They are also a rich source of fibre, which has many long-term benefits in the diet, but before sports competitions it may put a strain on the digestive system.
Antioxidants from legumes and post-exercise recovery
Legumes are a rich source of polyphenols, peptides, isoflavones, and saponins, which have anti-inflammatory effects. An anti-inflammatory diet is a diet that promotes better immunity and longevity. However, there are also short-term benefits – an extra portion of legumes in a post-workout meal can boost the meal’s antioxidant potential. This is particularly important when speed of recovery is crucial for optimal performance.
Scientifically proven fun fact: Soya isoflavones have a significant effect in reducing the risk of endometrial and breast cancers in women, as well as prostate cancer in men.
How to eat more legumes? Practical guide
Have the above arguments convinced you to add more legumes to your diet? Do it carefully and follow a few rules.
Build tolerance
If legumes have appeared infrequently in your diet so far, introduce them slowly into your menu. Start with a serving of 2 tablespoons of cooked legumes a few times a week, for example as an addition to soups, salads, or as a spread on bread. Slowly increase the frequency of their consumption and the portion.
At the beginning, a fairly mild option such as lentils works well, as they do not require long cooking, have small seeds, and are easy to add to soups, sauces, or stews.
Do not be discouraged after a few attempts
Legumes are a rich source of fibre and fermentable carbohydrates (high FODMAP) and can have a bloating effect. If your body is not used to the presence of legumes and higher doses of fibre in your diet, you may experience various digestive discomforts such as gas, bloating and a feeling of overeating. By building up a tolerance to legumes, you will partially reduce such effects over time, so do not be discouraged after a few attempts.
Of course, there are people for whom building tolerance to legumes will be more difficult, or who will never fully feel comfortable after eating these products. Be patient when expanding your diet to include this ingredient, but also keep in mind that there are conditions such as IBS (irritable bowel syndrome), where achieving full tolerance may not be possible or may be more difficult. If in doubt, seek advice from your doctor and/or clinical nutritionist.
Find tasty ways to make meals with legumes
According to one study on legumes in the diet, the main concerns about increasing legume consumption are lack of culinary knowledge, the belief that they require long preparation, fear of digestive problems, and the so-called taste barrier. Meanwhile, there are plenty of tasty ways to include legumes in your diet.
Feel free to use legumes in their pure form, but do not shy away from products that enhance their culinary versatility. Try: soya cutlets, soya granules (an excellent alternative to minced meat), tempeh, tofu, silken tofu, and various spreads for bread. Pasta made from legume flour, such as lentils, peas, or chickpeas, is also an excellent product. They are becoming increasingly available and have the added advantage of cooking faster than regular pasta.
Do not overdo it
“Too much of a good thing is not healthy,” and with legumes you may find this out the hard way if you overdo a single portion and are sensitive to high-FODMAP foods. The health benefits of legumes will be greater if you eat them regularly in different meals, rather than in large single portions.
Prepare the legumes in the right way
Here are some culinary patents to improve the digestibility of legumes:
• Soak legume seeds before cooking (for 8–16 hours in cold water, or about 4 hours in boiling water). It is worth doing this because of the cooking time. Soaking significantly reduces the cooking time of legumes by activating the naturally occurring enzymes in their skins beforehand. It is also a good idea to use some soda to soak legumes.
• To reduce the bloating properties of legumes, it is worth discarding the soaking water before cooking the seeds.
• Canned legumes can be more convenient than cooking them yourself, and they are also a good choice for health. To reduce their bloating properties, drain the legumes from the can and rinse them thoroughly under running water.
• It is worth consuming legumes with spices and substances that reduce their bloating properties, such as caraway, thyme, or rosemary. They will then also gain extra flavour.
References:
- Commission Regulation (EU) of 20 June 2014 amending Regulations (EC) No 983/2009 and (EU) No 384/2010 as regards the conditions of use of certain health claims related to the effects of plant sterols and plant stanols on the lowering of blood LDL cholesterol (2014/ 686/EC).
- Polak R., Phillips E. M., Campbell A., Legumes: Health Benefits and Culinary Approaches to Increase Intake, Clin Diabetes. 2015 Oct;33(4):198-205, doi: 10.2337/diaclin.33.4.198, PMID: 26487796; PMCID: PMC4608274.
- Hughes J., Pearson E., Grafenauer S., Legumes-A Comprehensive Exploration of Global Food-Based Dietary Guidelines and Consumption, Nutrients. 2022 Jul 27;14(15):3080, doi: 10.3390/nu14153080, PMID: 35956258; PMCID: PMC9370574.
- Winham, Donna M., and Andrea M. Hutchins, Perceptions of flatulence from bean consumption among adults in 3 feeding studies, Nutrition journal 10.1 (2011): 128.
- Juárez-Chairez M. F., Meza-Márquez O. G., Márquez-Flores Y. K., Jiménez-Martínez C., Potential anti-inflammatory effects of legumes: a review, British Journal of Nutrition, 2022;128(11):2158-2169, doi:10.1017/S0007114522000137
- National Centre for Nutrition Education, Legumes are healthy! Practical dietary guide on how to reduce meat in the diet in favour of plant-based products, B. Bondyra-Wiśniewska et al, Warsaw, 2021.