Beyond Body Weight: Mapping Vitamin, Mineral, and Trace-Element Status in Anorexia Nervosa—Scoping Review

Introduction: Background: Anorexia nervosa (AN) is associated with severe dietary restriction and multisystem effects of undernutrition, but biochemical micronutrient status does not necessarily parallel dietary intake or body weight. This scoping review mapped biological evidence on vitamin, mineral, trace-element, and electrolyte status in AN. Methods: The review was structured using JBI scoping review methodology and is reported according to PRISMA-ScR. PubMed/MEDLINE, Scopus, Web of Science Core Collection, and supplementary Google Scholar searching were used from inception to 30 March 2026, together with backward reference-list screening. Eligibility was defined using the Population–Concept–Context framework. Original human studies containing a clearly identifiable AN population and reporting biological micronutrient markers were eligible; refeeding studies, case reports/series, and diagnostically mixed cohorts were retained when relevant but were distinguished from AN-specific comparative or cohort evidence. Data were charted by design, population, biological matrix, timing, and nutrient outcome and synthesized narratively. Results: Database searching identified 621 records; 109 studies met eligibility criteria, and reference-list screening added 27 studies, yielding 136 included sources. Findings were heterogeneous and did not support universal biochemical depletion. Phosphorus was frequently preserved at admission but declined during refeeding in many cohorts. Potassium, sodium, and magnesium abnormalities were most evident in medically unstable, purging, or refeeding contexts. Serum calcium was commonly preserved despite impaired bone health. Iron deficiency was uncommon in many cohorts despite anemia and altered ferritin, transferrin, or hepcidin. Selenium, zinc, and vitamin D were recurrently low in several studies, whereas vitamin B12 was more often normal or elevated than deficient. Conclusions: AN is characterized by context-dependent micronutrient dysregulation rather than uniform deficiency. Interpretation should account for study design, illness stage, purging behavior, supplementation, refeeding, biological matrix, and the limitations of circulating biomarkers. Normal serum or plasma concentrations do not necessarily exclude depleted tissue stores, functional insufficiency, or refeeding risk. Interpretation is prioritized by study design, sample size, biological matrix and treatment stage rather than numerical direction-of-finding counts. This review maps monitoring-relevant abnormalities but does not establish the efficacy of supplementation strategies.