Vegetarian diets do lower blood pressure, according to a new Japanese research study reported in the February issue of JAMA Internal Medicine. The landmark study, which involved more than 21,000 participants, is the first scientifically rigorous examination of the widely held belief that a vegetarian diet has real health benefits, confirming what mothers have known for hundreds of years about the importance of eating vegetables.
Proponents of vegetarian diets have encouraged their adoption for various health benefits including the reduction of bad cholesterol, improved weight control, and lowered risk of certain cancers. This is the first study to provide proof of a specific health benefit with respect to lowering blood pressure.
Participants in the study saw a drop of 6.9 mm of Mercury (Hg) in the systolic blood pressure and 4.7 mm of Hg in the diastolic blood pressure in an observational study of 21,604 participants. In seven separate clinical trials, 311 patients achieved a 4.8 mm Hg drop in the systolic rate and 2.2 mm Hg reduction in the diastolic blood pressure.
Averaged out between the two studies, participants improved their systolic rates by 5.8 mm Hg and lowered their diastolic rates by an average of 3.45 mm Hg.That is approximately half of the improvement in blood pressure gained from standard doses of typical blood pressure medications, and about the same improvement gained from lifestyle changes such as weight reduction, increased exercise regimens or reductions in salt use.
Based upon historical and epidemiological data, these numbers suggest that the adoption of a vegetarian diet could result in a 7 percent reduction in overall mortality, a 9 percent reduction in coronary heart disease, and 14 percent reduction in stroke rates.
The study’s authors suggest that the results could be related to the lower obesity rates and lower body mass indexes among vegetarians. Vegetarians also tend to use less salt and vegetarian diets are naturally high in potassium, known to reduce the negative effects of sodium in the body. The authors also suggested that vegetarians, being more health conscious, are less likely to use alcohol, tobacco or caffeine, all of which are known to drive up blood pressure levels. In addition to the direct health benefits, advocates of a vegetarian diet maintain that a meat-free diet reduces the strain on the environment caused by raising farm animals, and is more economical than a mixed diet because fruits and vegetables cost less than meat.
The methodology used in the studies incorporated a number of different types of vegetarian diets, including those that allow the use of fish, eggs, and milk products in the menu plans. Since the study was conducted in Japan, participants probably consumed larger portions of soy based food products, which contain larger than normal percentages of nutrients called isoflavones, which are believed to help lower blood pressure.
Some questions have been raised about the objectivity of the report because two of the researchers involved in the study are affiliated with the Physicians Committee for Responsible Medicine, a group that advocates plant-based diets. The statistical finding in the report have not been challenged, however.
Now that there is hard evidence supporting the value of vegetarian diets to blood pressure reduction programs, it may be easier for some people to rethink their dietary choices and reduce, if not eliminate, their dependency on animal protein. And mothers around the world now proof that they were right all along when they told their children to eat their vegetables.
By Alan M. Milner