http___metro-portal.hr_crveno-meso-sadrzi-stetni-secer_89423_1.xml
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For years, epidemiological studies have established the link between certain cancers and red meat. In a recent study, researchers at the University of California, San Diego School of Medicine have linked tumor formation to a specific sugar molecule. The study was published online Monday in the early edition of the Proceedings of the National Academy of Sciences. In trying to explain why red meat consumption is observed to increase cancer risk, researchers have tried to determine molecules that are specific to red meat. Previous studies have shown that red meat can cause damage to the DNA in colon cells, but what molecule is causing the damage? Several molecules have been proposed, including N-nitroso compounds (NOCs) , which are both produced in the body and present in certain foods. In a recent prospective study, dietary NOCs were implicated in increased incidents of gastrointestinal cancer. In the present study, researchers honed in on the molecule N-glycolylneuraminic acid (Neu5Gc), a non-human sugar present in red meat. Researchers found that red meats (including beef, lamb, and pork) are rich in Neu5Gc, and that once consumed, the molecule is bioavailable. The researchers hypothesized that the immune response to the foreign molecule could lead to chronic inflammation, and eventually cancer. To test this theory, the team genetically engineered “human-like” mice that lacked Neu5Gc. When these mice were fed Neu5Gc, they developed evidence of systemic inflammation. Also, the Neu5Gc-deficient mice had a much higher incidence of tumor formation when fed Neu5Gc, with the formation increasing fivefold. Researchers are understandably excited about this direct evidence of tumor formation. “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,” said lead author Ajit Varki, in a statement. Mimicking this situation is not the same as proving it in humans, but the researchers explain that their findings could also explain other diseases. “[O]n a more general note, 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.” said Varki. Red meat provides many vital nutrients such as iron, protein and vitamin B12, and the researchers are not advocating for the removal of red meat completely. The authors are hopeful that a more complete understanding of how red meat affects the human body will lead to a solution. “We hope that our work will eventually lead the way to practical solutions for this catch-22,” Varki concludes.
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Crveno meso sadrži štetni šećer? Novi nalazi sugeriraju kako je šećer Neu5Gc prisutan u crvenom mesu uzrok povećanja rizika za zdravlje Meso je već duže vrijeme na nišanu nutricionista koji preporučuju smanjivanje upotrebe crvenog mesa, što zapravo i ne čudi previše kad se znaju uvjeti u kojima se uzgajaju svinje i krave i što se sve u tom mesu može pronaći. Stručni časopis Proceedings of the National Academy of Sciences piše kako su neka ranija istraživanja povezala pretjeranu konzumaciju crvenog mesa s većim rizikom obolijevanja od raka. Novi eksperimenti provedeni na miševima su pokazali kako tip šećera prisutan u crvenom mesu nakon akumulacije u organizmu dovodi do proizvodnje anti-Neu5Gc antitijela. Riječ je o antitijelima koja izazivaju upalne procese te na dugi rok mogu dovesti do nastanka tumora, pojašnjavaju istraživači.