Snacking on nuts may do more than just satisfy a craving—it could also support healthy blood pressure. A new analysis found that eating roughly a serving of nuts a day—the equivalent of about a handful—was associated with a lower risk of developing high blood pressure, a major risk factor for heart disease.

While the study doesn’t prove that nuts directly prevent high blood pressure, it adds to a growing body of research suggesting that nuts may have unique benefits for the heart.1

What the Study Found

Researchers analyzed eight existing studies involving more than 20,000 cases of high blood pressure, also called hypertension. These studies were observational, meaning they looked at people’s behaviors and health outcomes over time. (That’s different from randomized controlled trials, which measure the effects of individual variables and are considered the gold standard for determining cause and effect.)

After analyzing the relationship between nut consumption and the risk of developing hypertension, the researchers found that nut eaters appeared to have an edge.

People who consumed the most nuts had a 16% lower relative risk of hypertension than those who consumed the least. Eating about 30 to 35 grams—about one ounce, or one serving—per day was associated with about a 26% lower risk.

The benefits seemed to have limits, however, with the effect leveling off between 25 and 35 grams per day.

“So for now it seems that one serving per day may be sufficient to reduce risk,” study author Dagfinn Aune, PhD, a research fellow at the Department of Epidemiology and Biostatistics at the School of Public Health of Imperial College London, told HEALTH.

What’s In a Nut?

The research didn’t break down the benefits by nut type—or prove that nuts directly lower blood pressure—but all nuts share a similar nutritional profile that could help explain the association.

Nuts “are packed with essential nutrients that directly support vascular health—specifically magnesium, potassium, and healthy unsaturated fats,” said Craig Basman, MD, FACC, a cardiologist with Hackensack University Medical Center.

Nuts also contain L-arginine, an amino acid the body uses to produce nitric oxide. Nitric oxide helps relax and dilate blood vessels, which can reduce the resistance the heart has to pump against, Basman explained.2

Fiber is another important nutrient in nuts. Some types, such as almonds, are especially rich in soluble fiber. Soluble fiber acts as a binding agent, said registered dietitian Briana V. Reamer, MS, RDN, LDN. In the digestive tract, it binds to cholesterol and helps carry it out of the body. With less cholesterol circulating in the blood, arteries can stay more flexible, allowing blood to flow more freely and helping blood pressure to remain low.

Does the Type of Nut Matter?

While this study didn’t offer any insights into specific nut types, previous research suggests that some may be more beneficial for blood pressure than others.

“From a clinical data standpoint,” Basman said, “pistachios and walnuts currently have the most robust scientific backing for actively lowering blood pressure.”

For example, a 2015 systematic review and meta-analysis found that pistachios beat out other nuts for lowering both systolic (the top number) and diastolic (the bottom number) blood pressure.3 Several studies have also found that walnuts may lower blood pressure in certain groups, including older adults and people at risk of heart disease.4

It’s also worth noting that nuts’ potential blood pressure benefits may not hold up when they’re heavily salted or candied, and that some types of nuts are more calorie dense than others. That’s something to consider if you’re managing your weight because one ounce of nuts—the amount linked with blood pressure benefits—looks different depending on variety.567

“Utilizing mindfulness and portion control is still needed to maintain weight with this calorie-dense food item,” Reamer said.

Nuts Aren’t a Substitute for Blood Pressure Treatment

Ultimately, a handful of nuts each day can be a healthy choice—but it isn’t a substitute for an overall heart-healthy lifestyle or medical treatment of hypertension.

“The biggest takeaway here is to view nuts as part of a comprehensive lifestyle strategy, rather than a magic bullet,” Basman said.

If you include nuts as part of your diet, continue to follow your doctor’s guidance for managing your blood pressure and protecting your cardiovascular health.