One headline that just keeps on popping up in the media is the one about red meat causing cancer. Every few years there is a new study or report published claiming a link and it always grabs the headlines. The study published earlier this month by a research team from the Harvard School of Public Health was no exception. Published in Archives of Internal Medicine on March 12, 2012, this latest study found that red meat consumption was associated with an increased risk of total, cardiovascular, and cancer mortality.
The paper had quite a bit of coverage both in New Zealand and overseas. For example, there was an article in the New Zealand Herald; it was reported on by the BBC; and it was discussed on the Jim Mora show on Radio New Zealand.
As part of the discussion on the Jim Mora programme, nutritionist Maria Middlestead was invited to provide some comment. She made the point that correlation is not the same as causation, so it is important to look carefully at the data. For example, people who wear dresses are more likely to develop breast cancer, but of course this doesn’t mean that wearing a dress causes breast cancer.
Fiona Carruthers, who is the Nutrition manager at Beef and Lamb New Zealand, has also commented (in the New Zealand Herald) on the issue of correlation (or association) versus causation:
“As well as the questionable assessment methods, this type of study can only show an association between red meat and health outcomes, not that one causes the other. There are a number of risk factors for cancer and heart disease; obesity remains the most prevalent. Singling out one food in a condition influenced by such a wide range of factors is misleading.”
The World Cancer Research Fund (WCRF) recommends consuming no more than 500g lean meat per week, cooked weight (this is about 700 to 750g raw weight). For New Zealanders, this means that if you want to follow the WCRF advice, you could happily have five 100g portions of meat per week as long as it is lean and is part of a healthy, balanced diet that also includes lots of vegetables and cereals.
The WCRF don’t recommend avoiding red meat altogether as it is a valuable source of nutrition. Check out their website to see what the recommended amounts of meat look like — it’s quite a lot!
My opinion is that if you are clinically obese, a smoker, drink heavily, take little or no exercise, eat a poorly balanced diet low in fruits, vegetables and wholegrain cereals, and consume a large amount of meat (particularly processed meat), then making changes to your diet and lifestyle would be highly advisable.
However, for those of us who don’t smoke, don’t drink excessively, take regular exercise and are a healthy body weight, having some lean meat on a regular basis as part of a balanced diet that includes lots of fruits, veggies and cereals will not have any adverse effects on our health. In fact, meat provides such a great package of nutrients (such as haem iron, zinc, B vitamins, and protein), that it can make a very important nutritional contribution to the diet. This is especially the case for those with high nutritional requirements; for example, young children and pregnant women have high iron needs. If it’s lean, it is also low in fat, and can make a significant contribution to our intake of the unsaturated fatty acids — including the omega-3 fatty acids that are thought to be beneficial for our health.
And the final word I will leave to the University of Otago’s Professor Jim Mann, a well-respected expert in this field. Professor Mann has been quoted as saying:
’Attempts to incriminate a single food are likely to lead to inappropriate diets, diets which will not necessarily protect against cancer. To the best of my knowledge, and to the best of anyone’s knowledge, there is no evidence that moderate intakes of red meat cause any harm in terms of cancer, or indeed I might say, anything else I’m aware of. Indeed red meat is an excellent source of a whole range of nutrients.’