Plasma, Prostate and Urine Levels of Tocopherols and Metabolites in Men after Supplementation with a γ-Tocopherol-Rich Vitamin E Mixture

Abstract

The vitamin E forms γ- and δ-tocopherols (T) inhibit carcinogenesis in animal models; nevertheless, their cancer preventive activities in humans are uncertain. As an initial step to address this issue, we conducted a pilot phase 0 trial to determine the levels of tocopherols and their metabolites in prostate cancer patients undergoing radical prostatectomy. The patients were randomized to no supplementation or two capsules of a γ-T-rich vitamin E mixture daily for 7 or 14 day prior to prostatectomy. Blood and urine samples were collected before supplementation and on the day of surgery, along with prostate tissue, for analysis of tocopherols and their metabolites. Estimated blood loss during surgery was not significantly different across treatment arms and there were no reported adverse events. Prostate tissue levels of γ-T and δ-T were increased after 14 day of supplementation. Their side-chain degradation metabolites (CEHCs and CMBHCs) were significantly elevated in plasma, prostate and urine samples after supplementation for 7 or 14 day. In conclusion, supplementation with γ-T-rich vitamin E increased the prostate levels of γ-T and δ-T. The use of pure γ-T, δ-T or tocopherol mixtures with higher ratio of γ-T or δ-T to α-T is recommended for future studies.

Disclosure Statement

The authors have no conflicts of interest including any financial, personal, or other relationships with people or organizations that could influence the present article.

Author Contribution Statement

S. Goodin, I. Kim, C. Yang planned the study. I. Kim and M. Orlick conducted the clinical procedures and studies. C. Yang and M. Lee conducted the laboratory analysis of tocopherols and tocopherol metabolites. S. Goodin and X. Zheng coordinated the studies. W. Shih conducted the statistical analyses. C. Yang, S. Goodin, I. Kim and W. Shih wrote the manuscript.

Institutional Approval

The trial was approved by the Institutional Review Board of Rutgers, The State University of New Jersey, and the Robert Wood Johnson Medical School (NCT 00895115).

Additional information

Funding

This trial was supported by NCI CCSG 72720 (S. Goodin, I. Kim, W. Shih, M. Orlick, X. Zheng, C. Yang) and the John L. Colaizzi Chair Endowment Fund (C. Yang).