Fact checked by Nick Blackmer
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- New research links legume and soy consumption with a lower risk of high blood pressure.
- Specifically, eating about 100 grams of legumes or 60 to 80 grams of soy products per day may help reduce the risk of hypertension.
- However, the study cannot prove that soy and legume consumption directly reduces hypertension risk.
What you eat can have a big impact on blood pressure, and a recent review suggests that a diet rich in two food groups could help prevent it from getting too high: legumes and soy products. And when it comes to eating these foods for blood pressure benefits, quantity matters, according to the new paper.
Why Researchers Examined This—and What They Did
High blood pressure is incredibly common, affecting 1.4 billion people worldwide, and is a major risk factor for heart problems. Previous studies have suggested a link between legumes and soy with reduced blood pressure, but researchers wanted to “clarify the association,” they wrote in their paper, which was published in the journal BMJ Nutrition, Prevention & Health.
The team examined 12 existing studies investigating blood pressure and consumption of legumes like beans and chickpeas and soy products like tofu and tempeh. In each study, researchers observed participants over time rather than instructing them to consume a specific amount of legumes or soy. The studies ranged in size from about 1,100 to 88,500 participants and were conducted in several countries, including the U.S., France, the United Kingdom, China, Iran, South Korea, and Japan.
How Much Legumes and Soy Do You Have to Consume For Potential Benefits?
After adjusting for factors that could influence blood pressure, such as diet, exercise, and age, a few trends emerged: People who ate the most legumes had a 16% lower risk of hypertension, and those who ate the most soy had a 19% lower risk compared with those who ate the least.
Specific daily quantities were also tied to reduced risk of hypertension. For legumes, 100 grams per day was associated with a 12% to 14% lower risk, while up to 170 grams a day was associated with a 30% lower risk. Those amounts translate to roughly a half-cup to one cup of cooked beans, peas, or lentils.
Consuming 60 to 80 grams (or about 2 to 3 ounces) of soy per day—about a half-cup of edamame or a little less than one serving of tofu—was linked to a 28% to 29% reduction, which remained steady even with higher intake.
For people in the U.S. and Europe, these quantities are significantly higher than what most currently consume. The study noted that average legume consumption in these regions is only about 8 to 15 grams per day.
The Research ‘Advances the Field’—But Has Limitations
According to Sirisha Vadali, MD, a board-certified cardiologist and advanced lipidologist based in Arizona, the study “strongly” supports the idea that legumes and soy are beneficial for preventing hypertension. But while the findings may not change recommendations, she said they “meaningfully advance the field” in two ways: by showing dose-response relationships and by rating the evidence as probably causal.
However, because this is an analysis of observational studies, the research cannot definitively conclude a cause-and-effect relationship between soy and legume consumption and reduced hypertension risk. Another limitation, acknowledged by the authors, is the variation among the populations studied and the types of legumes consumed, which makes it difficult to determine whether black beans offer more benefit than chickpeas, for example, or whether tofu is more effective than tempeh.
Why Legumes and Soy May Help Lower Blood Pressure
Dagfinn Aune, PhD, one of the study’s authors and a research fellow in the department of epidemiology and biostatistics at Imperial College London’s School of Public Health, said that legumes and soy contain several nutrients that could account for their blood pressure benefits.
Fiber is particularly notable. It can lower cholesterol levels and keep blood sugar levels steady, two factors that reduce the risk of hypertension. It also benefits gut health by serving as a prebiotic that helps gut bacteria produce beneficial short-chain fatty acids. Emerging research has suggested a link between gut health and blood pressure regulation.
Soy also contains two types of isoflavones, genistein and daidzein, Aune said. Genistein may reduce various cardiovascular risk factors, while daidzein has anti-inflammatory and antioxidant properties and may offer protective cardiovascular benefits.
It’s also possible that the blood pressure benefits are a secondary effect of another outcome associated with legume and soy consumption: weight loss. “Both legumes and soy have been associated with less weight gain, and obesity is a major risk factor for hypertension,” Aune told Health.
Simple Ways to Add More Legumes and Soy to Your Diet
Legumes and soy-based foods are versatile and can be incorporated into every meal of the day. To eat more soy, Craig Basman, MD, FACC, FSCAI, a board-certified cardiologist and associate director of the Structural & Congenital Heart Program at Hackensack Meridian Medical Group, suggested starting with tofu. Buy it firm and crumble it into a stir-fry or chili, or opt for silken tofu, which you can blend into dressings or desserts. Edamame is another easy option—try steaming it and topping it with a sprinkle of salt.
As for legumes, a can of rinsed black beans can go a long way. Try adding them to your favorite soup or salad. Hummus, made from chickpeas, is another good option, or you can blend white beans into smoothies for a creamy texture, Basman said.
Just keep in mind that beans can cause gas, bloating, or other gastrointestinal discomfort in people who aren’t used to eating them. To avoid this, Basman suggested:
- Starting with smaller portions: “Begin with just a couple of tablespoons of beans a day, and gradually increase the amount over a few weeks.”
- Rinsing canned beans: A simple rinse washes away some of the sugars that can cause gas.
- Soaking dry beans: For best results, soak dry beans overnight and then cook them in fresh water.
- Drinking plenty of water: Water helps fiber move more easily through the digestive system.
What’s powerful about the study findings "is how achievable they are,” Vadali said. “Legumes and soy aren’t exotic superfoods. Better yet, they’re affordable, familiar, and adaptable. For [hypertension] prevention, the biggest gains come from moving intake from rarely to regularly.”
