Meat consumption linked to increased cancer risk

Scientists believe they have found an explanation of why eating red meat causes cancer, in the form of substances which damage DNA in the gut of meat eaters.

The finding lends weight to research published last year showing that the risk of bowel cancer is increased in people who eat red meat every day compared with those who eat it infrequently.


However the findings were disputed by the New Zealand meat industry. 

It was the largest study ever conducted into the health effects of meat-eating involving 500,000 Europeans in ten countries whose diets were monitored for five years.

The results showed that those who ate two portions a day of red meat - beef, lamb, pork, veal and their processed varieties ham and bacon - had a third higher risk of developing bowel cancer than those who ate one portion a week.

Eating white meat, such as chicken, had no effect.

Now scientists from the Medical Research Council, which part funded the earlier study, say they have found a possible biochemical mechanism to explain the earlier observation.

Samples taken from the digestive tracts of red meat eaters showed a higher level of DNA damage when compared with those from vegetarians at the MRC's Dunn Human Nutrition Unit in Cambridge.

The meat eaters produced substances called N-nitrosocompounds which are formed in the colon after eating red meat.

Earlier research carried out by Professor David Shuker at the Open University has shown that these compounds combine with DNA making it more likely to trigger mutations in cells leading to cancer.

"These combined discoveries have allowed us to link meat consumption to an increased risk of bowel cancer and may give us some clues about developing a screening test for very early changes related to the disease" Professor Shuker said.


A representative of the meat industry in New Zealand said the study was not realistic in showing people's normal food intake.


Fiona Carruthers, nutrition manager at New Zealand Beef and Lamb, said: "It doesn't reflect the way people eat. It is equivalent to eating 11 cottage pies a day."


She added that the researchers in last year's study had said further investigation was needed on their findings.


MRC chief executive, Professor Colin Blakemore, said: "Large bowel cancer is the second most common cancer in western countries, and nearly one million cases occur each year worldwide.

This latest study, together with the compelling epidemiological evidence published last year, is an important step towards understanding, and potentially preventing, this common disease."

Each year 35,000 people in Britain are diagnosed with bowel cancer, and 16,000 die of the disease.

"A third of all cancers are linked to what we eat and we must not underestimate the importance of a well-balanced diet in the prevention of bowel cancer" said a spokeswoman for charity Beating Bowel Cancer.

"This study adds further weight to previous evidence about the possible link between bowel cancer and a high consumption of red meat."

"As with all dietary advice, moderation is key, as we already know that a diet high in fat and red meat yet low in fibre, fruit and vegetables can increase the risk of developing this disease - currently the second biggest cause of cancer death in the UK."

- INDEPENDENT