Plant-based diets with small amounts meat and dairy may lower blood pressure, study finds

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Consuming a plant-based diet can lower blood pressure even if small amounts of meat and dairy are consumed too, according to new research from the University of Warwick and published in the Journal of Hypertension.

Plant-based diets support high consumption of fruits, vegetables, whole grains, legumes, nuts, and seeds, limiting the consumption of most or all animal products, mainly meat and dairy.

The researchers conducted a systematic review of previous research from controlled clinical trials to compare seven plant-based diets, several of which included animal products in small amounts, to a standardized control diet and the impact that these had on blood pressure. The researchers reviewed 41 studies involving 8,416 participants, in which the effects of seven different plant-based diets, including DASH, Mediterranean, vegetarian, vegan, Nordic, high fiber, and high fruit and vegetables, on blood pressure were studied in controlled clinical trials.

The review showed that most of these diets lowered blood pressure. The DASH diet had the largest effect reducing blood pressure by 5.53/3.79 mmHg compared to a control diet, and by 8.74/6.05 mmHg when compared to a “typical” control diet. A blood pressure reduction of the scale caused by a higher consumption of plant-based diets, even with limited animal products would result in a 14 percent reduction in strokes, a 9% reduction in heart attacks and a 7 percent reduction in overall mortality, the researchers said.

High blood pressure is the leading risk factor globally for heart attacks, stroke, and other cardiovascular diseases. A reduction in blood pressure has important health benefits both for individuals and for populations, the researchers said. Unhealthy diets are responsible for more deaths and disabilities globally than tobacco use, high alcohol intake, drug use, and unsafe sex put together. An increased consumption of whole grains, vegetables, nuts and seeds, and fruit, as achieved in plant-based diets, could avert up to 1.7, 1.8, 2.5, and 4.9 million deaths globally, respectively, every year, according to previous research.

Vegetarian and vegan diets with complete absence of animal products are already known to lower blood pressure compared to omnivorous diets. Their feasibility and sustainability are, however, limited. It has not been known whether a complete absence of animal products is necessary in plant-based dietary patterns to achieve a significant beneficial effect on blood pressure.

The researchers argued that any effort to increase plant-based foods in the diet and limit animal products is likely to benefit blood pressure and reduce risk of heart attacks, strokes, and cardiovascular disease.

"This is a significant finding as it highlights that complete eradication of animal products is not necessary to produce reductions and improvements in blood pressure,” said Joshua Gibbs, lead author of the study. “Essentially, any shift towards a plant-based diet is a good one."