Positive Health Online

Abstract

FREEMAN and colleagues, Midwest Center for Health Services and Policy Research, Department of Veterans Affairs, Edward Hines, Jr. Hospital, Hines IL, USA conducted a study to evaluate how prostatic levels of antioxidants relate to plasma levels and self-reported usual dietary intake, which may aid in interpreting studies of antioxidant exposure and prostate cancer risk .

Background

Methodology

Plasma and prostatic tissue levels of tocopherols, carotenoids and retinol were measured in 47 men undergoing radical prostatectomy or transurethral prostatectomy between July 1996 and April 1997. Dietary intake was measured using a questionnaire.

Results

Prostatic levels of tocopherols and carotenoids (but not retinol) were significantly correlated with plasma levels ; the strongest correlations were associated with lycopene, beta-carotene and gamma-tocopherol (0.56, 0.54 and 0.52, respectively). Relative concentrations of tocopherols and carotenoids in prostate tissue were proportionate to those in plasma; however, no correlation between prostatic levels and reported dietary intake was observed. Adjustment for energy intake, body mass index and serum lipids did not impact these relations.

Conclusion

These data suggest that plasma levels of tocopherols and carotenoids better reflect prostatic exposure then self-reported usual dietary intake.

References

Freeman VL et al. Prostatic levels of tocopherols, carotenoids, and retinol in relation to plasma levels and self-reported usual dietary intake. American Journal of Epidemiology 151(2): 109-18. 15 Jan 2000.

Comment

Another nail in the coffin for the reliability of food questionnaires frequently used in epidemiological research.