Articles for Our Patients ~ Vanessa Wada, MS, RD
The Probiotic Cancer Relationship
Source: Cancer-General • Author: Vanessa Wada, MS, RD • Language: ENG
One could only bet that the average consumer likely has minimal understanding of the use of probiotics. However, these organisms have demonstrated their potential in minimizing cancer treatment side effects and reducing cancer risk. By definition, probiotics are live microbial supplements that beneficially affect the host animal by improving its intestinal microbial balance.1 They are found in foods such as yogurt, cheese, miso, sauerkraut, pickles, artichokes, oats, and honey. They can also be purchased in isolated supplement form. These live microbes when ingested alter the chemistry of the gut by lowering the pH and altering the microflora. By doing this, lactic acid and other organic acids are produced which enable the change in pH.
Probiotics have a promising future in the prevention of several cancers. The most promising evidence is with regards to colon cancer. Probiotic intervention has been shown in studies to bind and deactivate carcinogens. They promote immune function, inhibit carcinogen-producing enzymes, and influence the overgrowth of flora in the gut. Since nearly 70% of the immune system is associated with the colon2, a probiotic immune boosting influence provides protection against harmful viral and bacterial strains and promotes tumor inhibition3.
Radiation induced enteritis and colitis is a severe complication for cancer patients as it can lead to diarrhea which can severely affect the hydration and nutritional status of a patient. Some studies have shown that using a Lactobacillus probiotic concoction can reduce the incidence and severity of diarrhea in these patients. Probiotics are an easy, safe, and cheap alternative to antibiotics in reducing the symptoms of radiation induced diarrhea4.
Another type of cancer which may be affected by probiotics is liver cancer. Hepatitis B infection is the main risk factor followed by exposure to aflatoxins, which are toxic compounds produced by fungi. They work by mutating DNA thereby promoting liver cancer. Although aflatoxins are present in the American diet, they are found at much higher levels in developing countries such as China. One study showed that the use of two different strains of the probiotic bacteria Lactobacillus rhamnosus two times a day for five weeks reduced the exposure of aflatoxins and carcinogens to the liver. These beneficial bacteria effectively bind to the toxins thereby preventing the toxins from mutating the liver DNA which reduce risk factors for liver cancer onset5.
Probiotics may also play a role in other cancers such as breast cancer and superficial bladder cancer prevention. Diets rich in cultured dairy products such as yogurt may inhibit the growth of breast cancer cells. Some studies have even shown that milk fermented by Lactobacillus helveticus stimulated the immune system in mice6. A different strain of bacteria, Lactobacillus casei, has been shown to decrease the recurrence of superficial bladder cancer. In this study, there was a 57% recurrence in patients receiving the probiotic after one year compared with 83% in patients who did not receive the probiotic. In another study, constant exposure to lactic acid bacteria such as Lactobacillus casei showed a significant reduction in bladder cancer risk7.
Probiotic-containing foods are fairly common in Japan and Europe but are slowly making their way in the United States. There is potential for these microbial creatures in cancer prevention, but further research needs to be conducted. Understanding the use of probiotics as a part of the whole food vs. the isolated product, obtaining a more thorough knowledge of its mechanism in the gut, and identifying the particular strains that have the largest beneficial impact in promoting health will be areas of future research and interest. And as long as these studies continue to provide positive outcomes, incorporating probiotics into the diet is a safe, easy, and cheap way to protect oneself from disease.
Vanessa Wada, M.S., RD
Clinical Dietitian/Community Nutrition
Pomona Valley Hospital Medical Center
1 Ferguson, L., and Philpott, M. (2007). Cancer Prevention by Dietary Bioactive Components that Target the Immune Response. Current Cancer Drug Targets. 7: 459-464
2 Saikali, J., Picard, C., Freitas, M., Holt, P. (2004). Fermented Milks, Probiotic Cultures, and Colon Cancer. Nutrition and Cancer. 49(1): 14-24
3 Sanders, M. (1999). Probiotics. Food Technology. 53(11):67-77
4 Delia, P., Sansotta, G., Donato, V., et al. (2007). Use of Probiotics for Prevention of Radiation-Induced Diarrhea. World J Gastroenterol 13(6): 912-915
5 El-Nezami, H., Polychronaki, N., Ma, J. et al. (2006) Probiotic Supplementation Reduces a Biomarker for Increased Risk of Liver Cancer in Young Men from Southern China. Am J Clin Nutr. (83):1199 –1203
6 LeBlanc, A., Matar, C., Perdigo, G. (2007). The Application of Probiotics in Cancer. British Journal of Nutrition. 98(1): S105–S110
7 Sleator, R., Hill, C. (2007). New Frontiers in Probiotic Research. Letters in Applied Microbiology. 46:143-147