A new study finds that vegetarians have lower blood pressure and that a vegetarian diet ranked as superior in reducing the risk of high blood pressure.

According to Reuters, scientists in the United States and Japan conducted a "meta-analysis" of 39 high-quality, studies from 18 countries. The studies involved more than 21,000 participants. The researchers found that people who avoid meat had lower blood pressure levels.

"Consumption of vegetarian diets is associated with lower [blood pressure]," the study's conclusion read. "Such diets could be a useful nonpharmacologic means for reducing [blood pressure]."

High blood pressure can increase a person's risk of heart disease, stroke, kidney disorders and other health problems. Victims usually are prescribed medication as a form of treatment. However, the cost of medication and the possible side effects can be issues.

A vegetarian diet excludes individuals from eating meat, but may include dairy products and eggs. The diet places an emphasis on food that includes vegetables, grains, legumes and fruits.

"If a diet change can prevent blood pressure problems or can reduce blood pressure, it would give hope to many people," Yoko Yokoyama, lead author told Reuters Health in an email. "However, in order to make healthful food choices, people need guidance from scientific studies. Our analysis found that vegetarian diets lower blood pressure very effectively, and the evidence for this is now quite conclusive."

According to the American Heart Association, blood pressure readings under 120 mm Hg systolic and 80 mm Hg diastolic (120/80) are considered normal. Clinical hypertension pressure starts at 140/90.

Research found that those who had a consistent vegetarian diet had an average systolic blood pressure of about 7 mm Hg lower, and a diastolic blood pressure that was 5 mm Hg lower, "than blood pressure readings of those who regularly ate meat and meat products."

"I would encourage physicians to prescribe plant-based diets as a matter of routine, and to rely on medications only when diet changes do not do the job," Yokoyama said. "And I would encourage everyone to try a plant-based diet, and especially to introduce plant-based diets to their children - they could prevent many health problems."

The results appeared in the journal JAMA Internal Medicine on Monday.