Harvard Health Blog
Love those legumes!
"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.
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 [Legumes] 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 [Legumes] 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.
About the Authors
Monique Tello, MD, MPH, Contributor
Rani Polak, MD, Chef, MBA, Contributor
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