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Experts Cast Doubt on the Meat and Cancer Hypothesis

Wednesday, August 6, 2008

        Columbus, Ohio, August 6, 2008 - A panel of government, university and industry experts speaking at a leading food safety conference today cast serious doubt on widely reported claims of a meat and cancer connection. 

            "All too often, claims that meat is linked to cancer are made as if they are proven fact.  But today's panel presented compelling evidence the 'conventional wisdom' is not always current or accurate," said AMI Foundation President Randy Huffman, Ph.D.  The timely symposium was held at the International Association for Food Protection Annual Meeting in Columbus, Ohio.

            David Klurfeld, Ph.D., national program leader in human nutrition at the U.S. Department of Agriculture (USDA) Agricultural Research Service, provided an extensive critique of the 2007 World Cancer Research Fund (WCRF) Report, released in the U.S. by its affiliate, the American Institute for Cancer Research (AICR).  While AICR made dramatic claims in a November 2007 press release that its report found a "convincing link" between red and processed meat and colorectal cancer, Klurfeld noted that a careful read of the 500-page report and its companion 2,334-page systematic literature review shows that the report does not support the press release's dire warnings.

           According to Klurfeld, the systematic literature review said that, "Overall, mechanisms explaining the data linking meat intake and colorectal cancer are far from plausible biological mechanisms."  He also said the literature review found a statistically significant 26 percent protective effect against rectal cancer for the highest meat consumption level - a finding not referenced in the final WCRF report or the press release.

            "While few people likely will tackle the 2,334-page literature review after reading a 500-page summary of findings, those who do will find some critical information that was disregarded and contradicted in the report's summary," Klurfeld said.  He expressed frustration that the group's press release reflected so poorly what was actually in the report and literature review. 

            In a dramatic presentation about the state of the science on sodium nitrite safety and positive health benefits, Nathan Bryan, Ph.D., of the University of Texas Houston Institute of Molecular Medicine, told attendees that many members of the media, the public and the scientific community have outdated notions about sodium nitrite's safety.

            "The public perception is that nitrite and nitrate are carcinogens but they are not," Bryan said.  "Many studies implicating nitrite and nitrate in cancer are based on very weak epidemiological data. If nitrite and nitrate were harmful to us, then we would not be advised to eat green leafy vegetables or swallow our own saliva, which is enriched in nitrate and nitrite."

            Bryan explained that fruits and vegetables contribute far more nitrite and nitrate to human daily intake than cured meats.  For example, a person would derive 100 times as much nitrite from the modern elixir pomegranate juice as they do from a hot dog.

            He also detailed the many cardiovascular and other health benefits that are now being associated with nitrite.  According to Bryan, nitrite can prevent injury from a heart attack and act as an active source of nitric oxide within the body.  Furthermore, Tibetan natives living at high altitudes have 100 times more nitrite in their blood than people living at sea level.  Increasing nitrite availability appears to be a natural, adaptive physiological response to low oxygen. 

            In addition, he said that preliminary research at his university is showing that when nitrite has been applied directly to tumor cell lines, it did not promote tumor growth.  And when ascorbate (Vitamin C) is added along with the nitrite, cell growth is inhibited (ascorbate is routinely added along with nitrite in cured meats).

            Bryan's compelling presentation mirrors findings at the National Institutes of Health in Bethesda, Md., where Dr. Mark Gladwin has also published findings about nitrite's value as a medical treatment.

            Equally important is the very reason that nitrite is added to cured meats:  food safety.  Nitrite prevents growth of Clostridium botulinum, which causes the disease botulism.  More recently, researchers have also documented that nitrite inhibits the growth of Listeria monocytogenes if it is present, and lower levels mean lower risk to people if it were consumed.

            James Coughlin, Ph.D., an independent, expert food toxicologist with more than 30 years of experience with nitrite, also discussed standards of scientific evidence that should be carefully employed when assessing the results of epidemiology and toxicology studies of meats and nitrite.  Arthur Miller, Ph.D., senior managing scientist at Exponent, detailed the state of the science on heterocyclic and polyaromatic amine formation during grilling. 

            "If someone today said the world was flat, we'd laugh because that's such an uninformed and disproved hypothesis," Huffman said. "We need to put some of our notions about meat and cancer, nitrite risks and other issues into that same mythological category.  The public has been saturated for so long with these claims that they've been incorporated into our belief systems, but just as the world isn’t flat, meat cured with sodium nitrite is both safe and nutritious.”

            Huffman underscored that fresh and processed meats offer important nutrition benefits including protein, essential vitamins, minerals, protein and amino acids.  Eating meat also contributes a feeling of satiety, and new research shows that low-carbohydrate/high protein diets are more effective in weight control than simply reducing calories.

            To view these presentations, go to:  http://www.foodprotection.org/.




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