科学家以往研究认为，经常食用含有粗纤维食品，例如全麦面包可以减少肠癌的发病率。最新研究成果显示，或许起到防癌作用的是烘烤过的面包皮。但研究人员说，现在就说每天吃多少面包皮可预防肠癌为时尚早。
8月号《欧洲癌症预防杂志》刊登研究报告说，面包中对人体最有益的成分不是纤维质而是面包皮。这是因为在烘烤面包过程中会产生一种被称为Pronyl-lysine的抗氧化剂，这种物质可以预防肠癌，而它主要集中在面包皮中。
印度安纳马莱大学研究人员通过小白鼠试验检测出了Pronyl-lysine的确切作用。
研究人员把小白鼠暴露在可以引发肠癌的化学环境中，同时给予不同组别的白鼠含有Pronyl-lysine的面包皮。经过观察测算，科学家发现，每天食用面包皮的小白鼠早期癌症病变的几率降低了72％。
英国《每日邮报》21日援引研究人员的话说：“实验表明，持续吸收Pronyl-lysine可以显著降低早期癌变的几率。”（生物谷Bioon.com）
生物谷推荐原始出处：
European Journal of Cancer Prevention:doi: 10.1097/CEJ.0b013e32832945a6
Inhibitory effect of bread crust antioxidant pronyl-lysine on two different categories of colonic premalignant lesions induced by 1,2-dimethylhydrazine
Panneerselvam, Jayabal; Aranganathan, Selvaraj; Nalini, Namasivayam
Colorectal malignancies continue to be one of the most frequent and life-threatening diseases throughout the world. Pronyl-lysine, a product obtained from bread crust, is a potent free radical scavenging antioxidant exerting chemopreventive activity by reducing oxidative stress. This study was conducted to investigate the effects of pronyl-lysine supplementation on the formation of colonic precancerous lesions, circulatory lipid peroxidation, and enzymic antioxidant status in 1,2-dimethylhydrazine-induced colon carcinogenesis. Male Wistar rats were randomized into seven groups; group 1 was control rats, group 2 received pronyl-lysine (2 mg/kg body weight orally) everyday, rats in groups 3-7 were administered subcutaneous 1,2-dimethylhydrazine (20 mg/kg body weight) once a week for 15 consecutive weeks. In addition, group 4 (pre-initiation), 5 (initiation), 6 (post-initiation), and 7 (entire period) received pronyl-lysine (2 mg/kg body weight orally) everyday. At the end of 34 weeks, indicative markers of lipid peroxidation and changes in antioxidant defense system were measured in circulation. The results showed that 1,2-dimethylhydrazine significantly increased total aberrant crypt foci formation, total number of dysplastic foci, β-catenin accumulated crypts and proliferating cell nuclear antigen labeling index in the colon, and enhanced lipid peroxidation markers and decreased enzymic antioxidant activities in the plasma and erythrocyte lysate as compared with untreated controls. Pronyl-lysine supplementation significantly reversed the changes as compared with the rats treated with 1,2-dimethylhydrazine alone. The effect of pronyl-lysine was more pronounced when supplemented throughout the study period (group 7). These findings suggest that pronyl-lysine suppresses 1,2-dimethylhydrazine-induced colon carcinogenesis effectively.
