High blood pressure (hypertension) is the single largest burden to global health, just ahead of tobacco smoking (1). In the United States, about 33% of adults have high blood pressure (140/90 mmHg or higher) and another 33% have prehypertension (systolic 120-139 mmHg or diastolic of 80-89 mmHg) (2). Keeping our blood pressure below 120/80 mmHg is considered “normal”, but the ideal blood pressure for humans may be as low as 100/60 mmHg, which is seen in populations eating no processed foods (3).
There are some non-modifiable risk factors for high blood pressure, such as race (high blood pressure is more common among African-Americans) and family history. Age is often considered a non-modifiable risk factor for high blood pressure, but this is not true, as there are numerous populations whose blood pressure does not budge as they age (due to their healthy lifestyle) (3). All other risk factors for high blood pressure are within our control. Maintaining a healthy body weight, not smoking or drinking, managing stress, being active, and following a healthy diet are all things we can choose to do for a healthy life. Diet, as it turns out, may be the most important risk factor. The foods we choose to eat can help us prevent, treat, and even reverse high blood pressure. This is something I can proudly say I’ve done myself.
In my early to mid-twenties, I had prehypertension. When checked, my blood pressure was typically around 135/85 mmHg. I was young, slim, and active, so it was often dismissed as “white coat hypertension” caused by the anxiety of being in a doctor’s office. Yet, I would have it checked at work or at home, and it was still in the prehypertension range. Being in college for part of this time, I blamed it on my alcohol consumption. Looking back though, I was also consuming the typical American diet, which likely played a role as well. Flash forward to 2017, and my last blood pressure measurement was 105/75 mmHg (which it has consistently been over the past couple of years). What did I do to reverse my prehypertension? I changed my diet based on what the scientific literature indicated was the best approach. Here’s what I did, and what you should do too if you’re looking to improve your blood pressure.
Eat Less Sodium
Table salt is 40% sodium and 60% chloride. Although sodium is the nutrient of concern, I tend to use “sodium” and “salt” interchangeably. It is well established that eating salt raises our blood pressure in a dose-dependent manner (although the effect can vary from person to person). We have studies going back decades that clearly show adding salt to our diet increases blood pressure, while restricting salt lowers it (4-6). This is true over the long-term and the short-term, as a single salty meal can significantly increase one’s blood pressure for the next couple of hours (7). Although humans only need about 200-500 mg of sodium per day (which we can get naturally through whole foods), most Americans consume ten times this amount. When it comes to salt, less is better. The main sources of salt in our diet come from processed food and restaurant food. Eating more unprocessed food and preparing more meals at home is the best way to reduce your sodium intake. Over time, your taste preferences and blood pressure will acclimate to your new low-sodium diet.
Eat More Potassium
If blood pressure were an action film, sodium would be the villain and potassium would be the hero. Eating more high-potassium foods can lower blood pressure, especially in people who already have high blood pressure or who are eating a high-sodium diet (8-9). Foods rich in potassium include: all types of potatoes, tomatoes, all types of beans, all types of dark, leafy greens, pistachios, and avocados. Most plant foods contain a fair amount of potassium, which brings me to my next point.
Eat A Plant-Based Diet
There is an overwhelming and consistent amount of evidence showing that people eating vegetarian or vegan have lower rates of high blood pressure compared to their non-veg counterparts (10-12). In fact, it appears that the more “plant-based” someone eats, the lower their blood pressure. Studies of Seventh Day Adventists (who often consume a vegetarian or vegan diet for religious reasons) indicate that compared to omnivores, vegetarians have a 55% lower risk for high blood pressure, while vegans have a 75% lower risk (even after controlling for age, BMI, physical activity, and other potential confounding factors) (13). Given this data, one of the best ways to lower your risk for high blood pressure is to adopt a low-sodium, high-potassium, plant-based diet.
Try Adding These Foods To Your Diet
If you adopt a low-sodium, high-potassium, plant-based diet, your blood pressure will likely drop faster than an anvil on Wile E. Coyote. There are, however, some specific foods that appear capable of lowering our blood pressure on their own. Look to include these foods into your low-sodium, high-potassium, plant-based diet.
- Hibiscus Tea: Hibiscus tea has been used as a traditional remedy for high blood pressure throughout the world. This ancient wisdom now has some peer-reviewed data to back it up. One study found that drinking three cups of hibiscus tea daily for six weeks significantly reduced blood pressure, compared to drinking a placebo beverage (14). Other studies have shown that hibiscus tea can be just as effective at lowering blood pressure as blood pressure lowering medications, but with no negative side effects (15-16).
- High-Nitrate Plants: Nitrates can help lower blood pressure. You may have heard Viagra commercials state, “tell your doctor if you’re taking nitrates for chest pain, as this can cause an unsafe drop in blood pressure”. This is because nitrates can be converted into nitric oxide in our body, a gas that helps keep our blood vessels healthy. This, in turn, can lower blood pressure. There has been a recent spurt of studies looking at the blood pressure lowering potential of dietary nitrates and the majority of them show that dietary nitrates can indeed reduce blood pressure (17-22). Foods especially rich in nitrates include: arugula (rocket), spinach, lettuce, radishes, and beets (also beetroot juice).
- Ground Flaxseeds: Flaxseeds are healthy for a number of reasons. They are rich in omega-3 fat, fiber, and lignans (which may protect against breast and prostate cancer). They also appear capable of helping lower our blood pressure. One study found that eating three tablespoons worth of ground flaxseed daily for six months dropped participants systolic and diastolic blood pressure by 10 and 7 points, respectively, compared to a placebo. Researchers concluded, “flaxseed induced one of the most potent antihypertensive effects achieved by a dietary intervention.” In other words, they worked, really well. Flaxseed is best consumed ground (whole seeds tend to go right through us). I add it to my oatmeal, smoothies, or use a flax egg (1 tbsp ground flax mixed in 3 tbsp water; let sit for 5 minutes) as an egg replacement when baking.
Two-thirds of Americans suffer from hypertension or prehypertension. It’s a major risk factor for stroke, heart attacks, blindness, heart failure and kidney failure, yet it is largely preventable through a healthy diet and lifestyle. To prevent, treat, or reverse high blood pressure, maintain a healthy body weight, avoid smoking and drinking, manage stress, stay active, and consume a plant-based diet low in sodium and high in potassium. Make an extra effort to consume hibiscus tea, arugula, spinach, lettuce, radishes, beets, and ground flaxseed.
I should point out, that if you’re on medication to lower your blood pressure and plan to make these changes above (which I would encourage), inform your physician, as the combination may work too well and drop your blood pressure too low. The good news is, if you continue these healthy changes, you’ll likely be able to reduce or stop your medication all together!
- A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010.
- CDC High Blood Pressure Facts
- Intersalt:an international study of electrolyte excretion and blood pressure. Results for 24 hour urinary sodium and potassium excretion
- Double-blind randomised crossover trial of moderate sodium restriction in essential hypertension.
- Double-blind study of three sodium intakes and long-term effects of sodium restriction in essential hypertension.
- Effect of longer term modest salt reduction on blood pressure: Cochrane systematic review and meta-analysis of randomised trials.
- Dietary salt influences postprandial plasma sodium concentration and systolic blood pressure.
- Effects of Oral Potassium on Blood PressureMeta-analysis of Randomized Controlled Clinical Trials
- Daily potassium intake and sodium-to-potassium ratio in the reduction of blood pressure: a meta-analysis of randomized controlled trials
- Dietary Approaches to Prevent and Treat Hypertension: A Scientific Statement From the American Heart Association
- Low blood pressure in vegetarians: effects of specific foods and nutrients.
- Vegetarian Diets and Blood PressureA Meta-analysis
- Beyond Meatless, the Health Effects of Vegan Diets: Findings from the Adventist Cohorts
- Hibiscus Sabdariffa L. Tea (Tisane) Lowers Blood Pressure in Prehypertensive and Mildly Hypertensive Adults
- Effectiveness and tolerability of a standardized extract from Hibiscus sabdariffa in patients with mild to moderate hypertension: a controlled and randomized clinical trial.
- Clinical effects produced by a standardized herbal medicinal product of Hibiscus sabdariffa on patients with hypertension. A randomized, double-blind, lisinopril-controlled clinical trial.
- Vascular effects of dietary nitrate (as found in green leafy vegetables and beetroot) via the nitrate‐nitrite‐nitric oxide pathway
- Effects of Dietary Nitrate on Blood Pressure in Healthy Volunteers
- Dietary nitrate provides sustained blood pressure lowering in hypertensive patients: a randomized, phase 2, double-blind, placebo-controlled study
- Beetroot supplementation lowers daily systolic blood pressure in older, overweight subjects.
- High-nitrate vegetable diet increases plasma nitrate and nitrite concentrations and reduces blood pressure in healthy women.
- Effects of a nitrate-rich meal on arterial stiffness and blood pressure in healthy volunteers.
- Potent antihypertensive action of dietary flaxseed in hypertensive patients.