Consumption of plant-based diets, including vegan diets, necessitates attention to the quality of the diet for the prevention and early detection of nutritional deficiencies. Within the VEGANScreener project, a unique brief screening tool for the assessment and monitoring of diet quality among vegans in Europe was developed. To provide a standardized tool for public use, a clinical study will be conducted to evaluate the VEGANScreener against a reference dietary assessment method and nutritional biomarkers. An observational study is set to include 600 participants across five European sites - Belgium, Czech Republic, Germany, Spain, and Switzerland. In total, 400 self-reported vegans (≥2 years on a vegan diet), and 170 self-reported omnivore controls will be examined, aged between 18 and 65 years, with males and females being equally represented in a 1:1 ratio for two age groups (18-35 and 36-65 years). Participants with diseases affecting metabolism and intestinal integrity will be excluded. The clinical assessment will include a structured medical history, along with taking blood pressure and anthropometric measurements. Blood and urine will be sampled and analyzed for a set of dietary biomarkers. Metabolomic analyses will be conducted to explore potential novel biomarkers of vegan diet. Moreover, saliva samples will be collected to assess the metabolome and the microbiome. Participants will receive instructions to complete a nonconsecutive 4-day diet record, along with the VEGANScreener, a socio-demographic survey, a well-being survey, and a FFQ. To evaluate reproducibility, the VEGANScreener will be administered twice over a three-weeks period. Among vegans, the construct validity and criterion validity of the VEGANScreener will be analyzed through associations of the score with nutrient and food group intakes, diet quality scores assessed from the 4-day diet records, and associations with the dietary biomarkers. Secondary outcomes will include analysis of dietary data, metabolomics, and microbiomes in all participants. Major nutrient sources and variations will be assessed in the sample. Exploratory metabolomic analysis will be performed using multivariable statistics and regression analysis to identify novel biomarkers. Standard statistical models will be implemented for cross-sectional comparisons of geographical groups and vegans versus omnivores.

CIBERobn Instituto de Salud Carlos 3 Madrid Spain

Department Nutrition and Dietetics Faculty of Health Professions Bern University of Applied Sciences Bern Switzerland

Department of Epidemiology Center for Public Health Medical University of Vienna Vienna Austria

Department of Epidemiology Harvard T H Chan School of Public Health Boston MA United States

Department of Internal Medicine 3rd Faculty of Medicine Charles University and Kralovske Vinohrady University Hospital and 3rd Faculty of Medicine Charles University Prague Czechia

Department of Nutritional Sciences Faculty of Life Sciences University of Vienna Vienna Austria

Department of Preventive Medicine and Public Health University of Navarra IdiSNA Pamplona Spain

Department of Social and Preventive Medicine Center for Public Health Medical University of Vienna Vienna Austria

Faculty of Economics and Business Department of Public Health and Primary Care Ghent University Ghent Belgium

Faculty of Medicine and Health Sciences Department of Public Health and Primary Care Ghent University Ghent Belgium

HOGENT University of Applied Sciences and Arts Ghent Belgium

Institute for Clinical and Experimental Medicine Prague Czechia

Institute for Molecular Medicine Finland University of Helsinki Helsinki Finland

Institute of Microbiology of the CAS Prague Czechia

Laboratory of Nutrition and Metabolic Epigenetics Institute of Food Nutrition and Health ETH Zürich Zürich Switzerland

Research Institute for Plant Based Nutrition Biebertal Germany

See more in PubMed

Gheihman N. Veganism as a lifestyle movement. Soc Comp. (2021) 15:1–14. doi: 10.1111/soc4.12877 DOI

What does it mean to consumers? An exploration into diets around the world. (2018).

Oliver C. Vegan world-making in meat-centric society: the embodied geographies of veganism. Soc Cult Geogr. (2021) 24:831–50. doi: 10.1080/14649365.2021.1975164 DOI

Ghaffari M, Rodrigo PGK, Ekinci Y, Pino G. Consumers’ motivations for adopting a vegan diet: a mixed-methods approach. Int J Consum Stud. (2022) 46:1193–208. doi: 10.1111/ijcs.12752 DOI

Martinelli D, Berkmanienė A. The politics and the demographics of veganism: notes for a critical analysis. Int J Semiot Law. (2018) 31:501–30. doi: 10.1007/s11196-018-9543-3 DOI

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. doi: 10.1016/j.appet.2016.06.039 PubMed DOI

Neufingerl N, Eilander A. Nutrient intake and status in adults consuming plant-based diets compared to meat-eaters: A systematic review. Nutrients. (2022) 14. doi: 10.3390/nu14010029 PubMed DOI PMC

Bakaloudi DR, Halloran A, Rippin HL, Oikonomidou AC, Dardavesis TI, Williams J, et al. . Intake and adequacy of the vegan diet. A systematic review of the evidence. Clin Nutr. (2021) 40:3503–21. doi: 10.1016/j.clnu.2020.11.035 PubMed DOI

Parker HW, Vadiveloo MK. Diet quality of vegetarian diets compared with nonvegetarian diets: a systematic review. Nutr Rev. (2019) 77:144–60. doi: 10.1093/nutrit/nuy067, PMID: PubMed DOI

Selinger E, Neuenschwander M, Koller A, Gojda J, Kühn T, Schwingshackl L, et al. . Evidence of a vegan diet for health benefits and risks–an umbrella review of meta-analyses of observational and clinical studies. Crit Rev Food Sci Nutr. (2022) 63:9926–36. doi: 10.1080/10408398.2022.2075311 PubMed DOI

Pollakova D, Andreadi A, Pacifici F, Della-Morte D, Lauro D, Tubili C. The impact of vegan diet in the prevention and treatment of type 2 diabetes: a systematic review. Nutrients. (2021) 13:2123. doi: 10.3390/nu13062123, PMID: PubMed DOI PMC

Wang T, Masedunskas A, Willett WC, Fontana L. Vegetarian and vegan diets: benefits and drawbacks. Eur Heart J. (2023) 44:3423–39. doi: 10.1093/eurheartj/ehad436, PMID: PubMed DOI PMC

Wang Y, Liu B, Han H, Hu Y, Zhu L, Rimm EB, et al. . Associations between plant-based dietary patterns and risks of type 2 diabetes, cardiovascular disease, cancer, and mortality - a systematic review and meta-analysis. Nutr J. (2023) 22:46. doi: 10.1186/s12937-023-00877-2 PubMed DOI PMC

Crosby L, Rembert E, Levin S, Green A, Ali Z, Jardine M, et al. . Changes in food and nutrient intake and diet quality on a low-fat vegan diet are associated with changes in body weight, body composition, and insulin sensitivity in overweight adults: a randomized clinical trial. J Acad Nutr Diet. (2022) 122:1922–1939.e0. doi: 10.1016/j.jand.2022.04.008, PMID: PubMed DOI

Schmidt JA, Rinaldi S, Ferrari P, Carayol M, Achaintre D, Scalbert A, et al. . Metabolic profiles of male meat eaters, fish eaters, vegetarians, and vegans from the EPIC-Oxford cohort. Am J Clin Nutr. (2015) 102:1518–26. doi: 10.3945/ajcn.115.111989, PMID: PubMed DOI PMC

Richter M, Boeing H, Grünewald-Funk D, Heseker H, Kroke A, Leschik-Bonnet E, et al. . Vegan diet position of the German nutrition society (DGE). Ernaehrungs Umschau international |. (2016):4. doi: 10.4455/eu.2016.021 DOI

Wang F, Wan Y, Yin K, Wei Y, Wang B, Yu X, et al. . Lower circulating branched-chain amino acid concentrations among vegetarians are associated with changes in gut microbial composition and function. Mol Nutr Food Res. (2019) 63:e1900612. doi: 10.1002/mnfr.201900612, PMID: PubMed DOI

Iguacel I, Miguel-Berges ML, Gómez-Bruton A, Moreno LA, Julián C. Veganism, vegetarianism, bone mineral density, and fracture risk: a systematic review and meta-analysis. Nutr Rev. (2019) 77:1–18. doi: 10.1093/nutrit/nuy045 PubMed DOI

Alcorta A, Porta A, Tárrega A, Alvarez MD, Vaquero MP. Foods for plant-based diets: challenges and innovations. Food Secur. (2021) 10:293. doi: 10.3390/foods10020293 PubMed DOI PMC

Haider S, Sima A, Kühn T, Wakolbinger M. The association between vegan dietary patterns and physical activity—a Cross-sectional online survey. Nutrients. (2023) 15:1847. doi: 10.3390/nu15081847, PMID: PubMed DOI PMC

Gallagher CT, Hanley P, Lane KE. Pattern analysis of vegan eating reveals healthy and unhealthy patterns within the vegan diet. Public Health Nutr. (2022) 25:1310–20. doi: 10.1017/S136898002100197X, PMID: PubMed DOI PMC

Gehring J, Touvier M, Baudry J, Julia C, Buscail C, Srour B, et al. . Consumption of ultra-processed foods by Pesco-vegetarians, vegetarians, and vegans: associations with duration and age at diet initiation. J Nutr. (2021) 151:120–31. doi: 10.1093/jn/nxaa196, PMID: PubMed DOI

Pointke M, Pawelzik E. Plant-based alternative products: are they healthy alternatives? Micro- and macronutrients and nutritional scoring. Nutrients. (2022) 14:601. doi: 10.3390/nu14030601, PMID: PubMed DOI PMC

Curtain F, Grafenauer S. Plant-based meat substitutes in the flexitarian age: an audit of products on supermarket shelves. Nutrients. (2019) 11:2603. doi: 10.3390/nu11112603, PMID: PubMed DOI PMC

Gil Á, Martinez de Victoria E, Olza J. Indicators for the evaluation of diet quality. Nutr Hosp Suppl. (2015) 3:128–44. doi: 10.3305/nh.2015.31.sup3.8761 PubMed DOI

Kim S, Haines PS, Siega-Riz AM, Popkin BM. The diet quality index-international (DQI-I) provides an effective tool for Cross-National Comparison of diet quality as illustrated by China and the United States. J Nutr. (2003) 133:3476–84. doi: 10.1093/jn/133.11.3476 PubMed DOI

World Health Organization . Sustainable healthy diets: guiding principles. Food Agri Org. (2019)

Kronsteiner-Gicevic S, Bogl LH, Wakolbinger M, Müller S, Dietrich J, De Keyzer W, et al. . Development of the VEGANScreener, a tool for a quick diet quality assessment among vegans in Europe. Nutrients. (2024) 16:1344. doi: 10.3390/nu16091344, PMID: PubMed DOI PMC

Van Poppel MNM, Chinapaw MJM, Mokkink LB, Van Mechelen W, Terwee CB. Physical Activity Questionnaires for Adults A Systematic Review of Measurement Properties. Sports Med. (2010) 40:565–600. doi: 10.2165/11531930-000000000-00000 PubMed DOI

Vanderweele TJ. On the promotion of human flourishing. Vol. 114, Proceedings of the National Academy of Sciences of the United States of America. National Academy of Sciences; (2017). p. 8148–8156. PubMed PMC

WWziak-Biaaowolska D, McNeely E, VanderWeele T. Flourish index and secure flourish index development and validation. SSRN Electron J. (2017). doi: 10.2139/ssrn.3145336 DOI

AaT B, Steer RA, Brown GKBDI-II. Beck depression inventory: Manual. Second ed. San Antonio, Tex., Boston: Psychological Corp.; Harcourt Brace; (1996).

de la Fuente-Arrillaga C, Vázquez Ruiz Z, Bes-Rastrollo M, Sampson L, Martinez-González MA. Reproducibility of an FFQ validated in Spain. Public Health Nutr. (2010) 13:1364–72. doi: 10.1017/S1368980009993065 PubMed DOI

Fernández-Ballart JD, Piñol JL, Zazpe I, Corella D, Carrasco P, Toledo E, et al. . Relative validity of a semi-quantitative food-frequency questionnaire in an elderly Mediterranean population of Spain. Br J Nutr. (2010) 103:1808–16. doi: 10.1017/S0007114509993837, PMID: PubMed DOI

Dyett P, Rajaram S, Haddad E, Sabate J. Evaluation of a validated food frequency questionnaire for self-defined vegans in the United States. Nutrients. (2014) 6:2523–39. doi: 10.3390/nu6072523, PMID: PubMed DOI PMC

Day N, Oakes S, Luben R, Bingham S, Welch A, Wareham N. EPIC-Norfolk: study design and characteristics of the cohort. European prospective investigation of Cancer. Br J Cancer. (1999) 80 Suppl 1:95–103. PubMed

Margetts BM, Nelson M. Design concepts in nutritional epidemiology. Second ed. Oxford: Oxford University Press; (1997).

Hulley SB, Cummings SR, Browner WS, Grady D, Newman TB. Designing clinical research. LWW: a Wolters Kluwer business. (2013).

World Medical Association Declaration of Helsinki . World medical association declaration of Helsinki: ethical principles for medical research involving human subjects. JAMA. (2013) 310:2191. doi: 10.1001/jama.2013.281053 PubMed DOI

Segovia-Siapco G, Rajaram S, Sabaté J. Proceedings of the seventh international congress on vegetarian nutrition: introduction. Adv Nutr. (2019) 10:S273–4. doi: 10.1093/advances/nmy088, PMID: PubMed DOI PMC

Aleksandrowicz L, Green R, Joy EJM, Smith P, Haines A. The impacts of dietary change on greenhouse gas emissions, land use, water use, and health: a systematic review. PLoS One. (2016) 11:e0165797. doi: 10.1371/journal.pone.0165797 PubMed DOI PMC

Willett W, Rockström J, Loken B, Springmann M, Lang T, Vermeulen S, et al. ., Food in the Anthropocene: The EAT–lancet commission on healthy diets from sustainable food systems. Vol. 393, Lancet; (2019). p. 393:447–492, doi: 10.1016/S0140-6736(18)31788-4 PubMed DOI

Marrone G, Guerriero C, Palazzetti D, Lido P, Marolla A, Di Daniele F, et al. . Vegan diet health benefits in metabolic syndrome. Nutrients. (2021) 13:817. doi: 10.3390/nu13030817, PMID: PubMed DOI PMC

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. doi: 10.1080/07315724.2020.1869625 PubMed DOI

Sakkas H, Bozidis P, Touzios C, Kolios D, Athanasiou G, Athanasopoulou E, et al. . Nutritional status and the influence of the vegan diet on the gut microbiota and human health. Medicina. (2020) 56:88. doi: 10.3390/medicina56020088, PMID: PubMed DOI PMC

Allès B, Baudry J, Méjean C, Touvier M, Péneau S, Hercberg S, et al. . Comparison of sociodemographic and nutritional characteristics between self-reported vegetarians, vegans, and meat-eaters from the nutrinet-santé study. Nutrients. (2017) 9:1023. doi: 10.3390/nu9091023, PMID: PubMed DOI PMC

Satija A, Bhupathiraju SN, Spiegelman D, Chiuve SE, Manson JAE, Willett W, et al. . Healthful and unhealthful plant-based diets and the risk of coronary heart disease in U.S adults. J Am Coll Cardiol. (2017) 70:411–22. doi: 10.1016/j.jacc.2017.05.047, PMID: PubMed DOI PMC

Sobiecki JG, Appleby PN, Bradbury KE, Key TJ. High compliance with dietary recommendations in a cohort of meat eaters, fish eaters, vegetarians, and vegans: results from the European prospective investigation into Cancer and nutrition-Oxford study. Nutr Res. (2016) 36:464–77. doi: 10.1016/j.nutres.2015.12.016, PMID: PubMed DOI PMC

Krebs-Smith SM, Pannucci TE, Subar AF, Kirkpatrick SI, Lerman JL, Tooze JA, et al. . Update of the healthy eating index: HEI-2015. J Acad Nutr Diet. (2018) 118:1591–602. doi: 10.1016/j.jand.2018.05.021, PMID: PubMed DOI PMC

Bez NS, Haddad J, Tedde GS, Rose K, Ivanov AV, Milazzo M, et al. . Development of a diet quality score and adherence to the Swiss dietary recommendations for vegans. J Health Popul Nutr. (2024) 43:17. doi: 10.1186/s41043-024-00498-3, PMID: PubMed DOI PMC

Newgard CB. Metabolomics and metabolic diseases: where do we stand? Cell Metab. (2017) 25:43–56. doi: 10.1016/j.cmet.2016.09.018, PMID: PubMed DOI PMC

Guasch-Ferré M, Bhupathiraju SN, Hu FB. Use of metabolomics in improving assessment of dietary intake. Clin Chem. (2018) 64:82–98. doi: 10.1373/clinchem.2017.272344, PMID: PubMed DOI PMC

Brennan L, Hu FB. Metabolomics-based dietary biomarkers in nutritional epidemiology—current status and future opportunities. Mol Nutr Food Res. (2019) 63:e1701064. doi: 10.1002/mnfr.201701064, PMID: PubMed DOI