Validity of Urinary Metabolites α‐CEHC and α‐CMBHC as Biomarkers of α‐Tocopherol Consumption: Correlations with Dietary and Plasma α Tocopherol

There are no functional biomarkers of vitamin E status and plasma concentrations are a poor indicator of intake. Therefore, clarity on the relationship between α‐tocopherol (α‐T) intake with urinary vitamin E metabolites (α‐CEHC or α‐CMBHC) is needed to discern the utility of the latter as biomarkers in human studies. We examined in subjects (n=235) from Los Angeles, relationships between intake (via 24 h recall), lipid‐adjusted plasma levels, and urinary α‐CEHC or α‐CMBHC. In a subset who did not consume supplemental α‐T (n=202), Pearson correlation analysis of log‐transformed data showed stronger correlations between dietary α‐T and urinary α‐CEHC (r=0.38, p< .001) or α‐CMBHC ( r = 0.34, p < 0.001), than between dietary and plasma α‐T ( r = 0.21; p = 0.003) or between plasma α‐T and urinary α‐CEHC (r=.23, p < 0.001) or α‐CMBHC ( r = 0.20; p < 0.05). In the subset of supplemental vitamin E users (n=33), the association of dietary α‐T and urinary α‐CEHC (r=0.44, p<0.01) was strong, but that of dietary α‐T with α‐CMBHC was not significant. These observations suggest that urinary levels of α‐CEHC might serve as a reliable biomarker of α‐T intake. Support provided by R01CA105048 and R01DK081761.