The study, published in the Archives of Internal Medicine is an observational study, which means it is not presenting any evidence, merely drawing conclusions from data provided by food frequency questionnaire's filled in by the cohort every four years! I can't even remember what I had for dinner last Tuesday, except to know it would have had meat in it; probably lots of it. These epidemiological type studies are really the starting point of a hypothesis to test it's credibility. They are not the end point, merely the beginning of a journey that should encompass all of the checks and balances that science should pursue to ensure that any statement made about anything should at least be founded in proven fact. So, is it likely that the cohort from whom the data was drawn, reported the facts of their diet without telling a few little lies? I really think not, but that's a side issue really.
Let us then look a little deeper. Firstly we see that all meat, processed or otherwise so long as it's red, is alarmingly 'lumped' together, although they do within the study provide some separation of the two and indeed indicate that 'processed' meats are more harmful than other types. But looking further we find that the actual questionnaire lists hamburger meat as 'unprocessed'. You can read about the reliability of Food Frequency Questionnaires here. This highlights the tendency for the cohort to over report socially acceptable foods rather than those they have been 'brainwashed' to reject, but nonetheless still consume. It may also not escaped your attention, that it is the same Institution that also produced this study. Ironic? I could not comment.
So 'hamburger' meat passes for red meat in the US. And to some extent, if you want to give credence to any of this rubbish then remember that the cohort is entirely comprised of US citizens. There is meat, and then there is American meat most of which is 'lot fed' in corrals most of it's life and fed on concentrates of soy protein, cattle corn and antibiotics. It's no longer meat as we know it! Europeans although consuming meat of this type in small amounts, generally eat grass fed beef and lamb, the latter of which is a large part of their 'red meat' diet. So if this study proves anything (and I don't think it does) it proves that eating US meat and all the other elements of the diet, of those who filled in the Questionnaire, could possibly, maybe, cause Cancer. Of course there are numerous confounding factors that go unreported such as, what other elements of the diet examined might be contributory to the conclusions about Cancer? All of the cohort may have also drunk vast amounts of alcohol or worse, coke! They may have all been drug addicts for all we know, because it is unreported.
Looking then at the science, about the higher reported incidence of Cancer in those who ate lots of processed meats. There is a mechanism that could be responsible, and again it's something that predominates more in the US than Europe or the UK, and that's nitrites. They are an additive used in the preservation of hams, sausages, bacon and continental sausage. Sodium Nitrite (E250) is used to add colour but more to prevent the growth of the bacteria Clostridium Botulinum, the cause of botulism.
When man started to preserve meat, natural sea or rock salt and air drying were the main agents, but as we became frightened of salt and to speed up processing we began using chemicals. Preserving salts today have the addition of 0.6% sodium nitrite or the potassium version to guard against botulism because we now turn around the processing of meats so quickly that it is much more probable, well not really (anymore) but it does make the product nice and pink. Many long matured air dried 'artisan' sausages do not need it and it's a good idea to avoid it if possible. It is not much of a poison the Lethal Dose 50% (LD50) is 71mg per kilo for humans but nitrites form nitrosamines, which are carcinogens, if they are heated in cooking at high temperature. The highly acidic environment of the human stomach can also bring about the same condition. So it is usual, and a legal requirement in the US, to add ascorbic acid (Vitamin C) at 550 ppm to preserved meat or any meat treated with nitrites. The acid inhibits the formation of nitrosamines and in fact the incidence of stomach cancer fell significantly in the US after its addition to preservation methods.
It is a good idea not to roast ham or fry bacon so that it is charred or too crisp, or to limit intake. If one does eat bacon crisp, which is the way most like it, then take a Vitamin C supplement, it helps to prevent Cancer anyway and is rarely harmful. Alternatively eat high quality processed meats that do not have nitrites, although you may have to go to some lengths to find them. Nitrites can also be found in many green vegetables and root vegetables especially, so you do not want to overload on these either. Lettuce, Spinach and Radishes contain the most and a significant proportion of this can be attributed to the use of nitrate fertilisers. The more mature the plant the lower the level of nitrite. Organic vegetables are usually lower in nitrites than those grown by the multinational growing cartels.
A rare result of over consumption can bring about methaemoglobinaemia, which robs the haemoglobin of its oxygen absorption capabilities and causes hypoxia (oxygen starvation). But one would have to consume vast amounts of nitrites for this to come about and most cases are due to other causes. Again an intake of Vitamin C is both the treatment for this rare disorder and is protective against nitrosamine being formed from nitrite ingestion. Most animals produce their own Vitamin C to combat this but a few, including man lost this ability at some time in the evolutionary chain. And to get enough of this vitamin, drinking orange juice will not cut it I'm afraid. Orange juice is flavoured with err... orange flavouring, because natural orange flavour only lasts hours. So, the processors have to add it back to the packs and bottles it comes in, otherwise it's orange water. Man cannot get enough from diet of this vitamin in today's nutritional environment unless we supplement or eat targeted foods high in its content with watercress being one of the best. However, most green leafy vegetables including cauliflower provide substantial amounts, but yes are also high in.....nitrites! Oh, just take a pill!
So eating preserved meats does have a mechanism that could be causative of some cancers, because it does actually exist, but frankly you would have to eat really large amounts, on a regular basis. And, the bun surrounding the 'unprocessed' burger meat (sic) is likely to be more harmful. And what country is renowned for it's consumption of burgers and barbecued meats? Might that be the country of origin of the cohort of this study, the USA? Always remember, long suffering reader, that observation (and correlation) does not prove causation.
Loss of innocence (part four) continues shortly.