Lycopene, beta-carotene, and colorectal adenomas 
.png) |
Lycopene, beta-carotene, and colorectal adenomas.
Erhardt JG, Meisner C, Bode JC, Bode C.
Department of Physiology of Nutrition, Hohenheim University, Garbenstrasse 28, D-70599 Stuttgart, Germany.
BACKGROUND: Epidemiologic studies found that high tomato intakes reduce the risk of colorectal cancers. This beneficial effect is assumed to be caused by high intakes of lycopene, a carotenoid with strong antioxidant activity that is present predominantly in tomatoes. OBJECTIVE: We assessed the relation between plasma lycopene concentrations and colorectal adenomas, the precursors for most colorectal cancers. In addition, the concentrations of 2 other antioxidants, beta-carotene and alpha-tocopherol, were measured. DESIGN: White subjects undergoing a complete colonoscopy were included in the study (73 with adenomas, 63 without any polyps, and 29 with hyperplastic polyps). A detailed dietary history and information on alcohol consumption and smoking habits were collected from all subjects. Plasma lycopene, beta-carotene, and alpha-tocopherol concentrations were measured by using HPLC. RESULTS: Patients with adenomas and control subjects without polyps did not differ significantly in body mass index; intakes of energy, fat, protein, carbohydrates, fiber, beta-carotene, and alcohol; or prevalence of smoking, but patients with adenomas were slightly older. The median plasma lycopene concentration was significantly lower in the adenoma group than in the control group (-35%; P = 0.016). The median plasma beta-carotene concentration also tended to be lower in the adenoma group (-25.5%), but the difference was not significant. In the multiple logistic regression, only smoking (odds ratio: 3.02; 95% CI: 1.46, 6.25; P = 0.003) and a plasma lycopene concentration < 70 microg/L (odds ratio: 2.31; 1.12, 4.77; P = 0.023) were risk factors for adenomatous polyps. Patients with hyperplastic polyps did not differ significantly from control subjects in any variable. CONCLUSION: Our findings support the hypothesis that lycopene contributes to the protective effect of high tomato intakes against the risk of colorectal adenomas.
PMID: 14668286 [PubMed - indexed for MEDLINE]
|
|
Oxidative conversion of carotenoids 
.png){kind=small}
.png){kind=small}
