Background: Other than the in vitro erythrocyte hemolysis test, no valid biomarkers of vitamin E status currently exist. Objective: We... » More

Background: Other than the in vitro erythrocyte hemolysis test, no

valid biomarkers of vitamin E status currently exist.

Objective: We hypothesized that the urinary vitamin E metabolite

a-carboxyethyl hydroxychroman (a-CEHC) could serve as a biomarker.

Design: The relations between urinary a-CEHC, plasma a-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.

Results: Median vitamin E intakes were 9.7 mg a-tocopherol/d.

Intakes were correlated with plasma a-tocopherol (R = 0.40, P ,

0.001) and urinary a-CEHC (R = 0.42, P , 0.001); these correlations

were essentially unchanged after multivariate adjustments. On

the basis of multiple regression analysis, urinary a-CEHC excretion

increased by w0.086 mmol/g creatinine (95% CI: 0.047, 0.125) for

every 1-mg (2.3-mmol) increase in dietary a-tocopherol. Urinary

a-CEHC excretion remained at a plateau (median: 1.39 mmol/g

creatinine) until dietary intakes of a-tocopherol exceeded 9 mg

a-tocopherol/d. The inflection point at which vitamin E metabolism

increased was estimated to be at an intake of 12.8 mg a-tocopherol/

d. Daily excretion of >1.39 mmol a-CEHC/g creatinine is associated

with a greater than adequate a-tocopherol status, as evidenced

by increased vitamin E metabolism and excretion.

Conclusion: Thus, urinary a-CEHC is a valid biomarker of a-tocopherol

status that can be used to set a value for the Estimated Adequate

Requirement of vitamin E.

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