Abstract
Several randomized controlled trials have reported the effects of vegetarian diets on blood lipids and glucose homeostasis in adults, but not in overweight or obese individuals. Thus, the purpose of this study was to evaluate the effects of vegetarian diets on blood lipids and glucose homeostasis in overweight or obese adults by systematic review and meta-analysis. We searched Medline, Embase, and the Cochrane Library through October 2021. We chose to include overweight or obese patients in the studies of the vegetarian diet for metabolic control. Seven trials with a total of 783 overweight or obese adult were included in the meta-analysis. The analysis of the data revealed that the vegetarian diets significantly reduced low-density lipoprotein cholesterol (LDL-C) (WMD, −0.31; 95% CI, −0.46 to −0.16), total cholesterol (TC) (WMD, −0.37; 95% CI, −0.52 to −0.22), and HbA1c (WMD (%), −0.33; 95% CI, −0.55 to −0.11). The vegetarian diets had an elevated effect on blood triglycerides (WMD, 0.29; 95% CI, 0.11–0.47). However, there were no significant effects of vegetarian diets on high-density lipoprotein cholesterol (HDLC), Fasting plasma glucose(FPG), and HOMA-IR in these individuals. The results of this study suggest that vegetarian diets effectively reduce LDL-C, TC, and HbA1c levels, thus functioning as a promising therapeutic strategy for improving the metabolic dysfunction in overweight or obese individuals. However, further large-scale clinical trials are required to confirm the validity of these findings.
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Data availability
Data reviewed and analyzed during this meta-analysis is available from the corresponding author upon reasonable request.
References
Chooi YC, Ding C, Magkos F. The epidemiology of obesity. Metabolism. 2019;92:6–10.
Jaacks LM, Vandevijvere S, Pan A, McGowan CJ, Wallace C, Imamura F, et al. The obesity transition: stages of the global epidemic. Lancet Diabetes Endocrinol. 2019;7:231–40.
Afshin A, Forouzanfar MH, Reitsma MB, Sur P, Estep K, Lee A, et al. Health effects of overweight and obesity in 195 countries over 25 years. N Engl J Med. 2017;377:13–27.
Blüher M. Obesity: global epidemiology and pathogenesis. Nat Rev Endocrinol. 2019;15:288–98.
Jensen MD, Ryan DH, Apovian CM, Ard JD, Comuzzie AG, Donato KA, et al. 2013 AHA/ACC/TOS guideline for the management of overweight and obesity in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and The Obesity Society. Circulation. 2014;129 25 Suppl 2:S102–138.
Yumuk V, Tsigos C, Fried M, Schindler K, Busetto L, Micic D, et al. European guidelines for obesity management in adults. Obes Facts. 2015;8:402–24.
Najjar RS, Feresin RG. Plant-based diets in the reduction of body fat: physiological effects and biochemical insights. Nutrients. 2019;11:2712.
Huang RY, Huang CC, Hu FB, Chavarro JE. Vegetarian diets and weight reduction: a meta-analysis of randomized controlled trials. J Gen Intern Med. 2016;31:109–16.
Dinu M, Colombini B, Pagliai G, Giangrandi I, Cesari F, Gori A, et al. Effects of vegetarian versus Mediterranean diet on kidney function: findings from the CARDIVEG study. Eur J Clin Investig. 2021;51:e13576.
Kahleova H, Levin S, Barnard ND. Vegetarian dietary patterns and cardiovascular disease. Prog Cardiovasc Dis. 2018;61:54–61.
Olfert MD, Wattick RA. Vegetarian diets and the risk of diabetes. Current Diabetes Rep. 2018;18:101.
Agrawal S, Millett CJ, Dhillon PK, Subramanian SV, Ebrahim S. Type of vegetarian diet, obesity and diabetes in adult Indian population. Nutr J. 2014;13:89.
Appleby PN, Key TJ. The long-term health of vegetarians and vegans. Proc Nutr Soc. 2016;75:287–93.
Fresán U, Sabaté J. Vegetarian diets: planetary health and its alignment with human health. Adv Nutr. 2019;10 Suppl_4:S380–s388.
Obersby D, Chappell DC, Dunnett A, Tsiami AA. Plasma total homocysteine status of vegetarians compared with omnivores: a systematic review and meta-analysis. Br J Nutr. 2013;109:785–94.
Melina V, Craig W, Levin S. Position of the academy of nutrition and dietetics: vegetarian diets. J Acad Nutr Diet. 2016;116:1970–80.
Moher D, Liberati A, Tetzlaff J, Altman DG. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009;6:e1000097.
Moher D, Liberati A, Tetzlaff J, Altman DG. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. BMJ. 2009;339:b2535.
Luo D, Wan X, Liu J, Tong T. Optimally estimating the sample mean from the sample size, median, mid-range, and/or mid-quartile range. Stat Methods Med Res. 2018;27:1785–805.
Wan X, Wang W, Liu J, Tong T. Estimating the sample mean and standard deviation from the sample size, median, range and/or interquartile range. BMC Med Res Methodol. 2014;14:135.
Higgins JP, Thompson SG, Deeks JJ, Altman DG. Measuring inconsistency in meta-analyses. BMJ. 2003;327:557–60.
Chao AM, Quigley KM, Wadden TA. Dietary interventions for obesity: clinical and mechanistic findings. J Clin Investig. 2021;131:e140065.
Acharya SD, Brooks MM, Evans RW, Linkov F, Burke LE. Weight loss is more important than the diet type in improving adiponectin levels among overweight/obese adults. J Am Coll Nutr. 2013;32:264–71.
Barnard ND, Alwarith J, Rembert E, Brandon L, Nguyen M, Goergen A, et al. A mediterranean diet and low-fat vegan diet to improve body weight and cardiometabolic risk factors: a randomized, cross-over trial. J Am Nutr Assoc. 2022;41:127–39.
Barnard ND, Scialli AR, Turner-McGrievy G, Lanou AJ, Glass J. The effects of a low-fat, plant-based dietary intervention on body weight, metabolism, and insulin sensitivity. Am J Med. 2005;118:991–7.
Kahleova H, Petersen KF, Shulman GI, Alwarith J, Rembert E, Tura A, et al. Effect of a low-fat vegan diet on body weight, insulin sensitivity, postprandial metabolism, and intramyocellular and hepatocellular lipid levels in overweight adults: a randomized clinical trial. JAMA Netw Open. 2020;3:e2025454.
Neacsu M, Fyfe C, Horgan G, Johnstone AM. Appetite control and biomarkers of satiety with vegetarian (soy) and meat-based high-protein diets for weight loss in obese men: a randomized crossover trial. Am J Clin Nutr. 2014;100:548–58.
Sofi F, Dinu M, Pagliai G, Cesari F, Gori AM, Sereni A, et al. Low-calorie vegetarian versus mediterranean diets for reducing body weight and improving cardiovascular risk profile: CARDIVEG study (Cardiovascular Prevention With Vegetarian Diet). Circulation. 2018;137:1103–13.
Wright N, Wilson L, Smith M, Duncan B, McHugh P. The BROAD study: a randomised controlled trial using a whole food plant-based diet in the community for obesity, ischaemic heart disease or diabetes. Nutr Diabetes. 2017;7:e256.
Viguiliouk E, Kendall CW, Kahleová H, Rahelić D, Salas-Salvadó J, Choo VL, et al. Effect of vegetarian dietary patterns on cardiometabolic risk factors in diabetes: a systematic review and meta-analysis of randomized controlled trials. Clin Nutr. 2019;38:1133–45.
Wang F, Zheng J, Yang B, Jiang J, Fu Y, Li D. Effects of vegetarian diets on blood lipids: a systematic review and meta-analysis of randomized controlled trials. J Am Heart Assoc. 2015;4:e002408.
Barazzoni R, Gortan Cappellari G, Ragni M, Nisoli E. Insulin resistance in obesity: an overview of fundamental alterations. Eat Weight Disord. 2018;23:149–57.
Vekic J, Zeljkovic A, Stefanovic A, Jelic-Ivanovic Z, Spasojevic-Kalimanovska V. Obesity and dyslipidemia. Metabolism. 2019;92:71–81.
Borén J, Chapman MJ, Krauss RM, Packard CJ, Bentzon JF, Binder CJ, et al. Low-density lipoproteins cause atherosclerotic cardiovascular disease: pathophysiological, genetic, and therapeutic insights: a consensus statement from the European Atherosclerosis Society Consensus Panel. Eur Heart J. 2020;41:2313–30.
Mach F, Baigent C, Catapano AL, Koskinas KC, Casula M, Badimon L, et al. 2019 ESC/EAS Guidelines for the management of dyslipidaemias: lipid modification to reduce cardiovascular risk. Eur Heart J. 2020;41:111–88.
Jacobs DR Jr, Steffen LM. Nutrients, foods, and dietary patterns as exposures in research: a framework for food synergy. Am J Clin Nutr. 2003;78 3 Suppl:508s–513s.
Liu RH. Dietary bioactive compounds and their health implications. J Food Sci. 2013;78 Suppl 1:A18–25.
Fatahi S, Kord-Varkaneh H, Talaei S, Mardali F, Rahmani J, Ghaedi E, et al. Impact of phytosterol supplementation on plasma lipoprotein(a) and free fatty acid (FFA) concentrations: a systematic review and meta-analysis of randomized controlled trials. Nutr Metab Cardiovasc Dis. 2019;29:1168–75.
Rathnayake KM, Weech M, Jackson KG, Lovegrove JA. Impact of the apolipoprotein E (epsilon) genotype on cardiometabolic risk markers and responsiveness to acute and chronic dietary fat manipulation. Nutrients. 2019;11:2044.
Ulven SM, Leder L, Elind E, Ottestad I, Christensen JJ, Telle-Hansen VH, et al. Exchanging a few commercial, regularly consumed food items with improved fat quality reduces total cholesterol and LDL-cholesterol: a double-blind, randomised controlled trial. Br J Nutr. 2016;116:1383–93.
Zock PL, Blom WA, Nettleton JA, Hornstra G. Progressing insights into the role of dietary fats in the prevention of cardiovascular disease. Curr Cardiol Rep. 2016;18:111.
Imamura F, Micha R, Wu JH, de Oliveira Otto MC, Otite FO, Abioye AI, et al. Effects of saturated fat, polyunsaturated fat, monounsaturated fat, and carbohydrate on glucose-insulin homeostasis: a systematic review and meta-analysis of randomised controlled feeding trials. PLoS Med. 2016;13:e1002087.
Salmerón J, Hu FB, Manson JE, Stampfer MJ, Colditz GA, Rimm EB, et al. Dietary fat intake and risk of type 2 diabetes in women. Am J Clin Nutr. 2001;73:1019–26.
Craig WJ. Nutrition concerns and health effects of vegetarian diets. Nutr Clin Pract. 2010;25:613–20.
Rizzo NS, Jaceldo-Siegl K, Sabate J, Fraser GE. Nutrient profiles of vegetarian and nonvegetarian dietary patterns. J Acad Nutr Diet. 2013;113:1610–9.
Hartley L, May MD, Loveman E, Colquitt JL, Rees K. Dietary fibre for the primary prevention of cardiovascular disease. Cochrane Database Syst Rev. 2016;2016:Cd011472.
Anderson JW, Baird P, Davis RH Jr., Ferreri S, Knudtson M, Koraym A, et al. Health benefits of dietary fiber. Nutr Rev. 2009;67:188–205.
Barber TM, Kabisch S, Pfeiffer AFH, Weickert MO. The health benefits of dietary fibre. Nutrients. 2020;12:3209.
Ghaedi E, Kord-Varkaneh H, Mohammadi H, Askarpour M, Miraghajani M. Phytosterol supplementation could improve atherogenic and anti-atherogenic apolipoproteins: a systematic review and dose-response meta-analysis of randomized controlled trials. J Am Coll Nutr. 2020;39:82–92.
Ras RT, Geleijnse JM, Trautwein EA. LDL-cholesterol-lowering effect of plant sterols and stanols across different dose ranges: a meta-analysis of randomised controlled studies. Br J Nutr. 2014;112:214–9.
Gylling H, Plat J, Turley S, Ginsberg HN, Ellegård L, Jessup W, et al. Plant sterols and plant stanols in the management of dyslipidaemia and prevention of cardiovascular disease. Atherosclerosis. 2014;232:346–60.
Astrup A. The role of dietary fat in the prevention and treatment of obesity. Efficacy and safety of low-fat diets. Int J Obes Relat Metab Disord. 2001;25 Suppl 1:S46–50.
Rolls BJ. Dietary energy density: applying behavioural science to weight management. Nutr Bull. 2017;42:246–53.
Arora SK, McFarlane SI. The case for low carbohydrate diets in diabetes management. Nutr Metab (Lond). 2005;2:16.
Parks EJ. Effect of dietary carbohydrate on triglyceride metabolism in humans. J Nutr. 2001;131:2772s–2774s.
Janssen M, Busch C, Rödiger M, Hamm U. Motives of consumers following a vegan diet and their attitudes towards animal agriculture. Appetite. 2016;105:643–51.
Springmann M, Clark MA, Rayner M, Scarborough P, Webb P. The global and regional costs of healthy and sustainable dietary patterns: a modelling study. Lancet Planet Health. 2021;5:e797–e807.
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YX and CL conceptualized and designed the research study, performed initial statistical analyses, drafted the manuscript, approved the final manuscript as submitted, had full access to all the data in the study, and took responsibility for the integrity of the data and the accuracy of the data analysis; YX developed and implemented the systematic review search strategy, generating the initial search results; YX and YY independently reviewed study titles, abstracts, and full texts to determine included studies, performed data extraction, and evaluated each study for risk of bias; and YY and GLM assisted in refining the study design, reviewed and revised the manuscript, and approved the final manuscript as submitted.
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Xu, Y., Mo, G., Yao, Y. et al. The effects of vegetarian diets on glycemia and lipid parameters in adult patients with overweight and obesity: a systematic review and meta-analysis. Eur J Clin Nutr 77, 794–802 (2023). https://doi.org/10.1038/s41430-023-01283-x
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DOI: https://doi.org/10.1038/s41430-023-01283-x