title: Diet potentiates the UV-carcinogenic response to beta-carotene.
abstract: The role of beta-carotene as an anticancer agent has been questioned as a result of clinical trials in which the incidence of nonmelanoma skin cancer was unchanged in patients receiving a beta-carotene supplement and in beta-carotene-supplemented smokers who suffered a significant increase in lung cancer occurrence. In laboratory studies, beta-carotene-supplemented semidefined diets, in contrast to earlier studies employing commercial closed-formula diets, not only failed to provide a protective effect to ultraviolet (UV) carcinogenesis but resulted in significant exacerbation. A rationale for this distinct carcinogenic response to beta-carotene rests with the stability of the carotenoid radical cation, believed to be dependent on the presence of other antioxidants for rapid repair, and suggests that response to beta-carotene depends on the presence and interaction with other dietary factors. Here, we report that diet potentiates beta-carotene-mediated exacerbation of UV carcinogenesis. Although the dietary factor(s) responsible for this effect is unidentified, these studies underscore the potential risk of beta-carotene supplementation in free-living populations where dietary status is widely varied.
authors.affiliation: Baylor College of Medicine and Veterans Affairs Medical Center, Houston, TX 77030, USA.
authors.forename: H S
authors.initials: HS
authors.lastname: Black
authors.forename: G
authors.initials: G
authors.lastname: Okotie-Eboh
authors.forename: J
authors.initials: J
authors.lastname: Gerguis
mesh_terms: D000818:Animals; D016588:Anticarcinogenic Agents / Q000009:adverse effects / Q000494:pharmacology* / Q000627:therapeutic use; D004032:Diet; D019587:Dietary Supplements; D004817:Epidermis / Q000737:chemistry; D005260:Female; D051379:Mice; D008812:Mice, Hairless; D009381:Neoplasms, Radiation-Induced / Q000209:etiology / Q000517:prevention & control*; D011897:Random Allocation; D012878:Skin Neoplasms / Q000209:etiology / Q000517:prevention & control*; D013997:Time Factors; D014466:Ultraviolet Rays / Q000009:adverse effects; D019207:beta Carotene / Q000009:adverse effects / Q000032:analysis / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D016588:Anticarcinogenic Agents; D019207:beta Carotene