Vitami.n C lowers bloo.d pressur.e

Editor’s note:   Many media outlets opt to avoid reporting this study.   We feel this is very important study and many consumers may find it useful.   Many epidemiologic studies have associated consumption of meat and milk with increased risk of cancer, but few provided any explanation why.   We have published part of the report, below is the complete report on the study.

Red meat, milk boost cancer risk, Aspirin may reduce it

People who use red meat and milk may not want to hear it that eating these foods increases risk of cancer. But a new study has already found a mechanism that explains why human consumption of red meat and milk products increases risk of cancerous tumors.

The study published online this week in advance of print publication in the Proceedings of the National Academy of Sciences (PNAS) found a molecule produced after consumption of these foods induces inflammation that boosts the cancer risk.

The molecule of concern, according to Ajit Varki, M.D., coauthor of the study, of the University of California, San Diego School of Medicine and colleagues, was a non-human cellular molecule called N-glycolylneuraminic acid (Neu5Gc).

Neu5Gc is a type of glycan, a sugary compound, which is not naturally present in human bodies.   But this molecule can be incorporated into human tissues as a result of eating red meat.   When it gets into human tissues, the body develops anti-Neu5Gc antibodies, an immune response that could lead to chronic inflammation and boost cancer growth.

"We've shown that tumor tissues contain much more Neu5Gc than is usually found in normal human tissues," said Varki. "We therefore surmised that Neu5Gc must somehow benefit tumors."

Chronic inflammation has been known for some time to actually stimulate cancer, Varki explained. But the researchers wondered why tumors containing the non-human molecule grew even in the presence of Neu5Gc antibodies.

"The paradox of Neu5Gc accumulating in human tumors in the face of circulating antibodies suggested that a low-grade, chronic inflammation actually facilitated the tumor growth, so we set out to study that hypothesis," said co-author Nissi M.Varki, M.D. at UCSD.

To test how Neu5Gc affect cancer, the researchers induced in mice tumors containing Neu5Gc and then administered ant-Neu5Gc antibodies to one group of mice and left another group mice untreated.

They found in the mice treated with antibodies, which is equavalent to being treated with ingested red meat and milk, inflammation was induced and the tumors grew faster compared to mice that were untreated.   In untreated mice, the tumors were less aggressive.

Prvious studies by other researchers have shown that humans who take non-steroidal anti-inflammatory drugs (commonly known as NSAIDs) have a reduced risk of cancer., suggesting that inflammation is involved in carcinogenesis. But the current study provided one mechanism to explain why.

To further test if Anti-inflammatory drugs may affect the effect of Neu5Gc, interestingly the researchers observed the mice treated with anti-Neu5Gc antibodies and then treated with an NSAID had their tumors reduced in size.

"Taken together, our data indicate that chronic inflammation results from interaction of Neu5Gc accumulated in our bodies from eating red meat with the antibodies that circulate as an immune response to this non-human molecule – and this may contribute to cancer risk," said Varki.

The study was supported in part by a grant from the National Cancer Institute, of the National Institutes of Health.

A study published in Cancer Epidemiology Biomarkers and Prevention. 2008;17:3098-3107 found that those who ate the most red meat had a 67 percent higher risk of colorectal cancer, regardless of any genetic factors they may have.   The increased risk was even greater in those who had specific genes compared to people who did not eat meat.

So what is the message?   Eating red meat and milk boosts cancer risk. And taking anti-inflammation drugs reduces the risk.