Plasma levels of beta-carotene, lycopene, canthaxanthin, retinol, and alpha- and tau-tocopherol in cervical intraepithelial neoplasia and cancer

Abstract

Epidemiological studies continue to identify an association of dietary antioxidant micronutrients in cancer prevention. A number of case-control and cohort studies have demonstrated a relationship between high intake of foods rich in carotenoids, tocopherols, and vitamin C with a reduced risk of certain human malignancies. The purpose of this study was to investigate the comparative plasma levels of a profile of known dietary antioxidants, namely, beta-carotene, lycopene, canthaxanthin, retinol, alpha-tocopherol, and tau-tocopherol. The target population was women with a histopathological diagnosis of cervical intraepithelial neoplasia (CIN) or cervical cancer and a control group. All women resided in the same catchment area (Bronx Borough, New York City) and were of similar inner-city socioeconomic backgrounds representing a fairly homogenous population group. A cross-sectional sample of 235 women was recruited with informed consent. Plasma nutrient levels were measured by reverse-phase high pressure liquid chromatography under study codes. The mean plasma levels of carotenoids (beta-carotene, lycopene, and canthaxanthin), as well as alpha-tocopherol, were significantly lower in women with CIN and cervical cancer. In contrast, the mean plasma level of tau-tocopherol was higher among patients with CIN, while the mean plasma level of retinol was comparable among the groups. There were significant linear trends for all three carotenoids and quadratic trends for alpha- and tau-tocopherol with the degree of cervical histopathology. Plasma beta-carotene concentrations in cigarette smokers were significantly lower regardless of cervical pathology, whereas plasma lycopene and canthaxanthin levels were significantly lower in smokers with CIN. The findings of a decrease in all plasma antioxidant nutrient levels except tau-tocopherol in women with CIN and cancer suggest a potential role for antioxidant deficiency in the pathogenesis of CIN and carcinoma of the cervix, which requires further investigation.