Probiotics and Cancer Prevention
You may have heard that the human body contains more bacteria than cells…and it’s true! Our bodies are home to a vast, amazing ecosystem of bacteria—tens of trillions of teeny tiny microbes that are involved in nearly every aspect of our health.
These beneficial bacteria—better known as probiotics—prevent gastrointestinal issues and improve overall digestive function; ease inflammatory conditions such as autoimmune diseases; and support urinary and vaginal health. They’ve also been shown to lower LDL cholesterol, manage healthy weight, enhance brain function, assist in the manufacture and absorption of various nutrients; and boost overall immunity. In fact, up to 80% of our immune strength comes courtesy of the beneficial bacteria in the gut. (This amounts to about 10 pounds of microorganisms!)
Probiotics and colorectal cancer
And there’s another area where research is really starting to show the incredible potential of probiotics—cancer prevention. Right now, the greatest promise may lie with colorectal cancer.
Considering most of the beneficial bacteria in our bodies reside in the gut, it should come as no surprise that these friendly microbes can play a part in reducing the risk of colorectal cancer.
In a study published in 2017, researchers found that adding certain probiotics could become a new preventive or therapeutic strategy for inflammatory bowel disease patients who are at higher risk for colorectal cancer.
This experiment used mice that were deficient in histidine decarboxylase (HDC), an enzyme that converts the compound histidine to histamine. Histamine is important in the regulation of several body functions, including gastric acid secretion and immune response.
Some of the mice were given the probiotic Lactobacillus reuteri 6475, which has the ability to convert histidine to histamine. The rest received placebo. The mice were induced to develop colon cancer. Fifteen weeks later they were sacrificed and had their tissues tested.
The researchers found that the mice that received probiotics had increased HDC and histamine in their colons. And compared to the mice in the control group, they had fewer and smaller tumors in their colons.
In another study, researchers concluded 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” which then get eliminated from the body. They go on to say that probiotics may also “suppress the growth of bacteria that convert procarcinogens into carcinogens, thereby reducing the amount of carcinogens in the intestine” or simply prevent cancer “merely by enhancing the immune system of the host.”
Prebiotics Enhance Probiotic Benefits
Using prebiotics along with probiotics may confer even greater protection against colon cancer.
Prebiotics are the non-digestible food (insoluble fiber) that probiotics feed on. Beneficial bacteria “digest” this prebiotic fiber through the process of fermentation. In the process, they produce extremely important compounds called short-chain fatty acids (SFCAs)—two of which are butyrate and propionate.
Butyrate, in particular, is a main source of energy for the cells that line the gut walls. They help to strengthen those walls and prevent intestinal problems like leaky gut syndrome, irritable bowel, Crohn’s disease, and other inflammatory conditions.
Butyrate also controls the expression of certain genes and has been found to turn off the genetic “switch” that initiates the development of colon cancer cells. Simply put, butyrate is the reason why high-fiber foods are helpful in the prevention of colorectal cancer. In fact, a 2013 study concluded that, “a high-fiber dietary pattern and subsequent consistent production of SCFAs and healthy gut microbiota are associated with a reduced risk of A-CRA [advanced colorectal adenoma—a precursor to malignancy].”
While research is still preliminary, there’s potential for probiotics to play a role in breast cancer prevention as well.
Just as the gut has a unique microbiome, so do the breasts. It has been discovered that women with breast cancer have higher levels of Enterobacteriaceae, Staphylococcus, and Bacillus strains of bacteria compared to women without the disease. Enterobacteriaceae is the family of bacteria that includes E.coli—the common pathogenic strain associated with hospital infections.
On the other hand, the probiotic strains Lactobacillus and Lactococcus are more common in healthy breast tissue. Stay tuned…I’m sure exciting research is on the horizon!
Nourish Your Gut
I can confidently say, if there’s one thing you can do to improve the health of every square inch of your body, it’s to nourish your microbiome through diet and supplementation.
First, add a wide variety of probiotic-rich fermented foods to your diet. Sauerkraut, yogurt, kefir, kombucha, and kimchi are perhaps the most well known, but some others include miso, tempeh, natto, sourdough bread, kvass, and any kind of pickled vegetable.
Then, for definitive assurance that you’re providing your body a healthy dose of beneficial bacteria daily, I recommend taking a probiotic supplement.
When choosing a probiotic, it is important to find a product that has enterically coated or microencapsulated bacteria. This special technology allows these beneficial bacteria to survive as they pass through the acidic environment of your stomach. Without an enteric coating or microencapsulation, most probiotics die en route to your lower gut, where they do their best work.
You should also look for products that contain a blend of different strains of bacteria, with at least 10 billion colony forming units (CFUs) per dose. (This refers to the number of live and active bacteria found in each serving.)
Finally, be sure to include prebiotics to support the health of the probiotics and encourage robust SCFA production. You can get prebiotics by eating high-fiber foods such as onions, leeks, garlic, and asparagus, or you can look for a probiotic supplement that includes prebiotics in the formula.
For best results, follow the dosage and storage instructions listed on your supplement label. Some probiotics (usually freeze-dried organisms sold in capsule form) can be kept in a cool, dry place like a kitchen pantry. Other brands may need to be refrigerated.
- New research on probiotics in the prevention and treatment of colon cancer. Elsevier press release. Last accessed June 15, 2018.
- Kumar M, et al. Cancer-preventing attributes of probiotics: an update. Int J Food Sci Nutr. 2010 Aug;61(5):473-96. Last accessed June 15, 2018.
- Blouin HM, et al. Butyrate elicits a metabolic switch in human colon cancer cells by targeting the pyruvate dehydrogenase complex. Int J Cancer. 2011 Jun 1;128(11):2591-601. Last accessed June 15, 2018.
- Chen HM, et al. Decreased dietary fiber intake and structural alteration of gut microbiota in patients with advanced colorectal adenoma. Am J Clin Nutr. 2013 May;97(5):1044-52. Last accessed June 15, 2018.
- Brubaker J. The breast microbiome: a role for probiotics in breast cancer prevention. American Society for Microbiology blog post. 2017 July 8. Last accessed June 15, 2018.