Inside: When I’m asked what foods help lower blood pressure, I explain that the strongest connection is in how foods come together in a mostly plant-based diet. Strategies to create such a diet are important for preventing and treating hypertension… including for people dealing with both high blood pressure and cancer.
The U.S. Surgeon General has issued an urgent call to action about the toll from uncontrolled high blood pressure. And helping people shape a heart-healthy diet that’s right for them has to be part of our response.
Quiz Question: Of the many potential strategies for a heart-healthy diet, if you had to pick which eating habits to change to reduce high blood pressure, which two or three are most important?
Actually, that question about best strategies is a trick question. – Research has identified multiple changes in eating habits that can reduce blood pressure and promote vascular health. Some seem to have a stronger influence than others. But picking which are most important for any individual needs to consider that individual’s starting point (which habits are furthest from recommendations). And you need to consider that healthy eating strategies may differ in effectiveness because of genetic and health differences, and factors that make some strategies an easier fit with lifestyle and personal preferences.
Let’s explore the research options for making choices about foods that help high blood pressure….
Call to Action on High Blood Pressure
Almost 1 in 2 US adults has hypertension, according to the latest statistics. Blood pressure is under control in only 1 in 4 of those people, with a decline seen between 2013 and 2018—well before all the challenges posed by COVID-19.
“I don’t want us to ever forget the tragedy of over 200,000 people who have died due to COVID-19…. but I also don’t want us to turn a blind eye to the more than 500,000 people who will die this year due to uncontrolled high blood pressure.” – U.S. Surgeon General Jerome M. Adams, MD, MPH
- In 2018, nearly half a million deaths in the United States included hypertension as a primary or contributing cause.
- Nearly half of adults in the United States (108 million, or 45%) have hypertension defined as a systolic blood pressure ≥130 mm Hg or a diastolic blood pressure ≥80 mm Hg or are taking medication for hypertension.
- Only about 1 in 4 adults (24%) with hypertension have their condition under control (defined as < 130/80). Less than half (44%) even reached under 140/90.
- Risk does not begin at a blood pressure of 140/90. That’s why current guidelines have eliminated the term “pre-hypertension” – blood pressures previously categorized that way are clearly not pre-risk.
In his call to action, Surgeon General Adams noted, “We know that two of the top things you can do to get your blood pressure under control are eating a healthy diet and being more active.”
What Foods Help Lower Blood Pressure?
When considering what to eat to lower blood pressure, we need to put well-established strategies like limiting sodium consumption in the context of wider research. For example, oxidative stress and chronic inflammation can create a vicious cycle, each increasing the other. Mounting evidence – from studies in older animals and in humans – shows that these may be major contributors to endothelial dysfunction and stiffening of large arteries, which in turn can increase blood pressure.
Make Vegetables and Fruits the Stars: Swapping proportions of food choices to give them the majority of the plate is important, but it’s only part of the goal. Aim for variety throughout the week, rather than focusing on a single “super food”. They provide minerals and phytochemicals that seem to act through several different pathways. Some may reduce blood pressure directly, other foods support vascular health, reducing harmful effects on blood pressure from artery stiffening.
Consider a sort-of checklist to see whether typical choice include:
- Potassium- and magnesium-rich choices, including citrus fruit and dark leafy greens
- Polyphenol-rich choices like berries, apples and grapes
- Nitrate-rich vegetables, like spinach, kale, beets and celery.
- Cruciferous vegetables like broccoli, cabbage and cauliflower
- Onion-family vegetables, providing allyl sulfur compounds
Some people ask whether or not fruit is really helpful, based on headlines that cast all foods with any sugar as bad choices. But lumping fruits with candy and cookies is inappropriate. Indeed, studies do show a modest but clinically significant difference for lower blood pressure linked with fruit consumption.
Reduce Sodium by Swapping Out Highly-Processed Foods: Many people think they’re well within recommendations to limit sodium because they don’t add much salt to their food. But it only takes a few food choices each day like canned soup, commercial pasta sauce, “seasoned” rice and other grain mixes and canned vegetables that are not labeled “No Added Salt” to send the daily total far over the top.
- If sodium is well beyond the recommended limit of 2300 mg/day, start with a realistic target. Even cutting 1000 mg/day can drop blood pressure by 2-4 /1-2 mm Hg.
- If concerns about flavor are the barrier, have fun exploring how herbs, spices, garlic, vinegar, lemon and other flavorings can give delicious food without counting on the salt shaker for all the flavor.
- For many people, excess sodium doesn’t come from a search for flavor, but convenience. They can often achieve the biggest drop in sodium by focusing on swapping out frequently-consumed processed foods for other choices. The key is exploring which choices they’ve been relying on as time-savers, and exploring alternative quick and easy options. A few doable tweaks can reach that target of dropping the daily sodium total by 1000 mg.
Choose Healthy Fats: Swapping unsaturated fats instead of foods high in saturated fat is a heart-healthy eating strategy grounded in reaching healthier levels of blood lipids. But emerging evidence suggests that fat-containing foods may affect blood pressure, too. Some evidence suggests that saturated fat may promote oxidative stress and inflammation.
- Nuts and unsaturated oils provide mono- and poly-unsaturated fats that promote healthy blood lipids. And they’re key elements of DASH diet modifications in the OmniHeart trial that reduced blood pressure even further than the original DASH diet. Extra virgin olive oil and nuts also provide polyphenols that could contribute to blood pressure control by reducing vascular aging.
- Including fish in a mostly plant-based diet at least twice a week might provide benefits beyond the reduction in saturated fat and sodium as a replacement for processed meats. So far research has not shown a direct link between seafood or the omega-3 fats it provides and blood pressure. But it’s possible that this reflects difficulty teasing out relationships looking separately at people who eat high-sodium convenience food or deep-fried fish from those who make healthier choices. Studies suggest that omega-3 fatty acids can improve endothelial function, especially in people who are at increased risk of heart disease, and that could play a role in better blood pressure.
Check Coffee, Tea and Caffeine Consumption: Research is unclear on what’s optimal for blood pressure. Coffee and tea (green tea and the more common black tea) contain polyphenol compounds that seem to support antioxidant defenses and promote vascular health.
- Coffee may not raise risk of developing high blood pressure, and may even provide some anti-inflammatory protection. But especially in amounts of three or more cups a day, it may make blood control more difficult for at least some people with existing hypertension.
- Tea may be a choice that can help fight hypertension, based on results of human intervention trials and animal studies. Credit likely goes to effects of tea’s polyphenol compounds increasing nitric oxide synthesis and reducing oxidative stress and vascular inflammation. Benefits aren’t consistent for everyone. So this is an optional strategy to consider, not an essential step, to consider on an individual basis.
- When caffeine comes from soft drinks, which lack the protective polyphenols found in tea and coffee and are laden with excess added sugar, this may show a more harmful blood pressure response in people sensitive to caffeine. Don’t group all sources of caffeine as equals.
How to Create a Mostly Plant-Based Diet for Better Blood Pressure
The focus for reaching and maintaining a healthy blood pressure, as with other aspects of health, comes down to creating eating habits that include more protective foods while reducing consumption of foods that raise blood pressure and promote vascular aging.
Studies show a variety of eating patterns that accomplish this, and it’s not clear that one is necessarily better than all others…. That’s especially important when you consider the goal of this eating pattern as something that fits an individual’s preferences and lifestyle so that it can become a long-term way of eating. Be cautious when you see headlines advocating any particular type of diet as “best”, because often the comparison in a study was to a typical Western (unhealthy) diet.
In short, there are lots of ways to eat for a better blood pressure.
- Vegetarian diets are what may come to mind when we’re talking about plant-based diets. And both completely plants-only diets and lacto-vegetarian diets are associated with better blood pressure. Pesco-vegetarian diets – plant-forward diets that include fish and seafood – also are good choices for blood pressure and cardiovascular health.
- The DASH diet, including modifications that don’t keep total fat low, has some of the strongest support as an eating pattern that both prevents hypertension and reduces blood pressure in people with hypertension. A key point to me are the findings that this overall dietary pattern can compensate to a degree when people have trouble reducing sodium to recommended levels, which includes so many people today.
- A Mediterranean diet can also help reduce or avoid high blood pressure, according to some studies. Exciting work shows potential for improving endothelial function and other aspects of cardiovascular health. But it’s important to clarify specific choices involved, since the concept of a Mediterranean diet may mean different things in different studies, and in different individuals’ perceptions.
When people ask about headlines related to low-carbohydrate diets, it’s important to dig deeper. Before assuming that reducing carbohydrate is the answer, look at what research shows about the importance of carbohydrate quality. Healthy portions are certainly helpful, and essential to reach and maintain a weight that supports a healthy blood pressure. But many of the foods noted above with protective nutrients and phytochemicals that combine to create a mostly plant-based diet supply carbohydrate (including dietary fiber).
Bottom Line on a Diet for Healthy Blood Pressure:
Amidst the current prevalence of hypertension, including among people already at cardiovascular risk because of other chronic disease or cardiotoxic cancer treatment, focus on creating eating habits for better blood pressure needs to be a priority. The good news is that there are many ways to bring foods together in a mostly plant-based diet that provide blood pressure protectors while reducing high-sodium foods that raise blood pressure. We need to explore strategies that surmount barriers for each individual.
Adams JM, Wright JS. A National Commitment to Improve the Care of Patients With Hypertension in the US. JAMA. Published online October 07, 2020. doi:10.1001/jama.2020.20356
US Department of Health & Human Services. Surgeon General’s Call to Action to Control Hypertension. Published October 7, 2020.
Photo credit (image used with permission):
Top image: Olga Yastremska – Copyright 123rf.com – 119839646_s