Re-reading the study about red meat and its increase in mortality, I continue to go back to the gold standard of lifestyle epidemiology- smoking. People who smoke one pack of cigarettes a day have a 20-fold increase in lung cancer. 86% of all lung cancers in the United States occur with smokers, or ex-smokers. One can reverse prove this- people who quit smoking decreased their risk of heart disease as well as lung cancer for every year they had stopped. This was the gold standard that all other lifestyle researchers are trying to find. After smoking the next great one was second-hand smoke, and sadly the correlations between mortality and second-hand smoke fell apart – although that did not stop public statements.
Still others try to find that meat, or fat, or carbs, or something causes an increase in the rate of death. So what did is the real red meat of this study (sorry).
What this paper discovered was that the increased risk is that less than one person in one hundred died (less than 0.2% with heart disease and 0.32% with cancer – as opposed to the gold standard of a 20 fold difference). Let us put this into the context that the article did not, and that most media did not – that one person in one hundred over a 28 year period who died also smoke more, drank more, had less physical activity, and was obese.
The article states they did a multivariate analysis to adjust for age, race, smoking, drinking, activity, caloric intake, and obesity – and removing those factors they still have, in the highest quartile, the increased rate of death with less than a 1.2 fold difference (compared to 20 fold for smoking and lung cancer). For those of you not statistically or mathematically prone, this simply means they found a way to negate the influence of each of those factors so that the simple and singular analysis of each quartile (quartile one being the lowest meat eaters and quartile 5 being the largest consumers of meat) stands alone. They do not show us this data – we just take them at their word that this person who died, the one person in 100 in 28 years, who drank more, smoked more, was obese, did minimal physical activity, and ate more meat- died because they ate more meat.
Does this study really tell us that substituting one meat free meal a week will decrease mortality? Not really. This was a statistical trick to take the people from one quartile to another- and in that they reduced risk.
If you examine the raw data, without statistical manipulations- you find that death rates go down with increased meat consumption until the fourth and fifth quartile.
Does this article shed light on how we should eat or what we should eat? No, it does not. In fact, this article is a statistical nightmare of a piece that gained attention because of its conclusions.
Take heart, there have been prospective studies of diets to see how they work, and these have been short-term studies, but they were corrected for variables. The diets examined include low-carbohydrate diets, Mediterranean diets, the Ornish diet, and others (Gardner CD, Kiazand A, Alhassan S, et al.: Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women. JAMA 297:969–977, 2007) and Comparison of the Atkins, Ornish, Weight Watchers, and Zone Diets for Weight Loss and Heart Disease Risk Reduction: A Randomized Trial Michael L. Dansinger, Joi Augustin Gleason, John L. Griffith, Harry P. Selker, Ernst J. SchaeferJAMA. 2005;293(1):43-53.)
We have moved beyond poorly done population studies – and are into trying to determine what is the best diet for people to consume. We have more questions than answers – but the science tells us a few things:
(a) No matter which died patients are placed on, if it yields weight loss (probably meaning people are compliant on the diet) reduced the cardiac risk factors including C-reactive protein, insulin levels, and reducing the low-density lipoprotein/high-density lipoprotein ratios.
(b) We really don’t know about fats, as much as we think we do
(c) No one seems to like bread these days
(d) We all like grass fed beef, flaxseed fed chicken eggs, and anything that is free on a range (home on a range).
(e) We all like whole plants- but some of us like them more than others
(f) Exercise is universally associated with better results, and you cannot exercise your way out of obesity.
To paraphrase Gary Taubes of “Good Calories, Bad Calories”- nutritional epidemiology is closer to pseudoscience than it is to science.
For part one of this please click here.
Dr. Terry Simpson
Dr. Terry Simpson received his undergraduate and graduate degrees from the University of Chicago where he spent several years in the Kovler Viral Oncology laboratories doing genetic engineering. He found he liked people more than petri dishes, and received his MD. Dr. Simpson, then became a renowned weight loss surgeon, and a leading advocate of culinary medicine. The first surgeon to become certified in Culinary Medicine, he advocates teaching people to improve their health through their food. On the other side of the world, he has been a leading advocate of changing health care to make it more "relationship based," and his efforts awarded his team the Malcom Baldrige award for healthcare in 2011 for the NUKA system of care in Alaska. A frequent contributor to media outlets discussing health related topics and advances in medicine, he is also a proud dad, husband, author, cook, and surgeon “in that order.” For media inquiries, please visit www.terrysimpson.com.