Nearly half of all adults in the United States have high blood pressure, or hypertension, according to the latest data from the Centers for Disease Control and Prevention, but only 1 in 4 have it under control. If you're one of them, you've likely heard that you should limit your salt intake. But eating less salt isn't the only diet change that can help with hypertension. The Dietary Approaches to Stop Hypertension (DASH) diet is a well-researched eating pattern for both preventing and treating high blood pressure. In addition to reducing dietary sodium, the DASH diet emphasizes filling your plate with more fruits, vegetables, whole grains, nuts, seeds, low-fat dairy products and lean meat.
And when it comes to produce, one vegetable in particular is a standout star when it comes to lowering blood pressure: dark leafy greens. Keep reading to learn why eating arugula, cabbage, kale, spinach and other greens can make a big impact on blood pressure.
Blood Pressure Benefits of Dark Leafy Greens
High in Minerals
According to 2019 research published in Nutrients, three specific minerals that can have a positive impact on blood pressure are potassium, calcium and magnesium. Dark leafy greens are a good source of all three of these nutrients. Magnesium helps manage blood pressure by increasing nitric oxide levels, which helps blood vessels relax. And calcium can influence blood pressure through its actions on the smooth muscle cells that line artery walls. Just 1 cup of cooked spinach has 37% of the Daily Value of magnesium and almost 10% DV of calcium.
Potassium plays a large role in blood pressure management, as it helps the body eliminate excess sodium through urine, which can reduce water retention and blood volume and lead to lower blood pressure. A 2020 review in Hypertension noted that populations who consumed a higher-potassium, lower-sodium diet had lower rates of hypertension. However, most adults don't score the Daily Value of 4,700 milligrams of potassium. Including at least one serving of dark green leafy vegetables daily can help you reach that DV for potassium.
Source of Dietary Nitrates
Dark leafy greens like cabbage, chard, spinach, kale and arugula are high in nitrate, a compound naturally found in soil, water and food. Bacteria and enzymes in the body convert the nitrate in plant-based food like leafy greens into nitrous oxide which acts like a messenger, telling blood vessels to relax and dilate and thereby lowering blood pressure. (It's important to note that manufacturers also add nitrate to processed meats as a preservative—which may turn into harmful nitrosamines. But it acts very differently in the body than plant-based nitrate.)
In a 2021 Danish cohort study published in the European Journal of Epidemiology, participants who consumed at least 1 cup of green leafy vegetables daily had a lower systolic blood pressure at baseline and a significantly reduced risk of cardiovascular disease events like heart failure and stroke, compared to those who ate less green leafy vegetables. And a 2018 meta-analysis published in Nutrition Reviews found that consuming high-nitrate plant foods can significantly lower systolic blood pressure as well as improve other cardiovascular disease factors like endothelial function.
High in Vitamin C
More research is needed to completely understand the relationship between vitamin C and blood pressure, but there are some theories about how it may be beneficial. One factor that increases your risk of developing high blood pressure is oxidative damage to blood vessels. Oxidation is a normal and necessary process, but can become harmful if there is an imbalance between unstable compounds called free radicals and antioxidants like vitamin C. If there aren't enough antioxidants available, free radicals will begin to cause damage to tissues like your blood vessels, so eating more antioxidant-rich foods can help keep free radicals in check.
Vitamin C also works hand in hand with the nitrate in dark leafy greens to increase the blood pressure benefits. As noted previously, the body makes nitrous oxide, a chemical messenger that tells blood vessels to relax, when it breaks down nitrate from food. Vitamin C helps this process along by increasing the activity of the enzyme that converts the nitrate in food into nitrous oxide.
What's more, a 2020 meta analysis published in Cardiovascular Therapeutics found that those with high blood pressure had significantly lower levels of vitamin C in their blood than those with normal blood pressure. While the evidence for taking vitamin C supplements for blood pressure is inconclusive, there is no harm in eating a diet with more fruits and vegetables which are high in the vitamin. A cup of cooked greens like spinach or kale provides at least 15% of the DV for vitamin C.
Rich in Carotenoids
Dark green leafy vegetables are high in fat-soluble pigments called carotenoids that have been associated with many protective health benefits. Like vitamin C, carotenoids also act as an antioxidant, helping to reduce oxidative stress that can contribute to an increased risk of high blood pressure. A 2019 review of observational studies published in the Journal of Hypertension looked at carotenoid intake specifically in relation to blood pressure and noted that people with higher intakes of carotenoid-rich foods (such as fruits and vegetables like dark leafy greens) were less likely to have hypertension.
Good Source of Fiber
Just 5% of U.S. adults are getting the recommended amount of fiber in their diet, but eating enough of this nutrient comes with a whole host of health benefits including lower blood pressure. A 2020 systematic review published in BMC Medicine found that even after a diagnosis of heart disease or high blood pressure, increasing the fiber in your diet can significantly improve both. Dark green leafy vegetables can be a great source of fiber, especially when cooked. For example, 1 cup of cooked spinach has 4 grams of fiber.
Bottom Line
Adopting a diet that incorporates more fruits and vegetables can go a long way toward helping you lower your blood pressure. Make at least one of your daily vegetable servings a dark leafy green like arugula, cabbage, kale or spinach for potentially greater blood pressure benefits. A serving of leafy greens is 1 cup of raw greens or ½ cup cooked greens. Easily increase your intake of greens by adding them to soups, tossing a handful into smoothies or packing a salad for lunch at work.