Lycopene, beta-carotene, and colorectal adenomas.
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.


METHODS
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.


CONCLUSIONS
Our findings support the hypothesis that lycopene contributes to the protective effect of high tomato intakes against the risk of colorectal adenomas.
Erhardt
Juergen G
JG
Department of Physiology of Nutrition, Hohenheim University, Garbenstrasse 28, D-70599 Stuttgart, Germany.
Meisner
Christoph
C
Bode
J Christian
JC
Bode
Christiane
C
D000236:Adenoma / Q000097:blood* / Q000209:etiology; D000328:Adult; D000367:Age Factors; D000368:Aged; D000975:Antioxidants / Q000378:metabolism*; D002338:Carotenoids / Q000097:blood*; D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid; D003111:Colonic Polyps / Q000097:blood / Q000209:etiology; D015179:Colorectal Neoplasms / Q000097:blood* / Q000209:etiology; D004032:Diet; D005260:Female; D006801:Humans; D016015:Logistic Models; D000077276:Lycopene; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D024502:alpha-Tocopherol / Q000097:blood; D019207:beta Carotene / Q000097:blood*
D000975:Antioxidants; D019207:beta Carotene; D002338:Carotenoids; D024502:alpha-Tocopherol; D000077276:Lycopene