Vegan and Vegetarian Diets Associated with Reduced Apoliprotein B, Total Cholesterol and LDL-C Levels

by | Aug 8, 2023 | 2023, Blood Lipids, Cardiovascular Health, Vegetarianism

Written by Taylor Woosley, Staff Writer. A systematic review and meta-analysis of 30 RCTs focused on plant-based diets and cholesterol levels shows that subjects following a vegan or vegetarian diet had reduced levels of total cholesterol, lipoprotein cholesterol, and apolipoprotein B compared to participants following an omnivore diet. 

fruit and vegetablesCardiovascular disease (CVD) is the leading cause of death and disability worldwide1. CVD is a broad term associated with many different conditions of the cardiovascular system and includes myocardial infarction, heart failure, and stroke2. These conditions share several risk factors, such as obesity, diabetes, hypertension, hyperlipidemia, diet, and lifestyle3.

The potentially beneficial role of plant-based diets in cardiovascular health has been increasingly recognized, with accumulating evidence documenting their health effects4. Epidemiological studies have shown that vegetarian and vegan diets, primarily based on vegetables, legumes, fruit, grain, and nuts, is associated with a reduced incidence of cardiovascular disease5. Furthermore, the latest evidence suggests that subjects following a plant-based diet usually have reduced total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), and blood glucose levels compared to omnivores6.

Koch et al. conducted a systematic review and meta-analysis to analyze the effect of vegan and vegetarian diets on atherogenic lipoprotein B (apoB), the main apolipoprotein in LDL-C and TG-rich lipoproteins. Study inclusion consisted of studies with subjects aged ≥18 years, with an intervention focused on consumption of a vegan or vegetarian diet, with a comparison that was an omnivorous control group, with outcomes including blood, serum, or plasma levels of TC, LDL-C, TG, and/or apoB. Subgroup analyses were performed for TC, LDL-C, and TG by mean age at baseline, mean BMI at baseline, study location, duration of trial, health status, intervention diet, intervention program, sample size, and study design. Publication bias was assessed by analyzing funnel plots for each meta-analysis and Egger’s linear regression test was utilized to test for plot asymmetry.

30 randomized controlled trial (RCTs) were included in the final systematic review and meta-analysis. Study intervention ranged from 10 days to 5 years, with an average of 29 weeks. 9 studies used a crossover design and 21 followed a parallel design. Study sample size ranged from 11 to 291 subjects (mean=79), with a mean BMI between 21.5 and 35.1 kg/m2, and a mean age between 20 and 67 years. 5 studies focused solely on healthy participants and 25 studies focused on participants with a specific health condition (primarily CVD or type 2 diabetes). 15 studies had a vegetarian dietary intervention, and 15 studies followed a vegan dietary intervention. Significant findings of the systematic review and meta-analysis are as follows:

  • Subjects who followed a plant-based diet showed a mean reduction in TC of -0.34 mmol/L (95% CI: -0.44, -0.23; p = 1 x 10-9; I2=69.03%), equivalent to a 7% reduction from baseline compared to the omnivorous control group.
  • Mean reductions in LDL-C levels were -0.30 mmol/L in the plant-based group (-0.40, -0.19; p = 4 x 10-8; I2=73.67%) corresponding to a 10% reduction from baseline.
  • No changes were noted in TG levels (0.06 mmol/L; 7%; -0.01, 0.13; p = 0.11; I2=54.26).
  • ApoB meta-analysis findings show a decrease in apoB levels of -12.92 mg/dL (-22.63, -3.20; p = 0.01; I2=71.69%), resulting in a 14% reduction from baseline.

Results of the systematic review and meta-analysis suggest that participants following a plant-based diet experienced reduced TC, LDL-C, and apoB concentrations compared to subjects following an omnivore diet. Further research should continue to explore the potential cardiovascular benefits of adopting a plant-based diet. Study limitations include the small sample sizes of the RCTS and short study durations, the lack of participant blinding and the inability to assess randomization processes of each included study due to lack of relevant information.

Source: Koch, Caroline A., Emilie W. Kjeldsen, and Ruth Frikke-Schmidt. “Vegetarian or vegan diets and blood lipids: a meta-analysis of randomized trials.” European Heart Journal (2023): ehad211.

© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (https://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com

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Posted August 8, 2023.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

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