A systolic/diastolic blood pressure >140/90 mmHg constitutes a diagnosis of hypertension. Across the blood pressure range from 115/75 to 185/115 mm Hg, every incremental increase of 20 mm Hg in systolic or 10 mm Hg in diastolic blood pressure is associated with more than twice the risk of cardiovascular disease. Conversely, very modest reductions in blood pressure can lead to significant reductions in the risk of cardiovascular events. For example, as highlighted in the HOPE study, a 3 mmHg reduction in systolic blood pressure is associated with a 22% reduction in cardiovascular disease-related death, heart attack, or stroke over 4.5 years.
So how does one go about achieving a reduction in blood pressure?
Most experts suggest blood-pressure reducing medication along with lifestyle modification as the best method. Indeed, numerous studies suggest that modifiable lifestyle factors, including a diet high in salt, excess body weight, limited physical activity, and alcohol intake, all play a role in increasing the risk of developing hypertension. For some time, it has also been suggested that switching to a vegetarian diet can help reduce the stress on your arteries.
In a recent meta-analysis (study of many studies) published in JAMA Internal Medicine, Yokoyama and colleagues looked at 7 controlled trials and 32 observational studies to examine the influence of a vegetarian versus an omnivorous diet on blood pressure. Their analysis included a whopping total of 21915 subjects!
Across the controlled studies, where subjects were part of an intervention that included a change to a vegan or vegetarian diet, systolic and diastolic blood pressure was found to reduce by −4.8 mm Hg and −2.2 mm Hg, respectively, by comparison to the consumption of omnivorous diets.
Within the observational studies, where subjects were simply evaluated for diet composition as well as blood pressure, those who followed any form of a vegan or vegetarian diet (lacto, lacto-ovo, pesco, and/or semivegetarian) had on average a 6.9 mmHg lower mean systolic and 4.7 mmHg lower diastolic blood pressure, by comparison to those who consumed omnivorous diets.
The blood pressure reduction reported in response to a vegetarian diet are generally similar to those observed with other lifestyle modifications, such as a low-salt diet or a weight loss of 5 kg, and are approximately half the magnitude of those observed with blood-pressure lowering drugs. Keep in mind, however, that even a 3 mmHg reduction in systolic blood pressure is associated with a 22% reduction in cardiovascular disease-related death, heart attack, or stroke over 4.5 years. So while small in number, these changes in blood pressure associated with eating no or less animal products are clearly meaningful when it comes to your overall health.
Being raised by Eastern European parents, I find it hard to not include meat as part of most meals, so I’m not sure a full-on vegetarian diet is going to happen. However, I have made a conscious effort to reduce the amount of meat that I consume, and have really enjoyed the Meatless Monday approach. All small but maintainable steps in the right direction.