Department of Cell and Molecular Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7545, USA.
Am J Physiol Gastrointest Liver Physiol. 2011 Sep;301(3):G401-24. doi: 10.1152/ajpgi.00110.2011. Epub 2011 Jun 23.
Colorectal cancer (CRC) is the third most commonly diagnosed cancer in the United States, and, even though 5-15% of the total CRC cases can be attributed to individual genetic predisposition, environmental factors could be considered major factors in susceptibility to CRC. Lifestyle factors increasing the risks of CRC include elevated body mass index, obesity, and reduced physical activity. Additionally, a number of dietary elements have been associated with higher or lower incidence of CRC. In this context, it has been suggested that diets high in fruit and low in meat might have a protective effect, reducing the incidence of colorectal adenomas by modulating the composition of the normal nonpathogenic commensal microbiota. In addition, it has been demonstrated that changes in abundance of taxonomic groups have a profound impact on the gastrointestinal physiology, and an increasing number of studies are proposing that the microbiota mediates the generation of dietary factors triggering colon cancer. High-throughput sequencing and molecular taxonomic technologies are rapidly filling the knowledge gaps left by conventional microbiology techniques to obtain a comprehensive catalog of the human intestinal microbiota and their associated metabolic repertoire. The information provided by these studies will be essential to identify agents capable of modulating the massive amount of gut bacteria in safe noninvasive manners to prevent CRC. Probiotics, defined as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host" (219), are capable of transient modulation of the microbiota, and their beneficial effects include reinforcement of the natural defense mechanisms and protection against gastrointestinal disorders. Probiotics have been successfully used to manage infant diarrhea, food allergies, and inflammatory bowel disease; hence, the purpose of this review was to examine probiotic metabolic activities that may have an effect on the prevention of CRC by scavenging toxic compounds or preventing their generation in situ. Additionally, a brief consideration is given to safety evaluation and production methods in the context of probiotics efficacy.
结直肠癌（CRC）是美国第三大常见癌症，尽管总 CRC 病例的 5-15%可归因于个体遗传易感性，但环境因素可被认为是 CRC 易感性的主要因素。增加 CRC 风险的生活方式因素包括升高的体重指数、肥胖和减少的身体活动。此外，许多饮食因素与 CRC 的发生率较高或较低有关。在这种情况下，有人提出富含水果而低肉类的饮食可能具有保护作用，通过调节正常非致病性共生微生物群落的组成来降低结直肠腺瘤的发生率。此外，已经证明分类群丰度的变化对胃肠道生理学有深远的影响，越来越多的研究提出微生物群介导触发结肠癌的饮食因素的产生。高通量测序和分子分类学技术正在迅速填补常规微生物学技术留下的知识空白，以获得人类肠道微生物群及其相关代谢物谱的综合目录。这些研究提供的信息对于识别能够以安全非侵入性方式调节大量肠道细菌的制剂以预防 CRC 至关重要。益生菌被定义为“当以足够的量施用时，赋予宿主健康益处的活微生物”（219），能够暂时调节微生物群，其有益效果包括增强天然防御机制和防止胃肠道疾病。益生菌已成功用于治疗婴儿腹泻、食物过敏和炎症性肠病；因此，本综述的目的是检查益生菌的代谢活性，这些活性可能通过清除有毒化合物或防止其在原位生成来预防 CRC。此外，简要考虑了益生菌功效背景下的安全性评估和生产方法。
