The World Health Organization has determined that dietary factors account for at least 30 percent of all cancers in Western countries and up to 20 percent in developing countries. When scientists started to search for links between food and cancer, one of the most noticeable findings was that people who avoided meat were much less likely to develop the disease. Large investigations conducted in different parts of the world showed that vegetarians were about 40 percent less likely to develop cancer compared to meat consumers.
A number of theses have been penned to explain the link between meat consumption and cancer risk. First, meat is devoid of fibre and other nutrients that have a protective effect. Meat also contains animal protein, saturated fat, and, in some cases, carcinogenic compounds such as heterocyclic amines (HCA) and polycyclic aromatic hydrocarbons (PAH) formed during the processing or cooking of meat. HCAs, formed as meat is cooked at high temperatures, and PAHs, formed during the burning of organic substances, are believed to increase cancer risk. In addition, the high fat content of meat and other animal products increases hormone production, thus increasing the risk of hormone-related cancers such as breast and prostate cancer.
Meat may affect cancer risk because of chemicals formed during digestion that have been found to damage the cells that line the bowel. Other likely factors include the fat content, and the way it is processed or cooked or because big meat eaters miss out on other protective foods such as fruit and vegetables or wholegrain cereals.
Carcinogenic Compounds in Cooked Meat
- Heterocyclic Amines or HCAs, a family of mutagenic compounds, are produced during the cooking process of many animal products, including chicken, beef, pork, and fish. Even meat that is cooked under normal grilling, frying, or oven-broiling may contain significant quantities of these mutagens. The longer and hotter the meat is cooked, the more these compounds form. In some studies, grilled chicken has formed higher concentrations of these cancer-causing substances than other types of cooked meat.
- Grilling or broiling meat over a direct flame results in fat dropping on the hot fire and the production of polycyclic aromatic hydrocarbon-containing flames. Polycyclic aromatic hydrocarbons (PAHs) adhere to the surface of food and the more intense the heat, the more PAHs are present. They are widely believed to play a significant role in human cancers. A fairly consistent association between grilled or broiled, but not fried, meat consumption and stomach cancer implies that dietary exposure to PAHs may play a role in the development of stomach cancer in humans.
How much eat should be consumed then?
According to the Cancer Council, a moderate intake of meat is 65-100g of cooked red meat, 3-4 times a week. It further suggests that people limit or avoid eating processed meats
, which are high in fat, salt and nitrates. Because of the high fat and salt content of processed meats, they should be eaten occasionally.
Try to choose lean cuts of meat or chicken, have more fish and make sure you eat plenty of plant-based foods such as fruit, vegetables and wholegrain cereals
Guidelines on meat and low-fat cooking methods
- Fill half your dinner plate with vegetables and don’t think of meat as the main part of the meal.
- Include at least three different coloured vegetables with your main meal.
- Have some legume-based meals each week. Legumes include lentils, chickpeas, baked beans and red kidney beans. There are many types of dried peas and beans, which can be added to casseroles, soups or salads.
- Buy lean cuts of meat - with the fat trimmed off and little marbling of fat.
- Trim any visible fat off the meat before you cook it.
- Choose chicken pieces without the skin or remove skin before cooking.
- Canned fish like tuna and salmon make an easy sandwich with salad.
- Adapt your recipes to include more vegetables.
- For stir-fries, reduce the amount of meat and add extra vegetables.