They found that giving up meat can lead to falls in blood pressure similar to losing 5kg in weight or going on a low-sodium diet.
"The diet achieves around half the drop expected from prescription drugs," reported the Mail Online.
In an email to Reuters Health, researcher Yoko Yokoyama who lead the team based in Osaka at the National Cerebral and Cardiovascular Center in Osaka, said: "High blood pressure contributes to a person's risk of heart disease, stroke, kidney disorders and other health problems. For many people, the only treatment has been medication, but that means costs and possible side effects.
"However, in order to make healthful food choices, people need guidance from scientific studies," she said. "Our analysis found that vegetarian diets lower blood pressure very effectively, and the evidence for this is now quite conclusive."
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The researchers looked at the findings of seven clinical trials - which included 311 participants - and 32 observational studies (looking at 21,604 participants).
A vegetarian diet was defined as excluding or rarely including meat, but including dairy products, eggs and fish.
WHAT IS BLOOD PRESSURE?
To find out your blood pressure, two measurements are recorded during a single heartbeat:
- the level of pressure when your heart pumps blood through your arteries and around your body (systolic pressure): this is when the pressure is highest, and
- the level of pressure when your heart is resting before it pumps again (diastolic pressure): this is when the pressure is lowest
Blood pressure is measured in millimetres of mercury (mmHg). The readings are given as two numbers or levels. The systolic reading is first, followed by the diastolic reading. For example, if your systolic reading is 120mmHg and your diastolic reading is 80mmHg, your blood pressure is 120 over 80. This is commonly written as 120/80.
Medical News Today reported: "The researchers measured the difference in millimeters of mercury (mm Hg) - the unit blood pressure is measured in - between participants who followed a vegetarian diet and participants who followed an omnivorous diet. In terms of systolic blood pressure (the pressure in the arteries when the heart beats), the researchers found that the blood pressure of vegetarians was 4.8 mm Hg lower overall than omnivores in clinical trials and 6.9 mm Hg lower in observational studies.
"In terms of diastolic blood pressure (the pressure in the arteries between heartbeats), the researchers found that the blood pressure of those following a vegetarian diet overall was 2.2 mm Hg lower in clinical trials and 4.7 mm Hg lower in observational studies."
"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 added. "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."
However - a vegetarian diet, as the Mail Online has rightly pointed out - still has plenty of room for error. It quoted Victoria Taylor, senior dietitian at the British Heart Foundation as saying: "...simply removing meat from the diet isn't a fast track to heart health - many foods high in saturated fat, salt and sugar will be vegetarian options too.
"Whether you eat meat or not, getting plenty of fruit and vegetables, eating less salt, maintaining a healthy weight and, if you drink alcohol, keeping within government recommendations are all important as part of the healthy and active lifestyle that will help to keep your blood pressure down."
The findings were published in the journal JAMA Internal Medicine.