, in a new meta-analysis of 30 trials.
The findings suggest that “plant-based diets have the potential to lessen the atherosclerotic burden from atherogenic lipoproteins and thereby reduce the risk of cardiovascular disease,” write Caroline Amelie Koch, a medical student at the University of Copenhagen, and colleagues. Their findings were published online in the European Heart Journal (2023 May 24. doi: 10.1093/eurheartj/ehad211).
“Vegetarian and vegan diets were associated with a 14% reduction in all artery-clogging lipoproteins as indicated by apoB,” senior author Ruth Frikke-Schmidt, DMSc, PhD, Rigshospitalet, Copenhagen, and professor, University of Copenhagen, said in a press release from her university.
“This corresponds to a third of the effect of taking cholesterol-lowering medications such as statins,” she added, “and would result in a 7% reduction in the risk of cardiovascular disease in someone who maintained a plant-based diet for 5 years.”
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“Importantly, we found similar results, across continents, ages, different ranges of body mass index, and among people in different states of health,” Dr. Frikke-Schmidt stressed.
And combining statins with plant-based diets would likely produce a synergistic effect, she speculated.
“If people start eating vegetarian or vegan diets from an early age,” she said, “the potential for reducing the risk of cardiovascular disease caused by blocked arteries is substantial.”
In addition, the researchers conclude: “Shifting to plant-based diets at a populational level will reduce emissions of greenhouse gases considerably – together making these diets efficient means [moving] towards a more sustainable development, while at the same time reducing the growing burden of atherosclerotic cardiovascular disease.”
More support for vegan, vegetarian diets
These new findings “add to the body of evidence supporting favorable effects of healthy vegan and vegetarian dietary patterns on circulating levels of LDL-C and atherogenic lipoproteins, which would be expected to reduce ASCVD risk,” Kevin C. Maki, PhD, and Carol Kirkpatrick, PhD, MPH, write in an accompanying editorial.
“While it is not necessary to entirely omit foods such as meat, poultry, and fish/seafood to follow a recommended dietary pattern, reducing consumption of such foods is a reasonable option for those who prefer to do so,” note Dr. Maki, of Indiana University School of Public Health, Bloomington, and Kirkpatrick, of Idaho State University, Pocatello.
Plant-based diet needs to be ‘well-planned’
Several experts who were not involved in this meta-analysis shed light on the study and its implications in comments to the U.K. Science Media Center.
“Although a vegetarian and vegan diet can be very healthy and beneficial with respect to cardiovascular risk, it is important that it is well planned so that nutrients it can be low in are included, including iron, iodine, vitamin B12, and vitamin D,” said Duane Mellor, PhD, a registered dietitian and senior lecturer, Aston Medical School, Aston University, Birmingham, England.
Some people “may find it easier to follow a Mediterranean-style diet that features plenty of fruit, vegetables, pulses, wholegrains, fish, eggs and low-fat dairy, with only small amounts of meat,” Tracy Parker, senior dietitian at the British Heart Foundation, London, suggested.
“There is considerable evidence that this type of diet can help lower your risk of developing heart and circulatory diseases by improving cholesterol and blood pressure levels, reducing inflammation, and controlling blood glucose levels,” she added.
And Aedin Cassidy, PhD, chair in nutrition & preventative medicine, Queen’s University Belfast (Ireland), noted that “not all plant-based diets are equal. Healthy plant-based diets, characterized by fruits, vegetables, and whole grains improve health, but other plant diets (for example, those including refined carbohydrates, processed foods high in fat/salt, etc.) do not.”
This new study shows that plant-based diets have the potential to improve health by improving blood lipids, “but this is one of many potential mechanisms, including impact on blood pressure, weight maintenance, and blood sugars,” she added.
“This work represents a well-conducted analysis of 30 clinical trials involving over two thousand participants and highlights the value of a vegetarian diet in reducing the risk of heart attack or stroke through reduction in blood cholesterol levels,” said Robert Storey, BM, DM, professor of cardiology, University of Sheffield, U.K.
However, it also demonstrates that the impact of diet on an individual’s cholesterol level is relatively limited, he added.
“This is because people inherit the tendency for their livers to produce too much cholesterol, meaning that high cholesterol is more strongly influenced by our genes than by our diet,” he explained.
This is “why statins are needed to block cholesterol production in people who are at higher risk of or have already suffered from a heart attack, stroke, or other illness related to cholesterol build-up in blood vessels.”