Gut bacteria may help prevent cancer: study

Various types of intestinal bacteria may not only play a role in preventing obesity, but also potentially be used to reduce the risk for some types of cancer, new research has found.

The research offers evidence that anti-inflammatory "health beneficial" gut bacteria can slow or stop the development of some types of cancer, researchers said.

Ultimately, doctors might be able to reduce a person's risk for cancer by analysing 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, they said.

"It is not invasive and rather easy to do," said Robert Schiestl, professor at University of California, Los Angeles (UCLA) and the study's senior author.

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," said Schiestl.In the 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 ageing 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 leukaemia, 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. Researchers showed that in the mice with more of the beneficial bacteria, the lymphoma took significantly longer to form.