Cancer is usually caused by mutation or activation of abnormal genes that control growth and cell division. Most of these abnormal cells do not cause cancer because normal cells usually exceed the abnormal. Also, the immune system recognizes and destroys most abnormal cells.
Many processes or exposures can increase the occurrence of abnormal cells. The precautions that minimize these exposures decrease the risk of cancer. Among the many potentially risky exposures are chemical exposures. Carcinogenic chemicals (carcinogens) can be ingested or generated by metabolic activity of microbes that live in the gastrointestinal tract.
It has been hypothesized that probiotic cultures might decrease the exposure to chemical carcinogens by:
- Detoxification of carcinogens ingested
- Altering the environment of the gut microbial populations and thereby decrease the metabolic activities of bacteria that may generate carcinogenic compounds
- Producing metabolic products (eg butyrate) which improve the capacity of a death when delula must die (a process known as apoptosis or programmed cell death)
- Producing compounds that inhibit the growth of tumor cells
- Stimulating the immune system to better defend against the proliferation of cancer cells.
Research suggests that the consumption of probiotic supplements can reduce cancer risk. Researchers tested the effect of consumption of fermented foods or probiotic supplements have found:
- A reduction in the incidence of chemical induced tumors in rats.
- A reduction in faecal enzyme activity (ß-glucuronidase, azoreductase, nitroreductase, and one-dehydrogenase 7) that are created may play a role in colon cancer in humans and animals.
- Degradation of nitrosamines.
- A softening of the mutagenic activity of substances tested in the laboratory.
- Prevention of damage to DNA in certain colonic cells.
- Enhance immune system function.