Intestinal bacteria can be used to reduce cancer risk, reveals UCLA study

Researchers have shown that various types of intestinal bacteria might be factors in both causing and preventing obesity, and in other conditions and diseases. Now, a UCLA study suggests that it could also potentially be used to reduce the risk for some types of cancer.

The research, published online April 13 in the peer-reviewed journal PLOS ONE, offers evidence that anti-inflammatory "health beneficial" gut bacteria can slow or stop the development of some types of cancer.

Ultimately, doctors might be able to reduce a person's risk for cancer by analyzing the levels and types of intestinal bacteria in the body, and then prescribing probiotics to replace or bolster the amount of bacteria with anti-inflammatory properties, said Robert Schiestl, professor of pathology, environmental health sciences and radiation oncology at UCLA and the study's senior author.

"It is not invasive and rather easy to do," he said.

Over millions of years, gut bacteria have evolved into both good and bad types: The good ones have anti-inflammatory properties and the bad ones promote inflammation. The human body typically contains about 10 trillion bacterial cells, compared with only 1 trillion human cells.

Schiestl and his colleagues isolated a bacterium called Lactobacillus johnsonii 456, which is the most abundant of the beneficial bacteria, and which has some pretty useful applications outside of medicine. "Since it is a Lactobacillus strain, it makes excellent yogurt, kefir, kombucha and sauerkraut."

In the UCLA study the bacterium reduced gene damage and significantly reduced inflammation — a critical goal because inflammation plays a key role in many diseases, including cancer, neurodegenerative diseases, heart disease, arthritis and lupus, and in the aging process.

Previous research led by Schiestl presented the first evidence of a relationship between intestinal microbiota and the onset of lymphoma, a cancer that originates in the immune system. The new study explains how this microbiota might delay the onset of cancer, and suggests that probiotic supplements could help keep cancer from forming.

For both studies, Schiestl and his team used mice that had mutations in a gene called ATM, which made them susceptible to a neurologic disorder called ataxia telangiectasia. The disorder, which affects 1 in 100,000 people, is associated with a high incidence of leukemia, lymphomas and other cancers.

The mice were divided into two groups — one that was given only anti-inflammatory bacteria and the other that received a mix of inflammatory and anti-inflammatory microbes that typically co-exist in the intestines.

In the Cancer Research paper, Schiestl and his team showed that in the mice with more of the beneficial bacteria, the lymphoma took significantly longer to form.

In the new study, the researchers analyzed the metabolites — molecules produced by the gut's natural metabolic action — in the mice's urine and feces. The scientists were surprised to find that the mice that were receiving only the beneficial microbiota produced metabolites that are known to prevent cancer. Those mice also had more efficient fat and oxidative metabolism, which the researchers believe might also lower the risk for cancer.

Intestinal bacteria can be used to reduce cancer risk, reveals UCLA study: Researchers have shown that various types of intestinal bacteria might be factors in both causing and preventing obesity, and in other conditions and diseases. Now, a UCLA study suggests that it could also potentially be used to reduce the risk for some types of cancer.