Non-human sugar in red meat may promote cancer

Washington, Dec 30  A team lead by an Indian-origin researcher at the University of California, San Diego, has found that a non-human sugar present in red meat promotes inflammation and cancer progression in rodents.

During the study, the scientists fed the sugar molecule known as Neu5Gc to mice which significantly promoted spontaneous cancers.

The study did not involve exposure to carcinogens or artificially inducing cancers, further implicating Neu5Gc as a key link between red meat consumption and cancer.

"Until now, all of our evidence linking Neu5Gc to cancer was circumstantial or indirectly predicted from somewhat artificial experimental set ups," said principal investigator Ajit Varki, distinguished professor of medicine and cellular and molecular medicine at University of California, San Diego.

"This is the first time we have directly shown that mimicking the exact situation in humans - feeding non-human Neu5Gc and inducing anti-Neu5Gc antibodies - increases spontaneous cancers in mice," Varki noted.

Neu5Gc is found naturally in most mammals but not in humans.

Varki's team found that red meats (beef, pork and lamb) are rich in Neu5Gc, affirming that foods of mammalian origin such as these are the primary sources of Neu5Gc in the human diet.

The molecule was found to be bio-available too, meaning it can be distributed to tissues throughout the body via the bloodstream.

The researchers had previously discovered that animal Neu5Gc can be absorbed into human tissues.

In this study, they hypothesised that eating red meat could lead to inflammation if the body's immune system is constantly generating antibodies against consumed animal Neu5Gc, a foreign molecule.

"This work may also help explain potential connections of red meat consumption to other diseases exacerbated by chronic inflammation, such as atherosclerosis and type 2 diabetes," Varki noted.

"Of course, moderate amounts of red meat can be a source of good nutrition for young people. We hope that our work will eventually lead the way to practical solutions for this catch-22 situation," the authors concluded.

The study was published in the journal Proceedings of the National Academy of Sciences.