Processed meats increase cancer and heart deaths

  • 7 Mar 2013
  • Reading time 4 mins
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A huge study of half a million men and women finds that two hamburgers a week, or four sausages, significantly increases your risk of dying younger from cancer or heart disease.

This European study finds that processed meat predicts an increased risk for cardiovascular disease and cancer even when you control for variables, such as high meat eaters having a worse diet and lifestyle. The lead author of the study, Prof Sabine Rohrmann, from the University of Zurich, says, "Risks of dying earlier from cancer and cardiovascular disease also increased with the amount of processed meat eaten. Overall, we estimate that 3% of premature deaths each year could be prevented if people ate less than 20g processed meat per day." 20g is about a tablespoon. So that's a limit of 140 grams a week. A hamburger weighs 100 grams. A sausage weighs 56 grams. So that’s a max of one and half hamburgers, of three sausages a week. The strongest, and most consistent health risk link is to cancer.

Compounds found in these meats (N-nitroso) damage DNA, and the high cooking temperatures may also produce heterocyclic amines (HCAs) and acrylamides, which are known carcinogens. According to researchers at the University of Hawaii, in a study involving almost 200,000 people followed over seven years, eating too many hot dogs, sausages and other processed meats can also increase the risk of developing pancreatic cancer. Those who ate the least processed meat cut their risk of developing pancreatic cancer by almost half compared to those with the highest intake.

People who ate a lot of pork and red meat also increased their pancreatic cancer risk by around 50 per cent, compared to those who ate less meat. There was no increased risk linked to eating poultry, fish or dairy products. Dr Ute Nothlings of the Cancer Research Center at the University of Hawaii, who led the research, suggests that the link could be due to the chemical reactions that occur during the preparation of processed meats, rather than its fat or cholesterol levels. He said such reactions could produce carcinogenic chemicals. It may not be meat, per se, that increases the risk of cancer but what’s added to it and what we do with it.

Generally, studies on Americans show the strongest association between meat consumption and cancer risk. One possible reason for this could be that animals in the EU are not given growth hormones, which are widely used for animals in the US. They found that meat consumption in itself didn’t increase kidney cancer risk except in those eating lots of fried or sautéed meat. The fat in meat, if burned, generates oxidants and carcinogens. Grilling, barbecuing and frying meat all increase the risk, particularly of stomach and colorectal cancer. It is not surprising to find that a diet of cooked meat, high in protein and fat, and low in fibre, together with carcinogens created from burning, creates havoc with the digestive tract.

All this explains the link with cancer of the stomach, colon, rectum, pancreas (the organ responsible for digesting protein) and kidneys (the organ that has to eliminate the breakdown products of protein and other toxins). Why, though, the link with breast and prostate cancer? On top of the naturally occurring hormones and growth factors in meat, most non-organic meat, particularly in the US, whether from chicken, beef, pork or lamb, also receives hormone treatment of one kind or another. Cows, for example, are given hormone pellets to increase their growth or milk yield. This practice has been officially banned in the EU since 2006, but some unscrupulous farmers still give growth-enhancing hormones to increase profit. Of course, it isn’t easy to find out what long-term effects these artificially introduced hormones are having, and have had, on us prior to them being banning.

Another large study involving 63,550 people in Britain, known as the EPIC study (European Prospective Investigation into Cancer and Nutrition), also concluded that the incidence of all cancers combined was substantially lower among vegetarians than among meat eaters. The weight of evidence is in favour of decreasing meat intake, and especially processed meat intake, to reduce cancer and heart disease risk. Those wishing to maintain optimal health should follow these guidelines:

• Preferably avoid or, at least, limit your intake of red meat to a maximum of 300g (11oz) a week, which equates to two small servings of 150g (5.oz) twice a week (roughly the amount that would fit into the palm of your hand).
• Choose lean meat, especially game, in preference to red meat or meat from domesticated animals.
• Avoid, or rarely eat, burned meat, whether grilled, fried or barbecued.
• Avoid processed meats including most burgers, sausages and pies, unless you are sure they are made from lean meat. Even then, stick to one serving a week.
• Choose organic meat or free-range chicken when you can. If you’d like to find out more about what to eat to stay healthy read Say No to Cancer and Say No to Heart Disease by Patrick Holford.