When you think March, you think green: the arrival of spring, new grass, St. Patrick’s Day, and even green beer. But March is also National Nutrition Month, and this year’s theme is “Savor the Flavor of Eating Right.”
Most Americans are not eating right – that is, meeting dietary guidelines set by the USDA and the Department of Health & Human Services (HHS), and need more guidance in how to eat a more balanced diet.
But where do you begin? You know that adding more green-colored foods to your diet is a great way to eat more healthfully, but we want to encourage you to “go green” in a different way – by making room for green legumes!
Legumes & Pulses & Beans, Oh My!
Is a legume a grain? Or is it a bean or vice versa? And what in the world is a pulse? There seems to be a lot of confusion about how these healthy foods are classified, so let’s start with the basics.
Legumes are the pod-grown edible seeds of plants in the family Fabaceae, a plant group that includes beans, string beans, peas, lentils, soybeans, peanuts, and sprouted varieties like bean sprouts, alfalfa and clover. There are more than 13,000 different species of legumes, and they are eco-friendly, sustainable crops that replenish nitrogen in the soil, reducing the need for chemical fertilizers.
Legumes can be divided into two basic groups: immature and mature varieties. Immature legumes are what we would consider “fresh” legumes, or legumes that have not been dried. Green beans, fresh peas, fresh soybeans, and bean sprouts are some examples.
Mature legumes that are harvested from the pod in their fully developed, dried, form are pulses. Those dried beans, peas, chickpeas, and lentils you see at the grocery store? They are pulses, and they are a part of the legume family. The most commonly consumed pulses include split peas, butter beans, broad beans, chickpeas, lentils, black beans, and kidney beans.
Simply put, all beans, peas, lentils, soybeans, and the like are legumes, but when they are dried, they are called pulses. Mystery solved!
Legumes – A Dieter’s Delight
Legumes are a superfood rich in complex carbohydrates, protein, and fiber, and they tend to be a low-calorie, high-satiation food that provides steady, long-lasting energy. Most are rich in folic acid, calcium, iron, potassium, zinc, and antioxidants –a 1/2-cup serving of cooked black beans delivers 32%, 15% and 14% of the daily values for folate, magnesium and thiamine, respectively, and about 10% each of the daily values for iron and potassium.
They also provide prebiotics, substances that promote the growth of beneficial bacteria in the intestine, and many varieties contain protease inhibitors, compounds believed to suppress cancer cells and slow tumor growth.
Furthermore, they fulfill three of the six parts of the Healthy Eating Plate by being both a vegetable and protein, and by being a source of healthy, plant-based oils.
Rich Source of Protein
With the exception of meat, poultry and fish, legumes are higher in protein per serving than other types of food. Their high protein content – the highest of any vegetable and twice that of grains – results from the nitrogen they add to the soil. They are the most common protein source in many countries. For many vegetarians who do not eat meat, they act as a popular meat substitute because they are inexpensive yet have a similar vitamin and mineral profile. But unlike meat, legumes have the added benefit of being cholesterol-free and having little to no saturated fat.
A one-cup serving of beans, peas and lentils generally delivers about 15 grams of protein. And according to the National Academy of Sciences Institute of Medicine (IOM) guidelines, women should consume 46 grams of protein and men should consume 56 grams of protein daily, so a one-cup serving of legumes would provide nearly a third of a day’s protein requirements.
However, with the exception of soybeans, the proteins in legumes are considered “complementary,” meaning that they must be eaten together with grains, seeds or nuts or on the same day to provide all nine essential amino acids. In addition, the body uses incomplete proteins more efficiently when combined with complete proteins like dairy, eggs, meat, or fish.
Promotes Digestive Health
The bean’s reputation as a “musical fruit” is not without merit, given that legumes are a top source of fiber. They contain both insoluble fiber, which prevents constipation, and soluble fiber, which helps keep blood sugar levels balanced and reduces cholesterol in the bloodstream.
Insoluble fiber, or “roughage,” cannot be digested by the body and thus adds bulk to stool; soluble fiber draws in water and inhibits watery stools. Together, they prevent constipation by keeping things moving in your digestive tract and also prevent or treat conditions such as diverticulitis, hemorrhoids, and irritable bowel syndrome. In addition, consuming beans several times a week may decrease the risk of colorectal adenomas (polyps), which may then lower the risk of colorectal cancer.
Regulates Blood Sugar and Promotes Heart Health
The American Diabetes Association, the American Heart Association and the American Cancer Society all endorse legumes as a key food in preventing disease and maintaining good health. The fiber, protein and nutrients they provide help with blood sugar regulation more than almost any other food group, making them a good food for diabetics and those concerned with maintaining stable insulin response.
Legumes are also great for heart health. Their high fiber content helps to lower cholesterol and triglyceride (blood fat) levels, and their high levels of folate help to prevent the accumulation of homocysteine, an amino acid that contributes to heart attack and stroke risk. A daily serving of cooked beans may lower blood cholesterol by as much as 18 percent, according to one study.
In fact, fiber plays such a large role in preventing cardiovascular disease that the IOM determined the daily recommended intake – 25 grams for women and 38 grams for men – based on the amount needed to protect against coronary heart disease. While the amount of fiber in different legumes varies, most provide about 16 grams per one-cup serving.
Helps With Weight Loss
The trio of protein, fiber, and complex carbohydrates in legumes also helps with weight loss and weight maintenance. They are a low-calorie, low-fat food that fills you up and helps you feel fuller, longer, preventing unnecessary snacking or overeating. One cup of most legumes contains 1 gram or less of total fat and just 190-300 calories.
Green Beans, Lentils & Peas
This month try incorporating some of these popular green legumes into your diet – green beans, soybeans, lentils, green peas, sugar snap peas and snow peas.
Green Beans. Also known as snap beans, string beans, French beans, or haricot vert, green beans are medium length, green pods containing small green seeds. The entire pod is edible, along with the beans inside.
One cup of green beans has about 34 calories, 8 grams of carbohydrate, 4 grams of fiber, 2 grams of protein, and are a source of vitamin C, vitamin K, magnesium, vitamin A, folate and potassium.
The vitamin A found in green beans is primarily from the phytonutrients lutein, zeaxanthin and beta carotene. The carotenoid content of green beans is comparable to several other carotenoid rich vegetables like carrots and tomatoes, although the vibrant carotenoid colors are hidden by the concentrated chlorophyll that gives most green beans their vibrant emerald color.
To prepare fresh green beans, snap the tough ends off before cooking them. An easy way is to line them up on a cutting board and cut off all the ends with one chop. For maximum nutritional value, eat green beans raw or lightly steamed; they can also be lightly sautéed in olive oil as a side dish. If unavailable fresh, frozen green beans retain much of the nutritional benefits, but try to avoid canned, as they are high in sodium and lose some of their nutritional value and texture during the canning process.
Soybeans. Also known by their Japanese name, edamame, the soybean is a popular appetizer in sushi bars. They are also the source of other healthy foods such as tofu, soymilk, soy sauce, and meat alternatives. Soybeans grow in a pod and most only eat the bean found inside.
A cup of cooked green soybeans has about 254 calories, 19 grams of carbohydrate, 8 grams of fiber and 22 grams of protein. Soybeans are a very good source of vitamin C, thiamin, folate and manganese. These beans are also a good source of numerous minerals including magnesium, potassium, calcium and iron. Like other beans and seeds, soybeans are a good source of polyunsaturated Omega-6 fatty acids, with close to 5g per cup.
Soybeans can come in fresh, frozen, or dried form. Fresh soybeans can be boiled or steamed with or without salt and eaten as is. They can also be added to salads, sautéed as a side dish, or formed into meat-free patties. Another popular preparation is roasting whole soybeans and eating them like nuts. Dry soybeans can be soaked and boiled and then roasted, baked, or prepared much like other beans.
Lentils. Lentils are small, flat, lens-shaped legumes that come in a variety of colors including green, brown, yellow, orange, red, and black. French green lentils are the most delicate but are widely considered one of the best types due to their pleasing, lightly peppery flavor.
A cup of cooked lentils has about 230 calories, 40 grams of carbohydrate, 16 grams of fiber and 18 grams of protein. Lentils are an excellent source of folate, the B-vitamin women take during pregnancy to prevent birth defects. Lentils are also a good source of the minerals manganese, iron, copper, zinc and the vitamins thiamin and B-6.
Lentils are most often found in dried form, but they can also be found in cans or prepared packages. If preparing dried lentils is daunting or too time-consuming for your busy lifestyle, canned or prepared lentils are still a good option as rinsing the beans with water can reduce up to 40% of the sodium; you can also opt to buy low-sodium canned beans to further cut down on the sodium content. Lentils are commonly used in soups, stews, added to salads, or used to make deliciously filling meat-free burgers.
Other varieties of green-colored beans to try include lima beans, fava beans, and green split peas.
Green Peas. When you think of peas, you most likely think of the English peas, or garden peas, that you find at your local grocery. They grow in a tough, inedible pod, but the peas inside are round and green with a sweet, fresh flavor.
A cup of raw peas has about 117 calories, 21 grams of carbohydrate, 7 grams of fiber, and 8 grams of protein. Green peas are an excellent source of vitamin C and a good source of vitamin K, manganese, thiamin, folate and vitamin A.
Peas are found fresh, frozen, or canned, and may be eaten raw or cooked. You can boil them, steam them or eat them raw. Add them raw or cooked to salads, puree them into soups both hot and cold, use them in a sauce, or steam or sauté them as a side dish.
Sugar Snap Peas and Snow Peas. Sugar snap peas are a type of pod pea found in an edible rounded pod. Snow peas are also an edible pod pea, but they grow in long, flat green pods that contain several tiny, green peas. They have a fresh, sweet flavor, making them a popular healthy snack.
Sugar snap peas and snow peas are nutritionally similar. One cup of raw sugar snap peas or snow peas has about 41 calories, 7 grams of carbohydrate, 3 grams of fiber, and 3 grams of protein. They are an excellent source of vitamin C and a good source of vitamin K and vitamin A.
While they can be found fresh or frozen, sugar snap peas and snow peas are most often eaten in their fresh form. Sugar snap peas are usually eaten raw on salads or with dips, but they can be sautéed or added to a stir-fry. Snow peas are also eaten raw, but they can be tossed in a stir-fry or sautéed for added color and nutrition.
Go Green this March!
We could all use a little more green in our lives – green legumes, that is. Recently, the United Nations General Assembly voted to declare 2016 the International Year of Pulses (IYOP), so get a jump start on this food trend and make room for legumes in your diet today. Your body will look and feel better for it!
Last updated February 29, 2016
David H. Rahm, M.D. is the founder and medical director of The Wellness Center, a medical clinic located in Long Beach, CA. Dr. Rahm is also president and medical director of VitaMedica. Dr. Rahm is one of a select group of conventional medical doctors who have education and expertise in functional medicine and nutritional science. Over the past 20 years, Dr. Rahm has published articles in the plastic surgery literature and educated physicians about the importance of good peri-operative nutrition.