By Rachael Link, MS, RD
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:
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.
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.
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.
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.
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.
Another study published in the American Journal of Clinical Nutrition found that eating legumes was associated with a decreased risk of heart disease. (14)
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.
What Are Legumes to Eat and Legumes to Avoid?
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
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:
- Being high in protein
- Promoting regularity
- Aiding in weight loss
- Boosting heart health
- Providing important vitamins and minerals
- Stabilizing blood sugar
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