What is a legume?

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why might farmers plant legumes such as peas to improve the nitrogen levels in their soil

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Discovery in legumes could reduce fertilizer use, aid environment, say Stanford researchers

Stanford Report, February 26, 2010

Escalating use of nitrogen fertilizer is increasing algal blooms and global warming, but a discovery by Stanford researchers could begin to reverse that. They have revealed a key step in how symbiotic bacteria living in legumes turn nitrogen into plant food, which could be used to improve the process in some plants, reducing the need for chemical fertilizers.

By Louis Bergeron

Courtesy of Sharon Long

Bacteria (left) and the root nodules (right) in which they reside as they fix nitrogen inside barrel matic, a leguminous forage crop similar to fellow legume alfalfa, shown in the field in the background.

Nitrogen is vital for all plant life, but increasingly the planet is paying a heavy price for the escalating use of nitrogen fertilizer.

Excess nitrogen from fertilizer runoff into rivers and lakes causes algal blooms that create oxygen-depleted dead zones, such as the 6,000 to 7,000 square mile zone in the Gulf of Mexico, and nitrogen in the form of nitrous oxide is a potent greenhouse gas.

But new findings by Stanford researchers that reveal the inner workings of nitrogen-producing bacteria living inside legumes such as soybeans could enable researchers to blunt those negative effects and aid efforts to make agriculture more sustainable.

“We have discovered a new biological process, by which leguminous plants control behavior of symbiotic bacteria,” said molecular biologist Sharon Long. “These plants have a specialized protein processing system that generates specific protein signals. These were hitherto unknown, but it turns out they are critical to cause nitrogen fixation.”

The ability of legumes to capture nitrogen from the air and turn it into plant food, or “fix” it, also leaves the soil enriched through the plant matter left after harvesting, creating a natural fertilizer for other crops, which is the basis for crop rotation. Alternating legumes with other crops has been a major component of agriculture around the world for thousands of years. Yet until recently, little was known about how nitrogen fixation worked, or why some legumes are efficient at fixing nitrogen and others poor.

The key part of the process that Long’s research group uncovered is a plant gene that triggers a critical chemical signal. Without the signal, no nitrogen gets fixed by the bacteria. Dong Wang, a postdoctoral scholar in Long’s lab who pinned down the gene, is first author of a paper describing the work, published Feb. 26 in Science. Long, a professor of biology, is senior author.

Do-it-yourself nitrogen fixing

The beneficial bacteria in question reside inside the nodules of legumes such as peas, beans, alfalfa and clover, where they pluck molecules of nitrogen from air in the soil and turn it into ammonia, which feeds the plant. It sounds simple, but it is a complicated and poorly understood process. Only bacteria that contain a special enzyme are capable of this sort of “nitrogen fixing” using airborne nitrogen – no other type of living organism can do it. All other plants have to get their nutrients from using already fixed nitrogen in the soil.

L. A. Cicero

Stanford molecular biologist Sharon Long’s discovery could reduce the need for harmful chemical fertilizers.

This special ability allows legumes to flourish in nitrogen-poor soils, whereas other plants require applications of manufactured nitrogen fertilizer to grow well. But even legumes can’t flourish without the right symbiotic bacteria.

“When you deal with a natural soil, you are dealing with a lot of complexity. Everything we learn about what makes symbiosis work gives us a tool to understand why, sometimes, symbiosis fails,” Long said. “Plant breeders who are trying to help develop better-adapted plants can now analyze traits such as this. We’ve given them a new tool.”

The more efficient that legumes can be made and the wider the range of environments they can thrive in, the more they can help reduce the need for chemical nitrogen that runs off into water or sinks into the groundwater or decomposes into a gaseous form, Long said.

The gene’s the thing

The legume that Long’s team worked with is called barrel medic, a forage plant similar to alfalfa. They tracked down the newly discovered gene by studying mutant plants that were failing to produce healthy nodules on their roots.

While bacteria inside normal nodules will thrive, in the defective nodules of this plant those bacteria can’t provide the benefit they are wired to deliver. Long said that the mutant “contained perfectly good bacteria, but was making these lousy nodules.”

Wang found that the mutant plants generated the proper precursor to the protein needed to nudge the bacteria into fixing nitrogen. But the critical enzyme for processing that precursor into the final signal was missing. So the bacteria simply sat, the nodules didn’t develop and no nitrogen got fixed.

By comparing the genome of the mutant plants with normal plants, the group found a gene that was missing from the mutants. Suspecting that gene might be the culprit, the researchers took a functional version of the gene from normal plants and put it into the mutants. The mutant legumes then began fixing nitrogen the same as normal ones, “proving that we found the right gene,” said Wang.

How less is more

Since 1960, the use of nitrogen fertilizer in the United States has roughly quadrupled, as has the price per ton, according to the U.S. Department of Agriculture. Prices have been driven up by the rising cost of natural gas used to manufacture the fertilizer.

“That might make things more expensive for American farmers and increase food prices for consumers, but this is going to wipe out people in developing countries, whose soils are perhaps most in need of fertilizers,” Long said. “This is a crucial issue. And nitrogen fixation is a key to sustainability.”

Costs aside, the production of chemical fertilizer also adds to the problem of global warming, both by way of the fossil fuels used in production of chemical fertilizer and through the impact of leftover fertilizer that degrades into nitrous oxide, a highly potent greenhouse gas.

With the planet’s ever-growing population, Long said there is going to be increased need to keep productivity going on lands that are starting to become marginal because of drought, temperature or salinity problems, among others.

“The rhizobium bacteria are a critical partner in whether that kind of extension of serviceable land can occur,” she said. “In order for us to take existing symbioses and help make them better, optimize them for being productive even when conditions start to deteriorate, tools such as understanding how to improve nitrogen fixing in legumes are crucial.”

Joel Griffitts and Colby Starker, also authors on the paper, contributed to the research when they were graduate students or postdoctoral scholars in Long’s lab. Griffitts is now an assistant professor at Brigham Young University. Starker is a research associate at the University of Minnesota. The research was supported by the Howard Hughes Medical Institute, the Helen Hay Whitney Foundation and the National Science Foundation.

Louis Bergeron, Stanford News Service: (650) 725-1944, [email protected]

How Legumes ‘Fix’ Nitrogen in Your Soil

Legumes (peas, vetches, clovers, beans and others) grow in a symbiotic relationship with soil-dwelling bacteria. The bacteria take gaseous nitrogen from the air in the soil and feed this nitrogen to the legumes; in exchange the plant provides carbohydrates to the bacteria. This is why legume cover crops are said to “fix” or provide a certain amount of nitrogen when they are turned under for the next crop or used for compost.

Rhizobacteria are naturally present in the soil, but their populations are often too low to maximize nitrogen fixation. For the best nitrogen fixation, inoculate or coat the seed with purchased rhizobium. Specific strains of rhizobacteria work with different legumes. Read the packages carefully to ensure that you purchase the correct rhizobacteria for the legume cover crop you have chosen to sow.

To coat the seed, put it in a container and moisten it slightly with water or milk. The liquid will help the inoculant coat the seed. Sprinkle approximately 1 heaping tablespoon of inoculant per ½ pound of seed.

The rhizobia are living organisms, so you should sow the seed as soon as possible after coating it. Do not leave inoculated seed in the sun because the soil-dwelling creatures can’t live in UV light.

All legumes need adequate supplies of phosphorus, calcium and sulfur. Fall is a good time to test the soil for these major nutrients and adjust the soil content by adding lime, rock phosphate or gypsum as needed.

Contact our Garden Hotline for more information or to get custom answers to your specific questions, (206) 633-0224. Get more information on organic gardening topics in Seattle Tilth’s “Maritime NW Garden Guide” or ”Your Farm in the City.” Check out our list of classes.

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ChamilleWhite/iStock/GettyImages

Legumes are plants that have pods with their seeds inside, such as the various types of beans and peas. Soybeans, fava beans, peas and peanuts are all legumes. Legumes offer a number of health benefits to individuals who include them in their diet.

Beans

Legumes are low in fat, and high in potassium, iron and magnesium. They can be a good meat substitute. Beans are high in healthy fats and proteins, which makes them a good addition to any diet regimen. Good beans include black beans, chickpeas or garbanzo beans, edamame, lima beans and soy nuts.

Peas

Peas are rich in proteins and contain healthy carbohydrates. Whole, mature peas are a great addition to any meal. The immature pea pod can also be consumed as snap peas or snow peas. Peas are a good source of nutrition for people and are often fed to livestock as well.

Forage Legumes

Forage legumes, often are planted to prevent erosion, create hay and feed livestock animals, like cows and pigs. These types of legumes are sometimes regarded as weeds, despite their useful nature. Alfalfa, vetch and clovers all are considered to be forage legumes.

Legumes: what are they and how can I use them?

Legumes (also known as pulses) are a group of plant foods which aren’t just for vegetarians! They contain a wide variety of nutrients and are a very healthy and economical food for everyone to include as part of a balanced diet.

Legumes are high in dietary fibre which helps to keep our bowels healthy. They are also a good source of soluble fibre which can help lower blood cholesterol levels. Legumes are a source of carbohydrate and have a low glycaemic index (GI), which means they are broken down more slowly so you feel fuller for longer. This makes them a particularly good food for preventing and managing diabetes.

Legumes are also made up of protein, making them an ideal base to a vegetarian dish or a substitute for meat. Legumes are very cheap to buy, so including them as the main protein in your meals can save you money on your grocery bills.

Other benefits of legumes include:

  • High in B-group vitamins, iron, calcium, phosphorous, zinc and magnesium
  • Good source of folate, which is essential for women of child-bearing age
  • Good source of antioxidants
  • Low in saturated fat.

Examples of legumes include:

  • Split peas
  • Canalini beans
  • Kidney beans
  • Baked beans (navy beans)
  • Soybeans
  • Chickpeas
  • Four bean mix
  • Lupin
  • Red, green or brown lentils.

You can buy lentils in the supermarket either dry (which need to be soaked before cooking) or canned.

Including legumes into your healthy eating plan doesn’t mean you have to eat completely different meals. There are lots of ways you can include them in your favourite recipes.

Smart eating tips for eating more legumes

  • Add lentils to your own vegetable soup recipes or try these lentil patties as a summer barbecue alternative
  • Add chickpeas or soybeans to stir-fry dishes
  • Extend casserole dishes by adding beans and lentils. e.g. add kidney beans in a mince dish to make chile con carne
  • Snack on ‘chicknuts’ – oven roasted chickpeas
  • Use four bean mixes as a salad base and add lots of vegetables and a little oil-based dressing
  • Serve hummus (a low fat dip made from chickpeas) with vegetable sticks for a delicious snack
  • Small tins of baked beans make a great snack, a delicious breakfast served on toast or a great addition to a toasted sandwich
  • Beans, such as red kidney beans or soybeans are a great inclusion to lasagna or tacos
  • Legumes, like lentils or chickpeas make a great base for patties or vegetarian burgers
  • Substitute around 10% of wheat flour with lupin flour when baking to prepare higher fibre, higher protein and lower GI foods.
An Accredited Practising Dietitian (APD) can help you plan ways to include more legumes and provide you with recipes and meal ideas.

Legume

Legume, also called pod, fruit of plants in the pea family (Fabaceae). Most legumes are dehiscent fruits that release their seeds by splitting open along two seams, though some, such as peanuts (Arachis hypogaea) and carobs (Ceratonia siliqua), do not naturally open. The fruits come in a variety of sizes and shapes; many, however, are long and narrow and bear their seeds in a single line. The largest legumes are borne by the monkey ladder (Entada gigas) and can reach up to 2 metres (6.6 feet) in length. At maturity, legume fruits are usually dry and papery or hard and woody; the legumes of certain food crops, such as snow peas (variety of Pisum sativum), edamame (Glycine max), and green beans (Phaseolus vulgaris), are harvested while still green and fleshy.

  • garden pea podsGarden pea pods (Pisum sativum).Rasbak
  • Leaves and pods of honey locust (Gleditsia triacanthos).John H. Gerard/Encyclopædia Britannica, Inc.

Read More on This Topic human nutrition: Legumes Beans and peas are the seeds of leguminous crops that are able to utilize atmospheric nitrogen via parasitic microorganisms attached to…

Legumes furnish food for humans and animals and provide edible oils, fibres, and raw material for plastics. Many are grown for their edible seeds, which are high in protein and contain many of the essential amino acids. For important members of the legume family, see bean; chickpea; cowpea; lentil; pea; peanut; soybean; and tamarind.

  • tamarind fruitTamarind (Tamarindus indica) legume with pulp.© Feng Yu/Fotolia
  • guar legumesGuar, or cluster beans (Cyamopsis tetragonoloba), native to India.Surya Prakash

I Know I Should Eat them, but What are Legumes Anyway?

Legumes are a great source of protein and fiber. Legume consumption improves glucose control in diabetics and reduces risk for cardiovascular disease.

The Basics: Legumes include lentils, kidney beans, pinto beans, black beans, lima beans, black-eyed peas, garbanzo beans (chickpeas), split peas, soybeans (think edamame) and other beans. They are low in fat, cholesterol-free and great sources of protein, fiber and other nutrients such as iron, potassium, zinc and the important vitamin folate. Legumes are similar to meats, poultry, and fish in their contribution of protein and minerals and are considered part of the protein foods group. Many people consider beans and peas as vegetarian alternatives for meat. Because of their high nutrient content, legumes are recommended for everyone, not just vegetarians.

Not every pea or bean, even though technically a legume, has the same beneficial effects typically associated with legumes. Green peas, green lima beans, and green (string) beans are not considered by the United States Department of Agriculture (USDA) to be part of the beans and peas group. Why? Green peas and green lima beans are more similar to starchy vegetables like corn and potatoes. Green beans are grouped with other vegetables such as onions, lettuce, celery, and cabbage because their nutrient content is similar to those foods.

Now, there are even more reasons to consume legumes. A recent study published in the Archives of Internal Medicine shows that eating legumes daily improves glucose control in diabetics and improves risk factors for cardiovascular disease, primarily by lowering blood pressure.

Sounds like a “superfood” to me!

More Detail: The Archives of Internal Medicine reported that incorporation of legumes into the diet of non-insulin-dependent diabetics improved both glucose control and reduced calculated coronary heart disease risk. One-hundred-twenty-one patients with non-insulin-dependent diabetes were randomized to one of two dietary changes over three months: increase legumes by at least one cup a day or increase soluble fiber intake through consumption of whole-wheat products. Over three months, both diets reduced blood sugar, but those subjects on the legume-rich diet had significantly lower glucose levels. In addition, blood pressures and calculated coronary heart disease risk was significantly lower in the legume group.

David J.A., et al. “Effect of Legumes as Part of a Low Glycemic Index Diet on Glycemic Control and Cardiovascular Risk Factors in Type 2 Diabetes Mellitus: A Randomized Controlled Trial.” Arch Intern Med. 2012;172(21):1653-1660. doi:10.1001/2013.jamainternmed.871.

USDA basics on legumes: http://www.choosemyplate.gov/food-groups/vegetables-beans-peas.html

“Legumes” sounds like such a fancy word. Let’s clarify that we’re talking about beans, folks. Beans, lentils, peas, chickpeas, it’s all good… and good for you. Legumes are amazingly nutritious, high in protein and fiber, low in fat, and low in glycemic load.

Legumes for heart health

Scientific studies have definitively linked a diet high in legumes with a lower risk of developing obesity, diabetes, high blood pressure, high cholesterol, heart disease, or strokes. As a matter of fact, eating legumes every day can effectively treat these diseases in people who already have them. In one randomized controlled clinical study of over 100 people with type 2 diabetes, consuming at least one cup of legumes (beans, chickpeas, or lentils) every day for three months was associated with significant decreases in body weight (2.7 kilograms, about 6 pounds); waist circumference (a 1.4 centimeter decrease); blood sugar (a 0.5% decrease in HbA1c); cholesterol (an 8-point decrease in LDL, measured in mg/dl); and blood pressure (a 4.5-point decrease in systolic and a 3.1-point decrease in diastolic blood pressures, measured in mm Hg). All of these improvements are impressive! We’re talking about beans, not medicines with all those side effects, right? Right: you can check out the entire study here.

Similar findings have been reported from other studies. An analysis of eight randomized controlled clinical trials including data from over 550 participants with a wide variety of medical problems found that participants who consumed about a cup of legumes every day for 10 weeks had a significant decrease in systolic blood pressure (average 2.25 points). In another study, researchers combined data from ten randomized controlled trials representing over 250 participants who had been prescribed legumes every day for at least three weeks. The legumes varied: pinto beans, chickpeas, baked beans, lentils, and peas in amounts ranging from 1/2 cup to 2 cups. None of the participants was taking cholesterol-lowering medication, and yet the legume diets resulted in an average 8-point decrease in LDL cholesterol (that’s the low-density lipoprotein, the “bad” cholesterol). This is better than many people can achieve with pills! You can check out this study here.

How can beans have all of these benefits?

Legumes are high in fiber, specifically viscous soluble fiber, which not only slows their absorption in the small intestine, but also binds up certain molecules having to do with cholesterol. This makes legumes very low in glycemic index and load, meaning they result in lower blood sugars and less insulin released after eating them. This fiber also lowers cholesterol levels.

But wait — there’s more: not only are legumes high in fiber, they are also high in protein, making them very filling and satisfying, so people tend to eat less of other things. And they contain plenty of potassium, magnesium, folate, and other plant nutrients that are associated with lower blood pressure and improved cardiovascular health.

Despite all of this good evidence, people in the United States tend not to eat a lot of legumes. Given how healthy and economical beans, lentils, chickpeas, and peas are, we aim to help with some suggestions:

  • Chili: this popular dish can be super-healthy, too. Omit any meat and add extra beans (no-salt-added or low-salt canned beans work well).
  • Lentil or minestrone soup: hearty and warming soups can easily be made at home or purchased (be sure to purchase low-salt varieties).
  • Hummus: you can make this at home! Check out Dr. Rani Polak’s easy recipe below.

5 from 1 vote

Healthy Hummus

Ingredients

1 pound dry chickpeas, soaked overnight and drained (or use three 16-ounce cans chickpeas, which is equal to 4 cups, and omit the water and baking soda below)

3 quarts water

1 teaspoon baking soda

1/2 teaspoon Atlantic sea salt

1/2 teaspoon ground black pepper

1/3 cup tahini

The juice from 1/2 large lemon (about 2 tablespoons of juice)

2 cloves garlic

1/4 teaspoon cumin

Directions

Prepare dried chickpeas: In a large pot, combine chickpeas, water, and baking soda, and bring to a boil over high heat. Reduce heat to medium and cook, uncovered, for about 2 hours, until chickpeas are soft. Drain chickpeas (keep 1/2 cup of the cooking water), season with salt and pepper, and set aside to cool.

(If using canned, no need for the water and baking soda)

Transfer cooked or canned chickpeas, tahini, garlic, lemon juice, cumin and 1/2 cup of the cooking water to a food processor and puree. Adjust flavors with salt and pepper, and serve with olive oil.

Resources:

Can Pulses Play a Role in Improving Cardiometabolic Health? Evidence from Systematic Reviews and Meta-Analyses. Annals of the New York Academy of Sciences, March 2, 2017.

Prevention and Management of Type 2 Diabetes: Dietary Components and Nutritional Strategies. The Lancet, June 7, 2014.

Effect of Legumes as Part of a Low Glycemic Index Diet on Glycemic Control and Cardiovascular Risk Factors in Type 2 Diabetes Mellitus. JAMA Internal Medicine, November 26, 2012.

Effect of Dietary Pulses on Blood Pressure: A Systematic Review and Meta-Analysis of Controlled Feeding Trials. American Journal of Hypertension, September 7, 2013.

Non-soy Legume Consumption Lowers Cholesterol Levels: A Meta-Analysis of Randomized Controlled Trials. Nutrition, Metabolism and Cardiovascular Diseases, February 2011.

There’s a good chance you’ve heard of them and an even better chance you’ve had them on your plate at one point or another. But exactly what are legumes?

These vegetables pack in fiber and protein, plus an array of vitamins and minerals. They’re low in calories and a staple in vegetarian diets and vegan diets worldwide.

However, legumes have been laden with controversy because they contain compounds called antinutrients, which interfere with nutrient absorption. Luckily, there are methods that can be used to minimize the effects of these antinutrients, allowing you to reap the full benefits and nutrition of this versatile ingredient.

What Are Legumes?

So what are legumes? According to Merriam-Webster, the legumes definition is: “the fruit or seed of plants of the legume family (such as peas or beans) used for food.”

This legumes definition encompasses the fruit or seed of any plant in the family Fabaceae. This makes it a little tricky to define exactly what are legumes, as this family of plants includes a whopping 19,500 different species. (1)

Though there are thousands of different types of legumes, some of the most common legume varieties include:

  • Kidney beans
  • Peas
  • Soybeans
  • Peanuts
  • Green beans
  • Navy beans
  • Lentils
  • Chickpeas
  • Alfalfa

Note that peanuts are the only variety of nut included on this list. This is because, unlike other types of nuts, peanuts grow underground and belong to the Fabaceae family of plants.

Legumes have long been a dietary staple in many cultures, with some evidence showing that they began rapidly diversifying to form different species as many as 2 million to 4 million years ago in the Andes. (2)

Even today, however, beans and legumes are essential dietary components around the globe. From South America to Asia and beyond, millions of people rely on the affordability, convenience and nutritional density of legumes each and every day.

What Are Legumes Good For? Benefits of Legumes

1. High in Protein

So what are legumes good for? For starters, most legumes are packed with protein and are considered one of the best sources of plant-based protein.

Chickpeas and navy beans, for example, each contain 15 grams of protein per one-cup serving while white beans contain 19 grams of protein for the same amount. (3, 4, 5)

Protein is a crucial part of the diet and critical to cellular function and muscle growth. (6)

For this reason, legumes become especially important in vegan and vegetarian diets and are often used as a staple source of protein.

When it comes to weight loss, eating enough protein can also encourage satiety and keep you feeling full while increasing your metabolism and the amount of calories you burn after a meal. (7)

Including even just one serving of legumes in your diet each day can be an excellent way to help you meet your protein needs.

2. Promote Regularity

In addition to their impressive protein content, legumes also contain a hearty dose of dietary fiber.

One cup of cooked lentils, for instance, contains 16 grams of fiber, or up to 64 percent of the daily recommended value. (8)

When you eat fiber, it moves through your digestive tract slowly and adds bulk to the stool to aid in its passage. (9)

This is especially beneficial when it comes to constipation. In fact, increasing your fiber intake is one of the first lines of defense to help get things moving.

One analysis published in 2012 looked at five different studies and found that increased dietary fiber intake was able to significantly increase stool frequency in participants with constipation. (10)

However, it’s important to keep in mind that you should increase fiber intake slowly and make sure to drink plenty of water as well. Sudden increases in fiber intake can cause unpleasant symptoms like gas, cramps or bloating.

3. Aid in Weight Loss

If you’re looking to shed some pounds, you might want to consider adding a few servings of legumes into your diet.

Not only are legumes high in fiber and protein, both of which can help promote satiety and ward off hunger, but legume consumption has also been associated with weight loss.

One study published in the Journal of the American College of Nutrition followed 1,475 participants over a span of eight years. Researchers found that those who ate beans regularly had a lower body weight, smaller waist size and a 22 percent lower risk of obesity. (11)

Legumes are also very nutrient-dense foods, meaning they are low in calories but cram tons of vitamins, minerals and nutrients into each serving. This makes it easier to optimize the calories that you’re taking in on a weight-loss diet.

4. Boost Heart Health

It goes without saying that the heart is one of the most crucial organs in the body. It pumps out blood to all of the tissues in your body and supplies them with the oxygen and nutrients they need to function and thrive.

Naturally, protecting the health of your heart is critical, as heart disease is the most common cause of death worldwide. (12)

Paired with an otherwise healthy diet and active lifestyle, adding a serving or two of legumes to your plate each day can have a big impact on heart health.

A 2011 study showed that a diet rich in legumes can decrease both total and bad LDL cholesterol. (13)

Another study published in the American Journal of Clinical Nutrition found that eating legumes was associated with a decreased risk of heart disease. (14)

Other research has found additional heart-healthy benefits of legumes, such as decreasing triglycerides, blood pressure and inflammation. (15, 16)

5. Contain Important Vitamins and Minerals

Besides being rich in both protein and fiber, legumes are chock-full of vitamins and minerals as well.

Most legume varieties are high in micronutrients like folate, iron, magnesium, phosphorus, manganese and potassium.

A cup of lentils, for example, provides 90 percent of your daily folate needs and 37 percent of the iron you need in a day.

For this reason, legumes are an excellent way to round out a diet that may be lacking in certain nutrients.

Vegetarians and vegans, for instance, may especially benefit from increasing legume intake to ensure that their needs for these important micronutrients are met.

6. Stabilize Blood Sugar

So what are legumes good for besides providing a concentrated dose of protein, fiber, vitamins and minerals; improving heart health; preventing constipation; and helping you drop a few pounds?

In addition to all of the previously mentioned impressive health benefits, legumes are also excellent at regulating your blood sugar. The high amount of fiber found in legumes works to slow the absorption of sugar in the bloodstream and maintain blood sugar levels.

A 2014 study with over 2,000 participants found that blood sugar levels, among other factors, were lower in those who regularly ate legumes compared to those who didn’t. (17)

Coupled with low-glycemic fruits, non-starchy vegetables and a good source of protein, legumes can be a healthy addition to the diet and can help keep blood sugar stable.

Side Effects of Legumes

Although legumes are loaded with health benefits, there are also some drawbacks to including them in your diet that should be considered.

Legumes contain “antinutrients,” or compounds that can interfere with the absorption of important micronutrients like iron and calcium.

The most prevalent antinutrient found in legumes is phytic acid, the major storage form of phosphorus, which is found in foods like cereals, legumes and nuts. The problem is that phytic acid can bind to and prevent the absorption of certain minerals, including iron, zinc calcium, magnesium and manganese. (18)

Over time, this can cause nutrient deficiencies for individuals who frequently eat legumes. However, keep in mind that this is much more likely to affect vegetarians than meat eaters. (19) In fact, nutrient deficiencies as a result of phytic acid really only affect those with a diet composed mostly of cereals, legumes and grains. (20)

Lectins are another type of antinutrient found in legumes. Lectins resist digestion and can even damage the lining of the gastrointestinal tract. (21)

Fortunately, by practicing proper preparation techniques, the harmful effects of the antinutrients found in legumes can be minimized.

The Best Way to Eat Legumes

To take full advantage of the health-promoting effects of legumes, proper preparation is key. Certain cooking methods can reduce the negative effects of antinutrients while also enhancing the nutrient profile.

Sprouting is a process that involves soaking legumes between eight to 24 hours and then straining them and leaving them out to sprout. Not only does sprouting help slash phytic acid, but it can also boost the amount of other beneficial nutrients.

One 2015 study showed that sprouting cowpeas reduced phytic acid by four to 16 times. It also increased the amount of protein by 9 percent to 12 percent, increased vitamin C by four to 38 times and improved protein digestibility by 8 percent to 20 percent. (22)

Fermentation is another process that can significantly improve the nutritional quality of legumes. This typically involves combining seeds with yeast and an acid to create healthy bacteria that can help break down hard-to-digest foods in the gastrointestinal tract. Studies show that fermenting legumes can make proteins easier to digest and can cut the amount of phytic acid found in foods. (23)

By soaking, sprouting and fermenting your legumes, you can ensure that you’re optimizing the nutritional content of your legumes, increasing absorption and preventing potential negative side effects.

Read Next: Lima Beans Nutrition Benefits Pregnancy, Weight Loss & More

What Are Legumes to Eat and Legumes to Avoid?

What are the best legumes to eat? Beans, lentils and peas are the main classes of legumes and are all relatively comparable when it comes to nutrition.

Keep in mind, though, that some forms of these legumes may be healthier than others. When comparing dried versus canned beans, for example, canned beans tend to be laden with excess sodium and are not exactly heart-healthy.

While dried legumes are preferable, they can take longer to prepare and may not be as convenient or efficient. If you do opt for canned varieties of legumes, make sure they’re labeled “low-sodium,” and be sure to rinse off any extra salt before serving.

Most types of legumes are safe for consumption and generally don’t pose a risk to health. However, eating raw or uncooked beans can actually be very dangerous.

Kidney beans, in particular, contain phytohemagglutinin, a type of lectin that can be toxic when consumed in high amounts. In fact, there have been many reported cases of phytohemagglutinin poisoning as a result of eating raw or undercooked kidney beans. (24)

Luckily, cooking inactivates phytohemagglutinin and negates its toxic properties. For this reason, it’s important to avoid raw beans and stick to enjoying beans that have been properly cooked and prepared.

How Much Should You Eat?

Although legumes are a dietary staple in many parts of the world, they aren’t quite as common in the United States. In fact, despite the many health benefits of legumes, only an estimated 8 percent of Americans eat legumes on any given day. (25)

Though there are no clear-cut recommendations of how many servings of legumes you should eat, incorporating a few servings into your diet each week may have favorable effects on your health.

Vegetarians may want to consider increasing this amount and including sprouted or fermented legumes more regularly in their diets to help meet fiber and micronutrient needs.

However, for most people, throwing in a few one-cup servings of peas, beans or lentils can help fill in the gaps in an otherwise healthy diet.

Here are a few nutritious recipes that can help increase your legume intake:

  • Sprouted Garbanzo Burgers
  • Crunchy Vegetable and Alfalfa Sprout Wraps
  • Sprouted Lentil Salad with Farro and Raw Vegetables

You can also try my Green Bean Recipes, Turkey Chili with Adzuki Beans Recipe and Tangy Bean Salad Recipe.

Precautions

Legumes are a tasty and nutritious addition to the diet for most people. However, some people may want to limit their intake.

For those following a Paleo diet, legumes are on the list of foods that should be avoided due to their phytic acid content.

Additionally, because legumes do contain a good chunk of carbs, those with diabetes should be mindful about what else is on the menu when including legumes in their diets. Pair legumes with non-starchy vegetables, low-glycemic fruits and lean sources of protein for a well-balanced, blood sugar-steadying meal.

Some people may also be allergic to certain types of legumes. Peanuts, for example, are a common allergen and can cause symptoms like hives, wheezing and even tightening of the throat. If you experience any negative symptoms after eating legumes, be sure to discontinue consumption and consult your doctor immediately.

Finally, make sure to increase legume intake slowly and drink plenty of water. Increasing your fiber intake too quickly can lead to symptoms like cramps, gas and bloating.

Final Thoughts on What Are Legumes

What are legumes? They’re an incredibly diverse group of foods with varying nutrient profiles, flavors and uses. In fact, this makes it difficult to define what are legumes because there are thousands of different species cultivated around the globe.

Although legumes boast a wide array of health benefits, they also contain compounds like phytic acid which can impair the absorption of certain minerals.

However, by practicing proper preparation, the negative effects of phytic acid can easily be minimized.

While increasing your legume intake may not be for everyone, including legumes as part of a nutritious diet can provide many essential nutrients and may be beneficial to your health.

What are legumes good for? The top six benefits of legumes are:

  1. Being high in protein
  2. Promoting regularity
  3. Aiding in weight loss
  4. Boosting heart health
  5. Providing important vitamins and minerals
  6. Stabilizing blood sugar

Read Next: Sprout Guide: How to Sprout Grains, Nuts & Beans

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