Urinary α-Carboxyethyl Hydroxychromanol (α-CEHC)-A Biomarker of Vitamin E Intake: A Scoping Review

Urinary α-carboxyethyl hydroxychromanol (α-CEHC), the terminal catabolic product of α-tocopherol, has been proposed as a noninvasive biomarker of vitamin E intake. Existing human studies vary substantially in design, population characteristics, analytical methods, and reporting practices, limiting the comparability of findings across the literature. The objective of this scoping review is to systematically map all human evidence evaluating urinary α-CEHC in relation to vitamin E intake, catabolism, or health status. The protocol for this scoping review was registered in Open Science Framework on 26 October 2025 (https://osf.io/a7gkv). Following Joanna Briggs Institute (JBI) methodology and PRISMA-ScR reporting standards, we searched MEDLINE, EMBASE, Web of Science, CENTRAL, and CINAHL. The initial literature search yielded 586 records. Two reviewers independently screened all records, extracted data using piloted forms, and organized findings into thematic domains reflecting biomarker responsiveness, methodological variability, and clinical contexts. A total of 34 studies were included, representing a wide range of vitamin E interventions, urine collection approaches, and analytical methods. Study heterogeneity was substantial. The increases in urinary α-CEHC excretion in response to supplemental vitamin E dose reported in 10 intervention studies were highly correlated (R² = 0.7819, P < 0.0001). Overall, urinary α-CEHC appears to be a promising integrated measure of vitamin E catabolism; however, methodological inconsistencies across studies limit the ability to compare results between individuals on routine diets. Standardized urine collection protocols, conjugate handling procedures, normalization strategies, and analytical techniques will be necessary before α-CEHC can be validated for clinical application. This study was registered in Open Science Framework on 26 October, 2025 (https://osf.io/a7gkv) as a scoping review.