Kathryn J. Hughes¹, Susan T. Mayne^1,2, Jeffrey B. Blumberg³, Judy D. Ribaya-Mercado³, Elizabeth J. Johnson³ and Brenda Cartmel^1,2

¹Yale School of Public Health, New Haven, Connecticut, U.S. ²Yale Comprehensive Cancer Center, New Haven, Connecticut, U.S. ³Jean Mayer USDA HNRCA at Tufts University, Boston, Massachusetts, U.S.

Abstract

Diets high in fruits and vegetables are generally believed protective against several chronic diseases. One suggested mechanism is a reduction in oxidative stress. The carotenoids, nutrients found in colored fruits and vegetables, possess antioxidant properties in vitro, but their role in humans is less well documented. The aim of this cross-sectional study was to explore the relationships between the most abundant plasma carotenoids (alpha-carotene, beta-carotene, lycopene, lutein, zeaxanthin and beta-cryptoxanthin), as well as grouped carotenoids (total xanthophylls, carotenes and carotenoids), and urinary excretion of the F₂-isoprostanes (F₂-IsoPs), stable and specific biomarkers of oxidative damage to lipids. Two F₂-IsoP measures were utilized: total F₂-IsoPs and 8-iso-PGF_2α. The study population (N = 52) was drawn from a study among patients curatively treated for early-stage head and neck cancer. Unadjusted linear regression analyses revealed significant inverse associations between plasma lutein, total xanthophylls and both F₂-IsoP measures at baseline. After control for potential confounders, all individual and grouped xanthophylls remained inversely associated with the F₂-IsoP measures, but none of these associations achieved significance. The carotenes were not inversely associated with total F₂-IsoPs or 8-iso-PGF_2a concentrations. The finding of consistent inverse associations between individual and grouped xanthophylls, but not individual and grouped carotenes, and F₂-IsoPs is intriguing and warrants further investigation.