April 2008

Essays

Geoff Russell

Confounders

The CSIRO and the total wellbeing diet

The Commonwealth Scientific and Industrial Research Organisation (CSIRO) is the major publicly funded research body in Australia, employing more than 6500 people in almost 60 sites across the nation. Its name is synonymous with science. How could Australians have BBQs if the CSIRO hadn't invented Aerogard? When we use money to pay for things, we hand over CSIRO-devised polymer banknotes; the more technologically savvy use WiFi, purportedly (but disputably) covered by a CSIRO patent.

Other CSIRO achievements have been less well publicised, though they are arguably more important. CSIRO scientists invented the main technique for measuring mercury in fish. It is measured at levels reminiscent of needles in haystacks: fractions of parts per million. And the CSIRO is a critical part of the international team monitoring methane levels in the atmosphere, measured in even smaller units: parts per billion (PPB). The current level is 1774 PPB, more than double what it was 200 years ago - something to which I will return.

The CSIRO, in short, has a well-justified reputation for scientific excellence.

In late May 2005, this prestigious scientific organisation launched a diet book, The CSIRO Total Wellbeing Diet. Despite attracting criticism from nutritionists, including Rosemary Stanton, for its high protein content and its research basis, the Total Wellbeing Diet was a dazzling commercial success, for a time even outselling Harry Potter.

Not a year later, in March 2006, four scientists published a short paper in a scientific journal. Three of the four worked for the CSIRO then, and all work for the CSIRO now. The article begins simply:

Colorectal cancer is a socio-economically important disease in affluent societies and epidemiological data suggest that dietary composition is a major factor in its etiology. Earlier reports suggested that high intake of red or processed meats could be a risk factor. Three large [human] population studies have recently confirmed those earlier reports.

This is just one of a number of papers by CSIRO researchers on the link between red meat and colorectal cancer.

The four scientists, having described the state of research in the area, continue with a description of an experiment. Groups of rats were fed various diets with and without red meat, and with and without a special form of starch. There was nothing unusual about the meat: the authors described buying it at Adelaide's central market. But the starch was special. It's part of the much-touted nutraceutical industry - designer foods with heavily hyped health benefits that attract a premium price. The CSIRO has a number of patents in this area.

Why were the scientists doing this research?

Because DNA damage is an early step in the initiation of cancer, these findings suggest that increased DNA damage due to high dietary protein as cooked red meat or casein could increase colorectal cancer risk but inclusion of resistant starch in the diet could significantly reduce that risk.

Put simply, if the DNA damage in rats eating red meat with special starch is less than the damage in the rats eating red meat alone, then a resourceful marketing department can say things such as, "Years of research by CSIRO scientists have given us an improved form of starch that dramatically increases bowel health." A statement like this, linked to the respected CSIRO brand, is a recipe for mega-dollars.

But doesn't this involve the CSIRO in a serious contradiction? On the one hand, it is lending its name to a diet high in foods that damage colon DNA in ways that could go on to become colorectal cancer. On the other, its researchers are developing and patenting products to reduce that DNA damage.

Documents obtained under Freedom of Information legislation in late February 2008 show that the CSIRO board was informed of the work of its bowel-health researchers at its April 2006 meeting. It was told: "Recent findings from [CSIRO] scientists have established that diets high in red meat, processed meats and the dairy protein casein can significantly increase the risk of bowel cancer."

In late October 2006, in time for Christmas shoppers, the second edition of The CSIRO Total Wellbeing Diet was released, at a launch attended by Julie Bishop, the then federal minister for science. The second edition contains a page discussing red meat and colorectal cancer, including this statement: "Studies have shown that fresh red meat (beef and lamb) is not a significant risk factor for colorectal cancer."

Why the clear discrepancy between what the organisation's researchers were telling it privately and its advice to the public? Had any new evidence emerged to alter the opinions of its researchers? Certainly the board and CEO documents don't mention any new research containing contrary findings.

The CSIRO was clearly concerned about the research findings because it set up a team to act as a "translator" of the science of this complex area for the public. It took heart from the findings of a special CSIRO working group: "Specifically, in relation to the association between red meat and processed meat and colorectal cancer, the CSIRO working group did note that the magnitude of effect was small and that population studies had not always adjusted for potential confounders."

Suppose a group of meat eaters gets more lung cancer than a group of vegetarians. Is it because of the meat? Not necessarily. Perhaps it's simply because more of the meat eaters happen to smoke. Smoking is a confounder.

Accusing people of not adjusting for confounders has a rather disreputable pedigree in public debate about science. Big Tobacco was fond of saying that tobacco doesn't cause cancer; there's just a correlation. Similarly, climate-change sceptics say that even if the planet is heating up, we can't be sure that it is the result of human activity. As with the best of bad arguments, this relies for its power on a grain of truth: causation is tough to prove.

In September 2006, senior CSIRO executive Alastair Robertson wrote, on behalf of the board, "The largest European study did find that there was a small increase in risk associated with red and processed meat. However, this study did not adjust for the many confounding factors." Professor Robertson was referring to the European Prospective Investigation into Cancer and Nutrition (EPIC). It adjusted for the following factors:

The results were adjusted for estimated energy intake, which was divided into energy from fat and energy from non-fat sources to control partly for error in estimated intakes of foods. To control for body size and obesity, we adjusted for weight and height. Further adjustment included smoking (never, former and current smoker), alcohol intake (grams per day), dietary fibre (grams per day), and occupational physical activity (no activity, sedentary, standing, manual and heavy manual). In some models, meat and fish intakes were adjusted for each other. The results were adjusted for dietary folate and use of multivitamin supplements at baseline in 409,135 control subjects and 1176 case patients for whom information on dietary folate was available in the dataset. Separate analyses were done for men and women. Analyses of women were adjusted for use of hormonal replacement therapy.

This was a very careful study. Some of its findings were reinforced in late 2007 by the release of a report by the World Cancer Research Fund (WCRF) in combination with the American Institute for Cancer Research (AICR), which, as the CSIRO board papers note, contains

recommendations to limit the intake of [fresh] red meat and processed meats. This was largely driven by their associations with colorectal cancer ... The WCRF panel noted that the evidence on red meat and processed meat in relation to colorectal cancer was stronger than in the mid 1990s and was now deemed to be convincing.

Using Australia's current levels of red- and processed-meat consumption, one international study calculated that cutting back red meat to one serve per week could save 840 lives (the equivalent of half the nation's annual road toll) and 2200 new cases of colorectal cancer per year. This is a minimal estimate from a respected source (it appears in the International Journal of Cancer), which confines its findings to red meat alone. In a journal supplement, published last year, of studies paid for by Meat & Livestock Australia, another researcher estimated that there could be 1950 fewer cases annually. These are estimates at the lower end of the spectrum.

And we are not, of course, talking about a minor disease. Thirty per cent of colorectal cancer cases present as emergencies, and 20% of these people are dead within a month. Australia, along with New Zealand, has the highest rate of colorectal cancer in the world, which translates to about 12,500 new cases each year, with about 4300 deaths. According to the Australian Institute of Health and Welfare, "Colorectal cancer is a disease besetting affluent countries. The age-standardised incidence per 100,000 population is an average of 37 for more developed countries and ten for less developed countries for males, with Australia having a very high rate by world standards of 50."

By the time the second edition of The CSIRO Total Wellbeing Diet went to press, someone at CSIRO had obviously decided the findings of the largest European study needed to be acknowledged, rather than dismissed. This claim was included: "people who eat lots of red meat but also eat lots of fish are not at any increased risk [of colorectal cancer]." But is fish really a red-meat antidote? The late-2007 report from the WCRF and the AICR looked at all the research into the links between colorectal cancer and fish consumption. It considered 19 high-quality studies. Nine found that fish intake decreased colorectal cancer risk and eight found that fish increased colorectal cancer risk, so the report's authors rightly regarded the evidence as inconsistent and hence didn't advise people that avoiding colorectal cancer is simply a matter of consuming more fish.


Given the growing weight of findings about links between red and processed meat and cancer, there is a strong case for caution when it comes to the Total Wellbeing Diet. The key point concerns the quantity of meat consumed. There are simply no long-term scientific health studies on any population of people eating the levels of protein - let alone red and processed meat - in the Total Wellbeing Diet.

In its basic "weight-loss" form, it is a very-low-calorie diet recommending 200 grams of red meat on four nights of the week, with 200 grams of fish on two nights and 200 grams of chicken or pork on the remaining night. Every day for lunch it recommends another 100 grams of red meat, fish, turkey, pork or ham. If you don't like fish or chicken, you can leave them out and substitute more red meat. If you really like eggs, you can leave out the lunch meat and eat 14 eggs instead. So the minimum amount of red meat a CSIRO dieter eats is 800 grams per week, plus whatever is eaten at lunch. The sample diets in the second edition specify eight weeks of menus averaging 980 grams per week of red and processed meat. And if you don't like, can't obtain or can't afford fish, then you could substitute red meat for the 600 grams per week of fish in the recipes and be getting 226 grams per day of red meat.

The Total Wellbeing Diet is modelled after a diet used in CSIRO clinical research that involved 100 women for 12 weeks. Half the women were on a high-protein test diet, and half were on a conventional high-carbohydrate low-fat diet. Both diets contained the same number of calories. The high-protein diet contained 200 grams per day of red meat, plus another 100 grams per day of lunch meat, chicken or fish, with a whopping 34% of calories from protein. All up, the people on the research diet were consuming just 1333 calories (5600 kilojoules) per day.

Once your weight has dropped to your target level, assuming you can stick to the suggested formula, the Total Wellbeing Diet advises you to add 120-calorie blocks until your weight is stable. To bring a 1300-calorie-per-day weight-loss diet up to a stable-weight-control diet of, for example, 2500 calories or so would require ten additional blocks per day. If even one of these is a red-meat block, you get an additional 700 grams per week of red meat. Eating 400 grams per day of lean red meat, plus three or four eggs every day, is consistent with the dietary advice of the Total Wellbeing Diet and, according to the second edition of the book, will pose no health risks.

The use of the word ‘whopping' above may seem a rhetorical flourish, but this proportion of protein really is unusual. The European EPIC study contains a chart that shows increased risk according to red- and processed-meat intake. But no one involved in that study anticipated the levels of red and processed meat that people on the Total Wellbeing Diet can eat, so the chart runs out at about the point where Total Wellbeing Diet intake levels start. With the levels of red- and processed-meat consumption allowed by the CSIRO diet, any estimate is sheer guesswork, for such levels are literally off the charts.

Here's what is known about protein and health. When the percentage of your calories from protein drops too low, you die. When it is too high, you die. The latter condition is in scientific literature called rabbit starvation or protein poisoning. It can be observed in hunting groups that live on meat. When the animals are starving and lean, people can eat all the lean meat they like, but they still die without additional sources of fat. They can't work physically after just a couple of weeks, and a few weeks later they die.

Between the two extremes is a healthy range; Australia's National Health and Medical Research Council (NHMRC) considers this to be between 7% and 25%. Above 25% is a grey range. Nobody knows what happens in the long term to people eating these levels of protein, as there is simply no long-term scientific data. The meat-centred diet trialled by CSIRO researchers and then published as The CSIRO Total Wellbeing Diet involves a protein level of greater than 30%. Why doesn't the Total Wellbeing Diet - which is put forward as not just a diet, but a lifelong eating plan - carry a warning that its protein levels are above those suggested as an upper limit by the NHMRC?

 


There are other, broader concerns stemming from the Total Wellbeing Diet. One is that a diet high in red meat has important environmental consequences. Globally and locally, the biggest driver of deforestation is conversion to pasture, with world deforestation accounting for some 20% of all CO2 emissions. The grazing animals that populate this pasture are prodigious producers of methane as they convert grass to body mass. While global warming due to methane is about a third of that due to CO2, the emissions of some countries - notably Australia, Brazil and India - have an unusual structure due to their high livestock populations.

Because CO2 remains airborne for more than a century, it is essential to reduce CO2 emissions quickly. For every 4 tonnes added, 1 tonne will still be heating the atmosphere half a millennium later. By contrast, methane is a very powerful greenhouse gas with a relatively short lifespan. And while CO2-emission reductions are complex and costly because they cross many economic sectors, the mitigation of methane emissions is generally far simpler. Australia had 170 million sheep and lambs in 1990, and it has about 100 million now. This reduction was driven by market forces and was unplanned, but it does show how rapidly reductions can occur.

We have more cattle than people in Australia, and five sheep for every person. We don't run air conditioners 24 hours per day, seven days per week, nor do we drive our vehicles non-stop. But cattle and sheep, through their fermenting gut bacteria, produce methane continuously. Annually, Australian livestock produce about 3 million tonnes of methane. For the decade or so that a tonne of methane is in the atmosphere, it has 72 times the warming impact of a tonne of CO2. Thus, 3 million tonnes has a warming effect equal to 216 million tonnes of CO2. (Australia's passenger vehicles produce about 43 million tonnes of CO2 annually; all our coal-fired power stations, 180 million tonnes.) Methane reductions therefore offer a unique opportunity to rapidly and effectively reduce our global-warming footprint. They offer a way to achieve huge gains quickly while work is done on the more difficult task of cutting back CO2 emissions.

Most public information about how people can reduce their carbon footprint is based on the assumption that power stations and automobiles are the only emitters worthy of attention. This has given methane a low profile, even though it is the most important greenhouse gas after CO2. Globally, livestock are the biggest anthropogenic source of methane, with the production of red meat resulting in about double the methane of rice production for a mere 10% of the food calories. In this sense the carbon intensity of beef is about 20 times greater than that of rice.

But does the CSIRO know about methane? Remember the 1774 parts per billion: it knows. In January 2008, the chairman of the Intergovernmental Panel on Climate Change (IPCC), Rajendra Pachauri, called on people everywhere to reduce meat consumption as a means of reducing greenhouse-gas emissions: "Please eat less meat - meat is a very carbon-intensive commodity - this is something that the IPCC was afraid to say earlier, but now we have said it." And NASA's chief climate scientist, James Hansen, has been advocating a 40% reduction in anthropogenic methane for at least a decade. He recently echoed the IPCC's call: "in our personal lifestyles," he said, "the most effective action [to curb global warming] is to begin to alter our diet more toward vegetarian."

 


The last decade has been difficult for the CSIRO. Spending on research declined. Respected climate scientists such as Graeme Pearman and Barry Pittock were muzzled on global warming. From 2002 to mid 2006, the CSIRO's executive director of communications was Donna Staunton, a former head of the Tobacco Institute of Australia and a long-time tobacco-industry lawyer. There have been questions about the CSIRO's sources of funding and the independence of its research. As Rosemary Stanton and Gyorgy Scrinis wrote in the Sydney Morning Herald:

The CSIRO's [dietary] research was partly funded by the Meat and Livestock Industry and Dairy Australia. So it is no surprise the sponsors' products figure so highly in the recommended meals and weekly meal plans: beef, lamb and dairy products.

The CSIRO's endorsement of a high-meat diet is perhaps an indication of the extent to which our scientists have taken on the role of consultants to industry in their bid to raise funds, and their willingness to deliver research findings that industry finds agreeable.

How responsible is it ... to be recommending such a high-meat diet in the context of concerns over the ecological sustainability and health problems associated with high meat consumption?

The CSIRO has a strong record of fostering Australian inventiveness and contributing to scientific discovery. Like any good public servant, its advice needs to be frank and fearless - and absolutely independent of commercial concerns. The Total Wellbeing Diet surely marks a low point in a proud history.

Cover: April 2008
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