The Associations Between Vegetarian and Vegan Diets and Orthorexia Nervosa Symptoms in Adults: A Systematic Review and Meta-Analysis.

OBJECTIVE To synthesize the evidence on the associations between vegetarian and/or vegan diets (VVDs) and symptoms of orthorexia nervosa (ON) compared with omnivorous diets in the adult population. METHOD Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and the Meta-analyses of Observational Studies in Epidemiology (MOOSE) guidelines, we conducted a systematic review and meta-analysis. We searched the MEDLINE/PubMed, Embase/Scopus, PsycINFO, and Web of Science databases up to June 17, 2025, with no language or date restrictions. Random effects models with the Sidik-Jonkman method were used to estimate pooled effect sizes. RESULTS The meta-analysis included 26 cross-sectional studies with a total of 23,783 participants (72.0% female; mean age range: 19.6-51.0 years). Adults who followed VVDs had moderately higher ON symptoms compared to omnivores (standardized mean differences using Cohen's d index = 0.46; 95% confidence interval [CI]: 0.33, 0.60; inconsistency index [I2] = 81.0%). Additionally, categorical data revealed that VVD adherents were approximately twice as likely to report ON symptoms as omnivores (odds ratio = 1.99; 95% CI: 1.21-3.25; I2 = 92.8%). Vegetarians and vegans were similarly associated with ON symptoms compared with omnivorous (p = 0.855). DISCUSSION Adherence to VVD is associated with higher ON symptoms in young and middle-aged adults. However, these results should be interpreted with caution due to high heterogeneity and the low overall methodological quality of the exclusively cross-sectional studies included. Higher-quality longitudinal studies using validated assessment tools are needed to establish clearer causal relationships and inform clinical screening and intervention strategies.

• Publication year

  2025

• Venue

  International Journal of Eating Disorders

• Publication date

  2025-11-13

• Fields of study

  Agricultural and Food Sciences, Medicine

• Identifiers
  DOI 10.1002/eat.24596PMID 41230622PMCID PMC12979968
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar, PubMed

• No claims are published for this paper.

• No concepts are published for this paper.

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