Urinary -carboxyethyl hydroxychroman can be used as a predictor of -tocopherol adequacy, as demonstrated in the Energetics Study

From General Internal Medicine, University of California, Los Angeles, Los Angeles, CA and School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR.
American Journal of Clinical Nutrition (Impact Factor: 6.77). 09/2012; 96(4):801-9. DOI: 10.3945/ajcn.112.038620
Source: PubMed


Other than the in vitro erythrocyte hemolysis test, no valid biomarkers of vitamin E status currently exist.
We hypothesized that the urinary vitamin E metabolite α-carboxyethyl hydroxychroman (α-CEHC) could serve as a biomarker.
The relations between urinary α-CEHC, plasma α-tocopherol, and vitamin E intakes were assessed by using a previously validated multipass, Web-based, 24-h self-administered dietary recall, and we concurrently collected plasma and 24-h urine samples from 233 participants of both sexes.
Median vitamin E intakes were 9.7 mg α-tocopherol/d. Intakes were correlated with plasma α-tocopherol (R = 0.40, P < 0.001) and urinary α-CEHC (R = 0.42, P < 0.001); these correlations were essentially unchanged after multivariate adjustments. On the basis of multiple regression analysis, urinary α-CEHC excretion increased by ∼0.086 μmol/g creatinine (95% CI: 0.047, 0.125) for every 1-mg (2.3-μmol) increase in dietary α-tocopherol. Urinary α-CEHC excretion remained at a plateau (median: 1.39 μmol/g creatinine) until dietary intakes of α-tocopherol exceeded 9 mg α-tocopherol/d. The inflection point at which vitamin E metabolism increased was estimated to be at an intake of 12.8 mg α-tocopherol/d. Daily excretion of >1.39 μmol α-CEHC/g creatinine is associated with a greater than adequate α-tocopherol status, as evidenced by increased vitamin E metabolism and excretion.
Thus, urinary α-CEHC is a valid biomarker of α-tocopherol status that can be used to set a value for the Estimated Adequate Requirement of vitamin E.

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