Cancer-preventing attributes of probiotics: an update

Abstract

Cancer is a serious global public health problem. Cancer incidence and mortality have been steadily rising throughout the past century in most places of the world. There are several epidemiological evidences that support a protective role of probiotics against cancer. Lactic acid bacteria and their probioactive cellular substances exert many beneficial effects in the gastrointestinal tract, and also release various enzymes into the intestinal lumen and exert potential synergistic (LAB) effects on digestion and alleviate symptoms of intestinal malabsorption. Consumption of fermented dairy products with LAB may elicit anti-tumor effects. These effects are attributed to the inhibition of mutagenic activity, the decrease in several enzymes implicated in the generation of carcinogens, mutagens, or tumor-promoting agents, suppression of tumors, and epidemiology correlating dietary regimes and cancer. Specific cellular components in lactic acid bacteria seem to induce strong adjuvant effects including modulation of cell-mediated immune responses, activation of the reticulo-endothelial system, augmentation of cytokine pathways, and regulation of interleukins and tumor necrosis factors. Studies on the effect of probiotic consumption on cancer appear promising, since recent in vitro and in vivo studies have indicated that probiotic bacteria might reduce the risk, incidence and number of tumors of the colon, liver and bladder. The protective effect against cancer development may be ascribed to binding of mutagens by intestinal bacteria, may suppress the growth of bacteria that convert procarcinogens into carcinogens, thereby reducing the amount of carcinogens in the intestine, reduction of the enzymes beta-glucuronidase and beta-glucosidase and deconjugation of bile acids, or merely by enhancing the immune system of the host. There are isolated reports citing that administration of LAB results in increased activity of anti-oxidative enzymes or by modulating circulatory oxidative stress that protects cells against carcinogen-induced damage. These include glutathione-S-transferase, glutathione, glutathione reductase, glutathione peroxidase, superoxide dismutase and catalase. However, there is no direct experimental evidence for cancer suppression in human subjects as a result of the consumption of probiotic cultures in fermented or unfermented dairy products, but there is a wealth of indirect evidence based largely on laboratory studies.

Effects of Lactobacillus salivarius Ren on cancer prevention and intestinal microbiota in 1, 2-dimethylhydrazine-induced rat model

“…and Clostridium sp. have been implicated in the pathogenesis of CRC (Sobhani et al, 2011) while numerous lactic acid bacterias have been shown to possess cancer-preventing attributes (Kumar et al, 2010). Wei et al (2010) also proved that Ruminococcus-like and Allobaculum-like bacteria were identified as crucial variables for discrimination of DMH-treated rats from controls.…”

“…and Clostridium sp. have been implicated in the pathogenesis of CRC (Sobhani et al, 2011), while some lactic acid bacteria have been shown to possess cancer-preventing attributes (Kumar et al, 2010).…”

Anticarcinogenecity of microbiota and probiotics in breast cancer

“…Antioxidants produced by Streptococcus thermophilus are linked with decreased DNA damage, and thus, cancer by neutralizing reactive oxygen species (ROS). [18] In healthy breast, Lactococcus and Streptococcus bacteria are more prevalent because bacteria were thought to have anticancer property. Bacteria from cancerous females were grown on human breast cancer cells to check their ability of triggering DNA damage.…”

“…[16] Probiotics means "for life" or an antonym for antibiotics [17] , when taken in sufficient amount, viable and non-disease causing microorganisms (bacteria or yeasts) impart health benefits via preclusion (prevention) and cure of particular pathological disorders or can lessen the possibility of disease to host are referred as probiotics. [18,19] Various microorganisms are used as probiotics especially lactic acid bacteria (LAB). LAB includes most of Lactobacillus species, some species of Bifidobacteria, Enterococcus, and Streptococcus.…”

Fermentation Technology in the Development of Functional Foods for Human Health: Where We Should Head

“…Probiotic have been considered Generally Recognized As Safe for human consumption and known to exhibit various health beneficial effects i.e. anti-cancer, immunomodulatory, anti-oxidant, cardio protective and anti-obese/ diabetic [7][8][9]. There are various mechanisms have been proposed for the bioactivity of the probiotics on human health, and one of them is the probiotics mediated production of bioactive components during fermentation process of foods ( Figure 1).…”