Koch F, Heuer T, Krems C, Claupein E. Meat consumers and non-meat consumers in Germany: a characterisation based on results of the German National Nutrition Survey II. J Nutr Sci. 2019;8:e21. https://www.cambridge.org/core/product/identifier/S204867901900017X/type/journal_article.

Article  PubMed  PubMed Central  Google Scholar 

Wozniak H, Larpin C, de Mestral C, Guessous I, Reny JL, Stringhini S. Vegetarian, pescatarian and flexitarian diets: sociodemographic determinants and association with cardiovascular risk factors in a Swiss urban population. Br J Nutr. 2020;124(8):844–52. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7525113/.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Malek L, Umberger WJ. Distinguishing meat reducers from unrestricted omnivores, vegetarians and vegans: a comprehensive comparison of Australian consumers. Food Qual Prefer. 2021;88:104081. https://www.sciencedirect.com/science/article/pii/S0950329320303505.

Article  Google Scholar 

Neff RA, Edwards D, Palmer A, Ramsing R, Righter A, Wolfson J. Reducing meat consumption in the USA: a nationally representative survey of attitudes and behaviours. Public Health Nutr. 2018;21(10):1835–44. https://www.cambridge.org/core/journals/public-health-nutrition/article/reducing-meat-consumption-in-the-usa-a-nationally-representative-survey-of-attitudes-and-behaviours/D54CE3E1F9F8837EA87250E8781C0EDA.

Article  PubMed  PubMed Central  Google Scholar 

Springmann M, Wiebe K, Mason-D’Croz D, Sulser TB, Rayner M, Scarborough P. Health and nutritional aspects of sustainable diet strategies and their association with environmental impacts: a global modelling analysis with country-level detail. Lancet Planet Health. 2018;2(10):e451-61.

Article  PubMed  PubMed Central  Google Scholar 

Papier K, Tong TY, Appleby PN, Bradbury KE, Fensom GK, Knuppel A, et al. Comparison of major protein-source foods and other food groups in meat-eaters and non-meat-eaters in the EPIC-Oxford cohort. Nutrients. 2019;11(4):824.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Dagevos H. Finding flexitarians: current studies on meat eaters and meat reducers. Trends Food Sci Technol. 2021;114:530–9. https://www.sciencedirect.com/science/article/pii/S0924224421003952.

Article  CAS  Google Scholar 

Deutsche Gesellschaft für Ernährung e. V. 10 Regeln der DGE für eine vollwertige Ernährung überarbeitet. 2017. https://www.dge.de/ernaehrungspraxis/vollwertige-ernaehrung/10-regeln-der-dge/.

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. Lancet. 2019;393(10170):447–92. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)31788-4.

Article  PubMed  Google Scholar 

Montagnese C, Santarpia L, Buonifacio M, Nardelli A, Caldara AR, Silvestri E, et al. European food-based dietary guidelines: a comparison and update. Nutrition. 2015;31(7):908–15. https://www.sciencedirect.com/science/article/pii/S0899900715000076.

Article  PubMed  Google Scholar 

U.S. Department of Health and Human Services and U.S. Department of Agriculture. 8th edition. 2015–2020 dietary guidelines for Americans. https://health.gov/our-work/food-nutrition/previous-dietary-guidelines/2015.

Schüpbach R, Wegmüller R, Berguerand C, Bui M, Herter-Aeberli I. Micronutrient status and intake in omnivores, vegetarians and vegans in Switzerland. Eur J Nutr. 2017;56(1):283–93.

Article  PubMed  Google Scholar 

Craig WJ. Nutrition concerns and health effects of vegetarian diets. Nutr Clin Pract. 2010;25(6):613–20. https://onlinelibrary.wiley.com/doi/abs/10.1177/0884533610385707.

Article  PubMed  Google Scholar 

Position of the American Dietetic Association and Dietitians of Canada: vegetarian diets. Can J Diet Pract Res. 2003;64(2):62–81. https://dcjournal.ca/doi/10.3148/64.2.2003.62.

Neufingerl N, Eilander A. Nutrient intake and status in adults consuming plant-based diets compared to meat-eaters: a systematic review. Nutrients. 2021;14(1):29. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8746448/.

Article  PubMed  PubMed Central  Google Scholar 

Pawlak R, Lester SE, Babatunde T. The prevalence of cobalamin deficiency among vegetarians assessed by serum vitamin B12: a review of literature. Eur J Clin Nutr. 2014;68(5):541–8. https://www.nature.com/articles/ejcn201446.

Article  CAS  PubMed  Google Scholar 

Davey GK, Spencer EA, Appleby PN, Allen NE, Knox KH, Key TJ. EPIC-Oxford: lifestyle characteristics and nutrient intakes in a cohort of 33 883 meat-eaters and 31 546 non-meat-eaters in the UK. Public Health Nutr. 2003;6(3):259–69.

Article  PubMed  Google Scholar 

Kwaśniewska M, Pikala M, Grygorczuk O, Waśkiewicz A, Stepaniak U, Pająk A, et al. Dietary antioxidants, quality of nutrition and cardiovascular characteristics among omnivores, flexitarians and vegetarians in Poland—the results of multicenter national representative survey WOBASZ. Antioxidants. 2023;12(2):222. https://www.mdpi.com/2076-3921/12/2/222.

Article  PubMed  PubMed Central  Google Scholar 

Dawczynski C, Weidauer T, Richert C, Schlattmann P, Dawczynski K, Kiehntopf M. Nutrient intake and nutrition status in vegetarians and vegans in comparison to omnivores - the Nutritional Evaluation (NuEva) study. Front Nutr. 2022;9:819106. https://www.frontiersin.org/articles/10.3389/fnut.2022.819106.

Article  PubMed  PubMed Central  Google Scholar 

Groufh-Jacobsen S, Larsson C, Daele WV, Margerison C, Mulkerrins I, Aasland LM, et al. Food literacy and diet quality in young vegans, lacto-ovo vegetarians, pescatarians, flexitarians and omnivores. Public Health Nutr. 2023:1–26. https://www.cambridge.org/core/journals/public-health-nutrition/article/food-literacy-and-diet-quality-in-young-vegans-lactoovo-vegetarians-pescatarians-flexitarians-and-omnivores/5F9C632866AB180435D84BC49F73FCBC.

von Elm E, Altman DG, Egger M, Pocock SJ, Gøtzsche PC, Vandenbroucke JP. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies. J Clin Epidemiol. 2008;61(4):344–9. https://www.jclinepi.com/article/S0895-4356(07)00436-2.

Article  Google Scholar 

Bruns A, Mueller M, Schneider I, Hahn A. Application of a modified healthy eating index (HEI-Flex) to compare the diet quality of flexitarians, vegans and omnivores in Germany. Nutrients. 2022;14(15):3038. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9330316/.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Bundesanstalt für Landwirtschaft und Ernährung RM Kritische Infrastruktur Landwirtschaft, Bonn. Bericht zur Markt- und Versorgungslage Fleisch 2018. 2018. https://www.ble.de/DE/BZL/Daten-Berichte/Fleisch/fleisch_node.html.

Agricultural output - meat consumption - OECD data. Organisation for Economic Co-operation and Development (OECD). Per capita meat consumption in the EU28. http://data.oecd.org/agroutput/meat-consumption.htm.

Frey I, Berg A, Grathwohl D, Keul J. Freiburger Fragebogen zur körperlichen Aktivität-Entwicklung. Prüfung und Anwendung Soz Präventivmed. 1999;44(2):55–64. https://doi.org/10.1007/BF01667127.

Article  CAS  PubMed  Google Scholar 

Eknoyan G. Adolphe Quetelet (1796–1874)—the average man and indices of obesity. Nephrol Dial Transplant. 2008;23(1):47–51. https://doi.org/10.1093/ndt/gfm517.

Article  PubMed  Google Scholar 

Fedosov SN, Brito A, Miller JW, Green R, Allen LH. Combined indicator of vitamin B12 status: modification for missing biomarkers and folate status and recommendations for revised cut-points. Clin Chem Lab Med. 2015;53(8):1215–25.

Article  CAS  PubMed  Google Scholar 

DGE - ÖGE - SGE. D-A-C-H-Referenzwerte für die Nährstoffzufuhr. 2019. https://www.dge.de/wissenschaft/referenzwerte/gesamt/.

European Food Safety Authority E. www.efsa.europa.eu. 2019. Dietary reference values for the EU. https://multimedia.efsa.europa.eu/drvs/index.htm.

de Benoist B. Conclusions of a WHO Technical Consultation on folate and vitamin B12 deficiencies. Food Nutr Bull. 2008;29:S238–44. https://doi.org/10.1177/15648265080292S129.

Article  PubMed  Google Scholar 

Herrmann W, Schorr H, Bodis M, Knapp JP, Müller A, Stein G, et al. Role of homocysteine, cystathionine and methylmalonic acid measurement for diagnosis of vitamin deficiency in high-aged subjects. Eur J Clin Invest. 2000;30(12):1083–9.

Article  CAS  PubMed  Google Scholar 

Herrmann W, Obeid R, Schorr H, Geisel J. Functional vitamin B12 deficiency and determination of holotranscobalamin in populations at risk. Clin Chem Lab Med. 2003;41(11):1478–88.

Article  CAS  PubMed  Google Scholar 

Hvas AM, Nexo E. Holotranscobalamin as a predictor of vitamin B12 status. Clin Chem Lab Med. 2003;41(11):1489–92.

Article  CAS  PubMed  Google Scholar 

Malinow MR, Bostom AG, Krauss RM. Homocyst(e)ine, diet, and cardiovascular diseases: a statement for healthcare professionals from the Nutrition Committee, American Heart Association. Circulation. 1999;99(1):178–82.

Article  CAS  PubMed  Google Scholar 

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(5):785–94.

Article  CAS  PubMed  Google Scholar 

Lips P, Cashman KD, Lamberg-Allardt C, Bischoff-Ferrari HA, Obermayer-Pietsch B, Bianchi ML, et al. Current vitamin D status in European and Middle East countries and strategies to prevent vitamin D deficiency: a position statement of the European Calcified Tissue Society. Eur J Endocrinol. 2019;180(4):P23-54. https://eje.bioscientifica.com/view/journals/eje/180/4/EJE-18-0736.xml.

Article  CAS  PubMed  Google Scholar 

Amrein K, Scherkl M, Hoffmann M, Neuwersch-Sommeregger S, Köstenberger M, Tmava Berisha A, et al. Vitamin D deficiency 2.0: an update on the current status worldwide. Eur J Clin Nutr. 2020;74(11):1498–513. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7091696/.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Gellert S, Ströhle A, Bitterlich N, Hahn A. Higher prevalence of vitamin D deficiency in German pregnant women compared to non-pregnant women. Arch Gynecol Obstet. 2017;296(1):43–51. https://doi.org/10.1007/s00404-017-4398-5.

Article  CAS  PubMed  Google Scholar 

Maretzke F, Bechthold A, Egert S, Ernst JB, Melo van Lent D, Pilz S, et al. Role of vitamin D in preventing and treating selected extraskeletal diseases—an umbrella review. Nutrients. 2020;12(4):969.