Much has been made of the view that red meat, including processed and preserved meats, causes Colon Cancer, in the press and television this week. The advice from the DH, is that we should reduce our intake to take account of this. This is based on the recommendation of the Scientific Advisory Committee on Nutrition (SACN). But this report is on Iron and Health, so what's that got to do with it? Moreover this report has been in gestation since 1998, yet was only published in February of this year. So it was pretty urgent then?
When you get to the report itself you will see it's pretty long and full of data, all 374 pages of it! But hang on, this report refers back to the Committee On Medical Aspects of Food and Nutrition Policy called COMA, and is likely what you will get trying to follow this trail! However let's persevere. We then find that data used by the SACN, was that provided by COMA for the survey of the Food Standards Agency (yes, that lot again!). And the data used, was from the 2000/2001 survey. Pretty up to date then!
Now we're getting somewhere! So the report on Iron and Health from the SACN, based on data from COMA via the FSA, from the 2000 National Diet and Nutrition Survey, recommends we reduce intakes of red and processed meat. OK, but where's the evidence? All the SACN say is, there is a "possible link" between high intakes of this food group and Colerectal Cancer (CRC). This report from the BBC, links the 'scare' to the World Cancer Research Fund data from 2007 and at the same time casts doubt, both on that report and on the evidence both utilised in the compilation of the advice and more importantly that ignored! Nothing like 'cherry picking' the data that supports your preconceptions then?
Most of the information about CRC and meat actually stems from the EPIC report of 2005. This is a longitudinal study and it's fourth from the top of the list with regards to evidence, the Randomised Control Trial being the 'gold standard'. EPIC is also observational and 'observation does not prove causation' as I have said many times before. If you actually look at the data, it can be seen that there are some anomalies, not supporting the view of the authors, of CRC being positively associated with red meat intake (they talk like that in 'science'). In the hazard ratios reported, and 1.00 equals no effect, we see that Italian meat eaters are in fact protected (0.96) and we in the UK have an increase in risk of about 3% (1.03).
Remembering of course all of the data is self reported, it is spread across ten EC countries with many different cultures, types of meat with both traditional and modern methods of preservation and cooking, all intermingled with other nutrients. Thus I do find it difficult for any real credence to be given to the view, that meats causes CRC. The authors seem at a loss as well to explain the mechanism, but there is allusion to excessive iron or nitrosamines (from the preservatives) which are carcinogens. I would hazard that they have far too many confounding factors, within the diet of the cohort to draw any real conclusions. There are no details of which meat (beef primarily) was fed on grass, silage or corn and wheat. What you feed to animals is critical to the meat you produce, with considerable difference in the fatty acid constituent as well as micro nutrients. So grass fed Angus Beef, has much higher n-3 than n-6. Omega 3's are said to protective against cancer, and it is certainly better to ensure that the 3's are higher than 6's, both for human intake generally, or in the meat we eat.
Is it likely as well that the meat we have consumed for thousands of years, lamb, beef, pork and game, has suddenly become toxic in the last forty years? Except perhaps by man's intervention in the form of feeding animals unnatural diets, preserving it with various chemicals that were never used traditionally, or mincing it up with other products. There are I would suggest far too many variables, to have any certainty as to whether meat consumption is the sole positive indicator for CRC.
I am not the only one with a sceptics view of this. From the Netherlands we have a study that has a contrary view. A number of scientists were unhappy about conclusions as can be seen here. This Japanese study found no connection, but also came out strongly in favour of n-3 as protective. And they were very honest in their interpretations and about the cohort size. I found many studies that did not support the view that red meat caused CRC, but found much that supported the view that processed meat and sausage did have a slight association. So what to believe then for self protection?
Well going back to EPIC, the overall risk was only increased by 1%, which is a small risk, and is not borne out by other studies, or even commonsense. Quality meat with a good content of saturated and other fats enables humans to keep their carbohydrate intake low and their level of satiety high for a given calorific load, without getting fat. To suggest that this is going to give them cancer, when we almost never had any cancers at all when society consumed a diet almost completely of meat is perverse. It is backed by the recorded good health and lack of disease in every study of 'hunter gatherers' undertaken. I posit that any association that has any foundation would be the intake of processed meats from animals that are 'lot fed', steeped in preservatives and cooked in hydrogenated oils. These can usually be found in eatery's with Scottish or Royal elements to their name and that are on every high street in the land.
So what then is the average citizen to make of all this? Constantly harangued to eat this but not that, most of which is changed somewhere down the line and then often reinstated. The bulk of this is not 'scientific' in it's true sense, because most of the research is too poor, inconclusive, or perverse. And for many years directives from Governments and it's Agencies seems to be founded in the view, that the 'proles' are too thick to have any idea of what's best for them. The scientists have held a similar view about the politicians (can't say I blame them).
Scientists in fact, are often dogmatic in their views, even in the face of contrary evidence that bursts the bubble of their hypothesis. They will biasly select that which does not confound a theory and conceal data that does. This is not peculiar just to 'Big Pharma', but to many individuals within science especially medicine, who are prepared to dance to the tune of the master or of their own ill founded dogma, for what ever motivates them. They are intolerant and even abusive to colleagues who are sceptics, about views often held for no other reason than laziness or stupidity. So at the end, we arrive at the beginning; the motto of the Royal Society; it means "on the word of no one". And so it should be.
You are clearly so correct about there being too many confounding parameters to build weighty conclusions upon. And as you say, we should always look for the evidence. Taking someone's word, however eminent the 'someone', is not scientific. We need evidence.
ReplyDeleteChris Kresser's article http://thehealthyskeptic.org/the-myth-of-evidence-based-medicine which I read today is about the very same need for evidence-based medicine/nutrition advice.
Nice one Blackdog,
ReplyDeleteThe one truth we all have to face is this. There is no 'one size fits all' when it comes to nutrition. This I learned the hard way. When my wife was killed 10 years ago I decided to go on a low cholesterol food regime. Not a diet as such because calories were not a concern. This I share with you. It damn near killed me in three years. Strength down 50%, weight down 30% but osteopena setting in. Much of the weight loss was lean muscle tissue. Need I go on? For another six years I ate a 'balanced diet' in accordance with the one size fits all school of advice. Little was noted by way of recovery.
Then I became adventurous.
Butter, not that vegetable rubbish passing off as easy spread yellow goo. Eggs, and pants to Edwina Currie and ‘vertical transmission of pathogens from hen to egg’. Corned beef butties. A range of the Co-op (good with food in a Scottish burr) Truly Irresistible range of prepared grub augmented with the darkest green I could get my hands on. Fruit back down to what I fancied when I fancied. None of this x portions a day nonsense, just when I fancied a bit of fruit, no more.
Two years in and my physical power is returning. At 64 I can carry a 25kg bag up a double sixteen ladder without a problem. Bones are returning to the jellyfish I had become. Admittedly a hundredweight bag (8 stone) is pushing it now – it was easy at the age of 25. Even my hair (oddly) is no longer getting thinner each month.
So there we have it. No one size fits all. As for red meat causing colon cancer pfttt! The jury is out on that one and unlikely to return.
Too true Widower. The consequence of veering away from 'real food', that us 'baby boomers' were given in childhood has been increases in the those diseases that we almost never heard of. Diabetes, CHD and CVD, were rare and TB was mainly that which we feared.
ReplyDeleteYour anecdotal evidence about yourself is reflected more and more in scientific study. We need to go back, to secure the future of good health.