Health experts have known for years that the consumption of red meat raises a person's cancer risk. But what they haven't known is why. Until now. Contrary to what some researchers previously thought, it's not the fat in red meat that increases cancer risk. Nor is it the cholesterol. And it's not the way we grill our burgers and steak. It's the sugar.

Researchers at the University of California, San Diego recently revealed in a study that the reason red meat is linked to higher cancer risk is that it contains a sugar molecule — specifically Neu5Gc — that is not natural in the human body. When our immune system spots this sugar molecule, it attacks it, and it is the inflammation from this attack that over time and continued exposure, raises a person's lifetime risk for cancer.

What's more, Neu5Gc is found in beef, pork, lamb and bison. But it's not found in chicken or fish — two sources of meat that are not linked to an increased cancer risk. It is, however found in fish eggs (caviar,) as well as whole milk and certain cheeses.

Previously, health experts believed that it was the grilling of red meat that led to the increase in cancer risk. But researchers couldn't understand why grilling chicken and fish did not also lead to an increased risk. Now, they have a better understanding of why.

Dr. Ajit Varki, the lead author of the study, said the Neu5Gc phenomenon is unprecedented. Varki said Neu5Gc plays the role of “gasoline on the fire” — it does not directly cause cancer, but it does boost the risk for the disease. 

So, should you stop eating red meat? Varki doesn't think so. He recommends using moderation when choosing red meat and limiting consumption to two or three servings per week. 

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

Related on MNN: