This information sheet is based on research evidence that has been written for the general public and used by the NZ Cancer Society.
Red meats including beef, lamb and pork, are a valuable source of a number of different nutrients, especially protein, iron, zinc and vitamin B12. However, research shows bowel cancer is more common in people who eat large amounts of red and processed meats than people who eat smaller amounts.
Chemicals have been found in red and processed meat that may explain the increased cancer risk. One chemical is haem, which when broken down in the bowel seem to damage nearby cells, making cancer more likely to develop.
Cooking meat at a very high temperature and burning or charring meats creates chemicals called heterocyclicamines, which may contribute to the risk of stomach cancer and can damage our cells, making them more likely to become cancerous. When barbequing, grilling or pan frying meat, try not to overcook it and avoid eating any charred parts.
Processed meats, including sausages, frankfurters, salami, ham, bacon, pastrami and corned meats are more strongly linked to bowel cancer than fresh red meats. Processed meats usually contain high levels of salt and fat, have added nitrogen-based preservatives and are often smoked. All of these are likely to increase the risk of cancer.
Added salt and salt preserved foods and smoked foods may increase the risk of stomach cancer but do not appear to be related to bowel cancer.
Nitrogen-based preservatives seem to be the main reason for the increased risk of bowel cancer if eaten regularly.
Red and processed meats may also affect cancer risk because of the fat content. Fat can contribute to weight gain and being overweight or obese is one of the strongest risks for a number of different cancers.
It is recommended you only eat small amounts of red meat, less than 500g per week. This is about half a cup of mince, two small chops or two slices of roast meat (would fit into the palm of your hand). Choose lean meat and cut off any fat then grill or casserole without adding extra fat or oil.
It is recommended you eat very little or no processed meats.
Choose other protein foods such as chicken, fish, eggs or legumes such as lentils, chick peas, baked beans, red kidney beans etc. to replace red and processed meats in meals.