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  Can eating a vegetarian diet lower blood pressure? Both this review and other reviews of studies say YES, that those following vegetarian diets have a lower prevalence of hypertension. Overall, the mean prevalence of hypertension was 21% in those consuming a vegetarian diet and 29% in those consuming a nonvegetarian diet (the differences varied between studies).Those following a vegetarian diet also tended to have a healthier lifestyle. As the researchers point out: blood pressure medicine lowers blood pressure for one day, while lifestyle changes (diet, exercise, not smoking, limiting or avoiding alcohol) can lower blood pressure for life. From Medscape:

Vegetarian Diet: A Prescription for High Blood Pressure?

Hypertension is one of the most costly and poorly treated medical conditions in the United States and around the world. Consequences of hypertension include morbidity and mortality related to its long-term effects, which include stroke, myocardial infarction, renal failure, limb loss, aortic aneurysm, and atrial fibrillation, among many others. Although there is an armamentarium of medications to treat hypertension, we do little for prevention. In this review we examine the relationship between vegetarian and nonvegetarian diets and the prevalence of hypertension. 

Current nonpharmacologic treatments include: physical activity (≥ 30 minutes of moderate-intensity activity on most days of the week); smoking cessation; dietary modification (lower sodium, increased potassium; mainly plant-based foods; low-fat foods; reduced-fat dairy products; moderate amounts of lean unprocessed meats, poultry, and fish; and moderate amounts of polyunsaturated and monounsaturated fats, such as olive oil); weight reduction; management of stress; and limited alcohol consumption.

It is well known that hypertension is modulated by dietary influences. In this review we examine vegetarian, vegan, and nonvegetarian (omnivore) diets and prevalence of hypertension among these dietary populations. A vegetarian diet (ie, lacto/ovo-vegetarian) includes plant foods, dairy products, and eggs (excludes all meat, such as turkey, beef, poultry, seafood, bacon, etc.). A vegan diet is similar to vegetarian, except it further excludes dairy products and eggs (no animal or animal products). On the other hand, an omnivore diet (referred to as nonvegetarians throughout this study) includes both plant and animal foods and products.....The majority of studies included in this review addressed vegetarians and vegans as a single group (vegetarians), whereas others differentiated them. Vegetarian diets are known to be low in saturated fat and cholesterol, high in fiber, low in sodium, and high in potassium. These key elements have been shown to correlate with lower incidence of cancer, heart disease, and other chronic diseases, such as diabetes type II, hypertension, and hyperlipidemia.

The exact percentage of those following a vegetarian or vegan diet in the US is unknown; however, a 2014 study found that 221 of 11,399 adult respondents, from a group generally representing the demographics of the US, identified as vegan (0.5%), vegetarians (1.5%), or meat-eaters (98%). The prevalence of hypertension in the US in 2011 was roughly 33.8%.

The mean prevalence of hypertension in those consuming a vegetarian diet was 21% and 29% in those consuming a nonvegetarian diet. The overall prevalence of hypertension among vegetarians was 33% lower than nonvegetarian diets. These data support the hypothesis of a decreased prevalence of hypertension in those maintaining a vegan or vegetarian diet versus a nonvegetarian diet, in cross-sectional, cohort, and case-control studies, and in those consuming a vegan or vegetarian diet according to an experimental dietary change. The blood pressure benefit is noted to disappear in those reverting back to a nonvegetarian diet. 

Overall, these findings support previous reviews and meta-analyses of vegetarian and nonvegetarian diets and blood pressure. A recent meta-analysis that identified 39 studies with 21,915 participants concluded vegetarian diets were associated with a drop in mean systolic (-5.9 mm Hg) and diastolic (-3.5 mm Hg) blood pressures when compared with nonvegetarians. Other reviews had similar conclusions, showing that vegetarians have a lower blood pressure compared with nonvegetarians. Of the studies that included a vegan diet separate from other vegetarians (eg, lacto/ovo), the data show a significantly lower prevalence of hypertension when compared with nonvegetarians and other vegetarians. However, limited research has been conducted on strict, consistent vegan diets.

There are possible rationalizations for the observed associations between diet and hypertension. First, vegetarians have a lower rate of smoking tobacco. Smoking can increase blood pressure acutely and chronically over time.....Second, vegetarians tend to drink less alcohol compared with nonvegetarians. Alcohol, specifically ≥ 2 drinks/day, increases blood pressure by causing vasodilation, followed by a compensatory increase in blood pressure.....Further, vegetarians have a lower mean BMI when compared with nonvegetarians, which means a lower overall weight....Fourth, vegetarians tend to exercise more than nonvegetarians. Vegetarians reported a greater incidence of physical activity of ≥ 30 minutes of moderate to vigorous activity per day.

A limitation of this study is that it remains unclear whether vegetarians are more health conscious and therefore live healthier lives, or whether a predominant diet of fruits and vegetables is a basis for lower blood pressure.

photograph People are correctly raising the issue of whether the positive results (less diabetic nerve pain in type 2 diabetics) are due to the weight loss or to the vegan diet (which caused the quick weight loss)? I suspect it's the average 15 pound weight loss, which lowers inflammation and improves blood flow to the feet. And substituting whole plant-based foods (fruits, vegetables, whole grains, etc) for unhealthy highly processed foods has many health benefits, including controlling blood sugar. They all took B12 supplements because: B12 is found naturally only in animal products, so it's lacking in vegan diets; the diabetic medicine metformin lowers B12 levels; and a deficiency in vitamin B12 can actually cause nerve damage. Bottom line which applies to both diabetics and non-diabetics: some weight loss is good (if overweight), as is increasing beans, nuts, whole grains, vegetables, fruit and plant-based oils in the diet. From Medical Xpress:

Vegan diet might ease diabetic nerve pain

A vegan diet might help people with diabetes-related nerve damage shed weight and find some pain relief, a small pilot study suggestsVegan diets are free of all animal products, including eggs and dairy. Instead, people get their protein, fat and all other nutrients from foods such as beans, nuts, whole grains, vegetables, fruit and plant-based oils.

In the new study, researchers tested whether a vegan diet could help people with type 2 diabetes and painful nerve damage in their feet or hands. The investigators found that over 20 weeks, the 17 people they assigned to the diet lost an average of 15 pounds. At the same time, blood flow to their feet improved and their pain eased up.

But it's not clear that you have to go vegan to do that. "It's hard to say that it's this particular diet, itself," said Dr. Maria Pena, an endocrinologist and weight-management specialist at Lenox Hill Hospital in New York City. "The weight loss, by itself, can help with pain," said Pena, who was not involved in the study. Losing extra fat can decrease inflammation in the body, and improve a person's mobility—both of which could help ease diabetic nerve pain, she explained.

Plus, Pena said, better blood sugar control is key to reducing diabetic nerve pain—and the vegan dieters in this study did rein their sugar levels in. That shows the all-plant diet had benefits, according to Pena. But, she said, any diet that encourages weight loss and replaces processed foods with healthy "whole" foods might do the same.

About half of all people with diabetes eventually develop nerve damage because of chronically high blood sugar levels, according to the U.S. National Institutes of Health.The nerve damage—known as neuropathy—can occur anywhere, but most often affects the feet and legs. It can trigger sharp pain, burning sensations, tingling or sensitivity to even a light touch; it also makes people susceptible to serious foot problems, including ulcers and infections.

Cameron Wells, one of the researchers on the study, agreed that the finding doesn't prove that the vegan diet, per se, improved people's neuropathy. But the "hypothesis," she said, is that the diet worked by boosting people's sensitivity to the hormone insulin, which then brought down their blood sugar levels.

For the study, Wells and her colleagues recruited 34 adults with type 2 diabetes and painful neuropathy. They randomly assigned half to follow a vegan diet and take a vitamin B12 supplement; the rest took the supplement but stuck with their normal diets. The dieters were told to limit themselves to 20 to 30 grams of fat per day, and to load up on "low GI" foods, which are foods that do not cause a large surge in blood sugar.Breakfast might include oatmeal with raisins, Wells said, while dinner could be lentil stew, or a vegetable stir-fry with rice. After about five months, the vegan group had lost 15 pounds, on average, versus about 1 pound in the comparison group. They also reported bigger improvements on a standard pain-rating survey.

What was really interesting in the findings was not just that vegetarian diets are associated with an overall lower incidence of colorectal cancers, but that pescovegetarians (eat fish) had the lowest risk of all compared to nonvegetarians. That is really strong support for eating fish. From Science Daily:

Vegetarian diet linked to lower risk of colorectal cancers

Eating a vegetarian diet was associated with a lower risk of colorectal cancers compared with nonvegetarians in a study of Seventh-Day Adventist men and women, according to an article published online by JAMA Internal Medicine.

Colorectal cancer is the second leading cause of cancer death in the United States. Although great attention has been paid to screening, primary prevention through lowering risk factors remains an important objective. Dietary factors have been identified as a modifiable risk factor for colorectal cancer, including red meat which is linked to increased risk and food rich in dietary fiber which is linked to reduced risk, according to the study background.

Among 77,659 study participants, Michael J. Orlich, M.D., Ph.D., of Loma Linda University, California, and coauthors identified 380 cases of colon cancer and 110 cases of rectal cancer. Compared with nonvegetarians, vegetarians had a 22 percent lower risk for all colorectal cancers, 19 percent lower risk for colon cancer and 29 percent lower risk for rectal cancer. Compared with nonvegetarians, vegans had a 16 percent lower risk of colorectal cancer, 18 percent less for lacto-ovo (eat milk and eggs) vegetarians, 43 percent less in pescovegetarians (eat fish) and 8 percent less in semivegetarians, according to study results.

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I think many will say: Oh no! Totally vegan is best for weight loss?? From Science Daily:

Vegan diet best for weight loss even with carbohydrate consumption, study finds

People shed more weight on an entirely plant based diet, even if carbohydrates are also included, a study has concluded. Other benefits of eating a vegan diet include decreased levels of saturated and unsaturated fat, lower BMIs, and improved macro nutrients.

The study, conducted by the university's Arnold School of Public Health and published in The International Journal of Applied and Basic Nutritional Sciences, compared the amount of weight lost by those on vegan diets to those on a mostly plant-based diet, and those eating an omnivorous diet with a mix of animal products and plant based foods. At the end of six months, individuals on the vegan diet lost more weight than the other two groups by an average of 4.3%, or 16.5 pounds.

The study followed participants who were randomly assigned to one of five diets on the dietary spectrum: vegan which excludes all animal products, semi-vegetarian with occasional meat intake; pesco-vegetarian which excludes all meat except seafood; vegetarian which excludes all meat and seafood but includes animal products, and omnivorous, which excludes no foods.

Participants followed their assigned dietary restrictions for six months, with all groups except the omnivorous participating in weekly group meetings. Those who stuck to the vegan diet showed the greatest weight loss at the two and six month marks.The lead author on this study, Gabrielle Turner-McGrievy notes that the diet consumed by vegan participants was high in carbohydrates that rate low on the glycemic index