Available evidence suggests that the association between red meat consumption and risk of cancer is not causal and may be explained by unhealthy diet and lifestyle risk factors, which includes excessive consumption of red meat. 

It is important to consider diet and lifestyle patterns because these are known risk factors for cancer and other chronic diseases such as cardiovascular disease and type 2 diabetes. These include overweight/obesity, smoking, alcohol, physical inactivity and low intake of fruit, vegetables and dietary fibre.

Red meat and processed meat include a wide range of different products which are produced and consumed in a variety of ways across countries around the world. These differences combined with differences in diet and lifestyle risk factors may explain inconsistent findings where increased cancer risk has been reported in some populations, but not in others. 

It is unclear whether certain aspects of red meat such as high temperature cooking methods and nitrosamine formation caused by excess haem iron or nitrites (added to cured or fermented meat only) has an independent effect, separate to that of an unhealthy diet and lifestyle.

Since fresh red meat such as beef and lamb are important sources of iron and zinc in the Australian diet, 455g/week of cooked red meat is recommended as part of a healthy, balanced diet in the Australian Dietary Guidelines.

There is no evidence that eating lean red meat as part of a healthy, balanced diet and lifestyle in amounts recommended in the Australian Dietary Guidelines is associated with increased risk of cancer.  Where increased risk associated with red meat consumption has been reported, intakes exceed 100g/day cooked meat and tend to be associated with unhealthy diets and lifestyles. 

Hence, 455g/week cooked meat represents the ideal amount of red meat required for good health,  served in portion sizes of 100 to 200g (raw weight), 3 to 4 times a week. In addition, it is also important to ensure the rest of the diet provides a variety of sources of dietary fibre, including wholegrain cereals and bread, legumes, vegetables and fruit.

Many Australian women and children need to eat more red meat to meet the recommended 455g/week whereas some men may need to reduce their portion size.

References:

  1. NHMRC (2013) Australian Dietary Guidelines. Canberra: National Health and Medical Research Council.
  2. IARC Monograph Series. Carcinogenicity of consumption of red meat and processed meat. Lancet Oncology Oct 26, 2015, http://dex.doi.org/10.1016/S1470-2045(15)00444-1
  3. Alexander DD, Weed DL Miller PE et al. Red meat and colorectal cancer: a quantitative update on the state of the epidemiological science. J of Am College of Nutr, DOI:10.1080/07315724.2014.992553
  4. Wang X et al. Red and processed meat consumption and mortality: dose-response meta-analysis of prospective cohort studies. Public Health Nutrition doi:10.1017/S1368980015002062
  5. World Cancer Research Fund/American institute for Cancer Research. Continuous Update Project Report: food, nutrition, physical activity and the prevention of colorectal cancer. 2011
  6. Aleksandrova K et al. combined impact of healthy lifestyle factors on colorectal cancer: a large European cohort study. BMC Medicine 2014, 12:168 http://www.biomedcentral.com/1741-7015/12/168
  7. Muir JG, Yeow EGW, Pizzey C et al. Combining wheat bran with resistant starch has more beneficial effects on fecal indexes than does wheat bran alone. Am J Clin Nutr 2004;79:1020-8
  8. Le Leu RK et al. Butyrylated starch intake can prevent red meat-induced O6-methyl-2-deoxyguanosine adducts in human rectal tissue: a randomised clinical trial. Br J Nutr. 2015 Jul;114(2):220-30. doi: 10.1017/S0007114515001750. Epub 2015 Jun 17