We take a look at the World Health Organisation's latest findings on links between red meat and cancer - and what this could mean for your diet.
Picture of red meat.
Is this the end of the great Aussie BBQ?
By now, you would have seen it splashed across the news: a report published by the International Agency for Research into Cancer, part of the World Health Organisation, on the links between red and processed meat and cancer.
Our scientists, Dr Trevor Lockett and Dr David Topping, respond to the findings of the report – and what it might meant for your diet.
In light of the findings from the World Health Organisation, should we be worried about how much red meat we eat?
Australians should be confident that red meat remains an important component of a healthy balanced diet. Red meat provides an important source not only of protein but also iron, zinc and vitamin B12. The report doesn’t show any causal link between red meat consumption and cancer in general. While a small but statistically significant increased risk of developing colon cancer has been observed amongst the highest consumers of red meat, other factors may modify this risk. For example obesity, smoking and lack of exercise increase the risk of colon cancer.
What the report does provide, however, is an important reminder to take note of the amounts of red meat that we do consume, and what we eat it with. The Australian Dietary Guidelines recommend we consume no more than 455 grams of cooked of lean red meat per week – or around 650 grams of raw meat. This equates to 65 grams per day. As a rule of thumb, that’s around 100-200 grams of meat, three to four times a week, in order to maximise the benefits of red meat and minimise the risks.
The Australian Dietary Guidelines recommend we consume no more than 455 grams of cooked lean red meat per week. This equates to 65 grams per day.
The National Nutrition and Physical Activity Survey shows that Australian women and children consume slightly below the recommended 65 grams per day to meet their iron and zinc requirements. Men on average eat slightly over 65 grams per day and so could reduce their portion size.
For processed meat, the report estimates that for every 50 gram portion we consume daily, the risk of developing bowel cancer at some stage in our life increases by about 18%. For red meat the numbers are estimated to be 17% per 100 gram serving, consumed daily. That is, of course, if the cancer is in fact caused by the meat, and this isn’t yet clear.
At the level of the individual, these effects are quite small. But they can have significant impact at a whole-of-population level, where more people may be consuming higher levels of these products.
What you eat meat with is also important. Population data suggest that consumption of dietary fibre and red meat can reduce any risk of bowel cancer substantially. This is a very important point both for public health and personal wellbeing. Recent research we undertook with Flinders University has shown that a consumption of high levels of a special form of dietary fibre (resistant starch) with a high red meat diet reduced the level of DNA damage in colonic tissue, relative to that in volunteers consuming high red meat alone.
So, a balanced diet including sensible levels of red meat but also plenty of fibre from grains, legumes, vegetables and fruit, is a practical way of reducing your cancer risk – while also providing a good eating experience.
Do the Australian Dietary Guidelines need to be changed to reflect the nature of the new findings?
It seems unlikely that we would need to, but any decision should await a full and detailed independent consideration of all the data. The report published this week in the Lancet was a summary of the findings from the research. The full article describing the details of the scientific method and results is yet to be published, and the devil will be in the detail. It is worth noting, however, that the effects seen are small, and are associated with habitual high level intakes of red meat. Alternative contributors to cancer risk, other than red meat consumption, cannot be ruled out. While the report suggests a causative relationship between bowel cancer and processed meat products, again these increased risks have been associated with high-level, long-term consumption of processed meats. The risk increases are small, and the extent to which they are associated with curing or preservative agents – some of which are not used in Australian processed meat products- is unclear. Consumption of processed meats as discretionary foods would still seem appropriate.
Overall, the benefits of red meat should balance the risks. Further, while large daily intakes of processed meats may not be recommended, their occasional consumption should probably also be acceptable. The results of this study will help us reassess our current national recommendations.
Does our Total Wellbeing Diet need to be updated to reflect the nature of the new findings?
At this stage, no. We will take great interest in the full paper once it is published, and would certainly look to review our dietary recommendations in line with any changes to the Australian Dietary Guidelines should they occur.
It is important to remember that, unlike some other weight loss diets, the Total Wellbeing Diet is a nutritionally-balanced diet that incorporates good levels of dietary fibre – which has been shown to oppose many of the health risk factors associated with red meat consumption. In fact, the fibre content included in the Total Wellbeing Diet sets it apart from many other diets, thanks to the benefits of consuming a range of fibre sources.
For more information on the Total Wellbeing Diet, visit our website.
5th November 2015 at 11:47 am
‘recommended 65 grams per day to meet their iron and zinc requirements’. Seeing that many vegetables, pulses and grains contain large amounts of zinc/iron, this raises the question as to whether/why this has/hasn’t been factored into the CSIRO diet?????
9th November 2015 at 2:04 pm
Hi Andrew
We passed your question over to some of our food scientists, who responded:
“Recommendations regarding red meat have been incorporated into the most recent Dietary Guidelines for Australians which state that over a week, a maximum of around 7 serves (1 serve = 65g cooked or 100g raw weight) of lean red meat is recommended, highlighting that lean red meats are a particularly good source of iron, zinc and B12 and are easily absorbed by the body (http://www.eatforhealth.gov.au/).
It is the bioavailability of iron and zinc in red meat relative to legumes that is considered beneficial. Dietary modelling commissioned by the National Health and Medical Research Council made the above recommendations for that reason.
The CSIRO Wellbeing Diet includes lean red meat 3-4 times per week which does not exceed 700g raw weight per week. The diet also contains fish, whole grains and fruit and vegetables, the latter of which are associated with reduced risk of cancer. More recently, the diet has also focussed on choosing low glycaemic carbohydrates, because higher protein, low GI diets have been associated with greater weight loss retention.
The net effect of the CSIRO Total Wellbeing Diet, which includes balanced nutrition, weight loss and exercise, is that it has a beneficial effect on health.”
Thanks
Nick
CSIRO social media
5th November 2015 at 11:43 am
The Greek poet Hesiod said ‘observe due measure; moderation is best in all things’
2nd November 2015 at 12:20 am
No causal link, just a statistical correlation. Pretty poor science I think.
3rd November 2015 at 4:41 pm
Agree with Julian Mattay. The increase in bowel cancer correlates quite well with internet uptake and Halloween costume popularity too. Also glad CSIRO published your response. Mine was perhaps too critical of their sensationalist use of risk increase, as opposed to true risk, and hasn’t graced these hallowed pages. For a scientific body they seem awfully sensitive to criticism.
1st November 2015 at 9:42 pm
This is an exceptionally lame response. Just admit that the meat industry sponsored Total Wellbeing Diet needs revision and get on with it!
4th November 2015 at 9:02 am
Hi Grahame, some of the research behind the Total Wellbeing diet was funded by Dairy Australia; Goodman Fielder; Meat and Livestock Australia; The National Heart Foundation; The National Centre of Excellence for Functional Foods; The Pork CRC, the Egg Nutrition Council and The National Health and Medical research Council. This information can be found in the acknowledgement section of the books.
As stated in the blog post, we will certainly look to review our dietary recommendations in the Total Wellbeing Diet in line with any changes to the Australian Dietary Guidelines should they occur.
Thanks
Nick
CSIRO social media
8th November 2015 at 10:56 am
if you are waiting for a bunch of politicians to read the science and make a recommendation we are in for a long wait. You’ve known for over ten years but still accepted the money from Meat & Livestock Australia and pushed for red meat consumption.
1st November 2015 at 5:42 pm
Bit disappointed actually. It’s forgivable for sensationalist Tabloids newspapers to say something like “the risk of developing bowel cancer at some stage in our life increases by about 18%” but a scientific organisation should explain what a non-red meat eater’s risk is to begin with.
Bit disappointed actually. It’s forgivable for sensationalist Tabloids newspapers to say something like ” the risk of developing bowel cancer at some stage In our life increases by about 18 % ” but a scientific organization should explain what a non-red meat eater’s risk is to begin with.
If you’re wondering why the same sentence is repeated, it’s because the second one is 18% longer.
Comparisons have to be in context to be useful.
Forget 18%, I can increase my chances of winning lotto by 100% by buying two tickets, but it only changes from 1 in 8 million to 1 in 4 million.
Must do better 🙂