Plant-based diets can lower cholesterol and fat in the blood - reducing blocked arteries and lowering the risk of heart and blood vessel diseases, reveals a new study. Vegetarians and vegans saw their risk of cardiovascular disease drop by seven per cent over five years compared to ominivores.
But it was only a third of the effect of taking statins, though researchers said a plant-based diet combined with statins would boost the effect further. Researchers examined 30 randomised trials with just over 2,300 participants, published between 1982 and 2022.
The trials revealed how vegetarian and vegan diets effect all types of cholesterol compared to omnivorous diets, where people continue to eat meat and dairy. The first two types are low-density lipoprotein cholesterol (LDL), which is known as the bad cholesterol, and triglycerides, a type of fat found in the blood.
The third type is apoliprotein B (apopB), a protein that helps carry fat and cholesterol in blood and is a good indicator of the total amount of bad fats and cholesterol in the body. Thanks to the apoliprotein B, they found that vegetarian and vegan diets were linked with a 14 per cent drop in all artery-clogging lipoproteins.
Compared to people eating an omnivorous diet, vegetarians and vegans also saw a 10 per cent reduction in LDL cholesterol levels. Overall, they experienced an average drop in total cholesterol of seven per cent from when they started the study.
Study author, Professor Ruth Frikke-Schmidt, a chief physician at the Rigshospitalet in Copenhagen, Denmark, said: “We found that vegetarian and vegan diets were associated with a 14 per cent reduction in all artery-clogging lipoproteins as indicated by apoliprotein B. This corresponds to a third of the effect of taking cholesterol-lowering medications such as statins, and would result in a seven per cent reduction in the risk of cardiovascular disease in someone who maintained a plant-based diet for five years.
“Statin treatment is superior to plant-based diets in reducing fats and cholesterol levels. However, one regimen does not exclude the other, and combining statins with plant-based diets is likely to have a synergistic effect, resulting in an even larger beneficial effect.”
She added: “If people start eating vegetarian or vegan diets from an early age, the potential for reducing the risk of cardiovascular disease caused by blocked arteries is substantial. Importantly, we found similar results across continents, ages, different ranges of body mass index, and among people in different states of health.”
The participants were randomly picked to follow either a vegetarian or vegan diet or to continue eating meat and dairy. The length of time on the diets ranged from ten days to five years, with an average of 29 weeks.
Professor Frikke-Schmidt said: “We saw significant effects from both vegetarian and vegan diets and people ranging from a normal weight to obese.” Over 18 million people die from cardiovascular disease (CVD) each year around the world, making it the leading cause of death.
It is responsible for one in four premature deaths in the UK, with those from poorer areas being more likely to die from cardiovascular issues. These problems include coronary heart disease, angina, heart attack, high blood pressure and stroke.
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The United Nations’ Sustainable Development Agenda states that premature deaths from non-communicable diseases, like CVD, should be reduced by a third by 2030. They are also increasing their focus on the effect of what we eat on the environment.
Professor Frikke-Schmidt added: “Recent systematic reviews have shown that if the populations of high-income countries shift to plant-based diets, this can reduce net emissions of greenhouse gases by between 35 per cent to 49 per cent. Our study provides robust evidence that plant-based diets are good for our health for people of different sizes, ages and health conditions.
“Furthermore, populations globally are aging and, as a consequence, the cost of treating age-related diseases such as atherosclerotic cardiovascular disease is increasing. Plant-based diets are key instruments for changing food production to more environmentally sustainable forms, while at the same time reducing the burden of cardiovascular disease.
“We should be eating a varied, plant-rich diet, not too much, and quenching our thirst with water.” The study was not able to find out the potential benefits of a pescatarian diet as there were not enough studies available.
Professor Frikke-Schmidt said: “However, the Mediterranean diet is rich in plant-based foods and fish and is well-established as being beneficial in dietary guidelines.”
Professor Kevin Maki, from Indiana University School of Public Health Bloomington, US, who was not involved in the research, said: “The results reported by Koch et al add to the body of evidence supporting favourable effects of healthy vegan and vegetarian dietary patterns on circulating levels of LDL-C [LDL cholesterol] and atherogenic lipoproteins, which would be expected to reduce ASCVD [atherosclerotic CVD] risk.
“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.”
To the authors’ knowledge, this is the largest systematic review of the topic and is the first to include apoB. However, limitations include the fact that the trials were relatively small, the length of time participants were on diets was under a year in many studies, and it was impossible to blind the participants to which diet they were placed on.
It is possible these factors could have influenced their other behaviours and may have affected their cholesterol and fat levels. The study was published in the European Heart Journal.
