The study analyzed 3627 cancer patients - their dietary patterns and family history. Patients who were originally from Bengal and eastern part of India were mainly red meat-eaters and those from other parts of India were mainly vegetarians. "The incidence of colon cancer was 8.22% (298 patients) which is alarmingly high. Ninety-four percent of them consumed red meat whereas only 6% were purely vegetarians. Ninety nine percent of the colon cancer patients were permanent residents of Bengal whereas just 1% was from other parts of the country. Those with colon cancer had a history of red meat intake which was greater than 500 gm/week," said Ashish Mukhopadhyay of NSCBCRI.
With processed meat consumption on the rise, more could be affected, feared experts. Preservatives like sodium phosphate and nitrate used in processed meat have been proved to be carcinogenic. Chemicals of the benzyne group and nitroso urea also acted as carcinogenic agents and were found even in processed lean meat like chicken. These have been found to damage the cells that line the bowel, so other cells in the bowel lining have to replicate more in order to heal. And it's this 'extra' replication that can increase the chance of errors developing in the cells' DNA - the first step on the road to cancer.
Epidemiological studies shows that there is co-relation of meat consumption and cancer of colorectal region. It has been shown that consumption of 80gm/day red meat (Beef, Lamb & Pork) or processed meat (Ham, Salami, Bacon) may increase colorectal cancer risk by 25% and 67% respectively. Several biological mechanisms are responsible for this. These include the influence of meat and fat consumption on the production and metabolism of bile salts and bile acids by gut flora.
Incidence of colon cancer is less than 1% in the south and west. Red meat and smoking were the reasons, said Gautam Mukhopadhyay. "Regular consumption of red meat is certainly a cause. But you must consume it in a substantial quantity and over a period of time. In India, the eastern region consumes it more than the rest of the country. This is why we come across more colorectal cancer patients here," said Mukhopadhyay. Colon cancer is third commonest in eastern part of India.