Mental health research in vegans and vegetarians: a critical commentary on ethics, empathy, and epidemiology

This paper critiques the widespread use of epidemiological comparisons between vegans and omnivores in mental health research. While such studies often attribute outcomes to nutritional deficiencies or benefits, they overlook key psychosocial and ethical factors, including elevated empathy, social stigma, and inconsistent dietary classifications. These confounds undermine causal inference and render observational findings conceptually flawed. Within-vegan analyses of diet quality offer more valid insights. We argue that future research could incorporate targeted psychological screening to better capture the ethical and social stressors unique to veganism, improving the accuracy and relevance of mental health assessments in both research and policy contexts.