Terri Coles of Reuters (Toronto) recently wrote an interesting article on the new Dietary Guidelines. Coles is one of the few writers who wisely made reference to the Yeshiva University study , written by Marantz, Bird and Alderman, from the Albert Einstein College of Medicine and published in January, 2008 in the American Journal of Preventive Medicine. The authors wrote that the members of the Dietary Guidelines Advisory Committee should use explicit standards of evidence in making their nutritional recommendations. If not, their recommendations could end up producing unintended consequences that may have a negative impact on public health.
Most importantly, the authors proposed that there should be alternative and more rigorous standard for evidentiary support, and went as far as to state that when adequate evidence is not available, the best option may be to issue no guidelines . Now, how courageous is that?
Imagine - saying that you should not make any recommendations until you have reliable data - extraordinary!
The New York Times, like the Washington Post, loves to "blow the whistle" on bad actors, be they corrupt politicians, greedy businessmen or hypocritical "public interest" groups. Yesterday's Science column by John Tierney on "'Misleading' Research From Industry ?" revisits a subject of repeated comment in our blogs. We've pointed out that every funding agency has an agenda when it ponies up to support health-related research. The solution: examine the methodology and the integrity of the analysis. Too often, industry-funded studies are dismissed for bias while government-funded studies are given a free pass (despite numerous examples of why they shouldn't).
Tierney briefly reviews the disparagement of industry-funded studies, lamented by the British Medical Journal as creating a "hierarchy of purity among authors," and reports:
Now some researchers have looked to see what kind of hierarchy actually exists. After analyzing weight-loss research conducted over four decades, they've found that the quality of data reporting in industry-sponsored research does seem to be different from that in other research: It's better.
The study, published in the International Journal of Obesity , concluded: "while continued efforts to improve reporting quality are warranted, such efforts should be directed at nonindustry-funded research at least as much as at industry-funded research."
Ironically, the article appeared concurrent to the first meeting of the new 2010 Dietary Guidelines Advisory Committee whose salt subcommittee chair has enjoyed millions of research dollars leading to reports that endorsed the official government policy of universal sodium reduction while specifically opposing release of the data in those studies for independent expert analysis. So, if the Gray Lady wants another whistle-blowing target there are surely many choices.
Before the age of science, the influence of the classical Greek philosophers was so overwhelming that their simple opinions were taken as divine edicts. Anaximander (610-647 BCE) spent a good part of his life teaching students that animals were miraculously formed out of pure moisture and Aristotle (384-322 BCE) proposed that animals spontaneously arose out of soil, plants or even other species of animals. These opinions resulted in the theory of the 'spontaneous generation' of life, which held sway until the Middle Ages and beyond. Even Van Helmont (1578-1644), the famous Belgian physician and chemist, recorded detailed recipes for the preparation of spontaneously generated mice. For 2,000 years, polemics were the only means of explaining nature, for never once in the history of the debate had anyone ever thought of actually carrying out experiments to prove or disprove the validity of their theories. Francis Bacon (1561-1626) was among the first to seriously question these dogmatic theories and insisted that only careful experimentation and precise observation would lead to the truth. He became the period's most eloquent proponent of methodical experimentation and has often been referred to as the 'Father of the Scientific Method'.
In applying the scientific method to the practice of medicine, the notion of "evidence-based" medicine developed. Although it is not a new concept, it has had a renaissance in recent years, and now everyone refers to their brand of practice as evidence-based medicine. The one institution that rigorously adheres to the strictest principles of evidence-based medicine is the Cochrane Collaboration . Unfortunately, within other organizations, the term "evidence-based" is often used rather loosely and routinely ignores the rigorous discipline upon which the practice is based. What is worse, there is a lack of understanding of what quality evidence actually is. The following is the accepted understanding of the hierarchy of evidence to be used in making evidence-based evaluations:At the very bottom of the quality of evidence pyramid are ideas and opinions. They are exactly the sort of pronouncements that Bacon railed against. Even expert opinion cannot be compared to scientifically generated evidence. Yet, the Dietary Guidelines and the Dietary Reference Intakes (DRIs) upon which the Guidelines are established are predominantly based on opinion - the lowest level of evidence. In fact, when the initial call for comments to the Dietary Guidelines Advisory Committee was announced, our input focused squarely on that issue. Quoting from "The Development of DRIs 1994-2004: Lessons Learned and New Challenges ," our comments (comment ID 000010) highlighted what a number of scientists originally involved with the development of the DRIs were now saying - that we have to get away from expert opinions and start basing our judgments and policies on much more rigorous science.
Unfortunately, that is not what we witnessed at the first meeting of the Dietary Guidelines Advisory Committee (DGAC) meeting held October 30-31, 2008.
As was the case with the 2005 Dietary Guidelines, the chairperson of the sub-committee for Fluid and Electrolytes for the 2010 Guidelines is Larry Appel. As it happens, Prof. Appel is listed as a member of WASH , an advocacy group whose singular aim is: "to achieve a reduction in dietary salt intake around the world." In their justification for salt reduction, WASH focuses almost exclusively on hypertension to the virtual exclusion of all other risk factors and biomarkers that are responsible for overall health outcomes. They systematically ignore all data (including the Cochrane review and its latest reissue - ) as well as the most recent evidence that demonstrates the net negative health outcomes from reduced salt diets . How a member of such an advocacy group could be selected to lead what is supposed to be an objective advisory group is quite astonishing.
At the opening meeting, Appel made his presentation to the Dietary Guidelines Advisory Committee selectively picking all evidence that supported his salt reduction agenda and ignoring all else that didn't. He mentioned a number of NHANES studies, but ignored the most recent one as well as all others that did not agree with his opinion.
When another DGAC member brought up the issue of the possible negative consequences of reduced iodized salt consumption, Prof. Appel repeated a statement he made at a recent FDA hearing. "There is no problem with iodine in this country. We don't have goiter anymore." This was a typical Greek philosopher's statement. As it happens, our iodine values have been dropping steadily during the past 30 years, and although they are not yet at a level that would be considered a public health emergency, they are tending that way . As a result of Appel's pronouncement, there was no further discussion of the iodine issue.
All in all, the first meeting of the DGAC was a great disappointment. It appears that we are once more headed towards a series of recommendations that will result from a process based far more upon opinion than on scientifically-derived evidence. It was like retreating to the notion of spontaneous generation. This is just not on, and we will continue to do whatever we can to ensure that this process get back on track and be the product of objective science, not subjective personal opinion.
As the Mark Twain observed: "Figures don't lie, but liars figure." You may have seen the headline recently heralding research that concluded that a third of all serious heart attacks can be attributed to the "fried and salty foods" in the "Western diet." Not so fast says Sandy Szwarc in Junk Food Science .
The analysis is classic "dredge data," Szwarc points out. The researchers excluded more than half the sample without explaining how the excluded subjects compared to those retained in the reported results. The data themselves were derived from a highly inaccurate post-heart attack dietary recall survey. And that typified a series of built-in biases that included "information bias," "selection bias," "observation bias," "recall bias and reverse causation." The analysis, too, confined to risk factors, was faulty with many key factors not controlled. She commends, as we do, a further read of the work of John P. Ioannidis, M.D., with the Institute for Clinical Research and Health Policy Studies at Tufts-New England Medical Center on "Why most published research findings are false ."
The way forward, she avers and we wholeheartedly agree, is with an evidence-based approach as pioneered by the Cochrane Collaboration. She explains how the process worked in a Cochrane Review of the role of anti-oxidants in cardiovascular disease . She doesn't mention it, but the Cochrane Review on salt and cardiovascular disease concluded there is no scientific basis for a population reduction of dietary sodium. First issued in 2003, that finding was reviewed and affirmed earlier this year.
This blog post should be required reading for every medical journal editor. Go figure.
Thirteen prominent scientists will constitute the 2010 Dietary Guidelines Advisory Committee (DGAC), just named today. All are content area experts. Their views on developing evidence-based recommendations instead of past DGACs' expert opinion summaries will be determined beginning at the first DGAC meeting next Thursday and Friday. Stay tuned.
Most discouragingly, the sole appointee with a "salt" background is Dr. Larry Appel, appointed despite an obvious conflict of interest not only as a partisan in the anti-salt lobbying fraternity, but the leader of the 2005 DGAC effort which included, for the first time ever, a numeric goal for sodium intake -- a level that further research has already found problematic.
From the USDA release, members of the 2010 DGAC consists of:
Linda V. Van Horn, PhD, RD, LD, (Chair) Professor and Interim Chair, Department of Preventative Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL. Dr. Van Horn has expertise extending across many areas of nutrition research and public health as a nutrition epidemiologist who has conducted population level research in the prevention and treatment of cardiovascular disease, obesity, and breast cancer. She is currently the principal investigator in the Women's Health Initiative Extension Study and the Dietary Intervention Study in Children.
Naomi K. Fukagawa, MD, PhD, (Vice Chair) Professor of Medicine and Associate Program Director of the Clinical Research Center, University of Vermont and Fletcher Allen Health Care, Burlington, VT. Dr. Fukagawa is a board-certified pediatrician and an expert in nutritional biochemistry and metabolism, including protein and energy metabolism; oxidants and antioxidants; and the role of diet in aging and chronic diseases, such as diabetes mellitus. She has chaired the National Institutes of Health Clinical Research Centers' Committee and is currently a member of the National Institutes of Health Integrative Physiology of Diabetes and Obesity Study Section.
Cheryl Achterberg, PhD, Dean and Professor, College of Human Sciences, Ohio State University, Columbus, OH. Dr. Achterberg's research has evaluated the impact of behavior on the dietary patterns of populations, including low-income and elderly Americans. She has served on panels for numerous groups, including the World Health Organization, the Institute of Medicine, and the United Nations as an expert in nutrition education and community interventions.
Lawrence J. Appel, MD, MPH, Professor of Medicine, Epidemiology, and International Health (Human Nutrition), Division of General Internal Medicine, and Director, ProHealth Clinical Research Unit, Johns Hopkins Medical Institutions, Baltimore, MD. Dr. Appel is a physician whose research pertains to the prevention of hypertension, cardiovascular disease, and kidney disease, typically through lifestyle modification, such as dietary intake of sodium and potassium. Dr. Appel served on the 2005 Dietary Guidelines Advisory Committee as a member of the science review subcommittee and Chair of the electrolytes subcommittee. He has also served on several committees for the Institute of Medicine, including the Dietary Reference Intake Panel for electrolytes and water, which he chaired.
Roger A. Clemens, DrPH, Associate Director, Regulatory Science, and Adjunct Professor, Pharmacology and Pharmaceutical Science, The University of Southern California, Los Angeles, CA. Dr. Clemens has extensive experience in functional foods and technology with a special emphasis on probiotics and prebiotics. He has expertise in toxicology and food safety, as well as knowledge of food processing and the food industry. He is a spokesperson for the American Society for Nutrition and the Institute of Food Technologists.
Miriam E. Nelson, PhD, Director, John Hancock Center for Physical Activity and Nutrition, Tufts University, Boston, MA. Dr. Nelson is a leading authority on physical activity and energy balance, with extensive research experience integrating the science of energy balance into behavior change programs. She recently served as Vice Chair of the first Physical Activity Guidelines for Americans Advisory Committee chartered by the Department of Health and Human Services.
Sharon M. Nickols-Richardson, PhD, RD, Associate Professor, Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA. Dr. Nickols-Richardson's expertise focuses on dietary and physical activity determinants of muscle strength and bone density, as well as dietary interventions for obesity and nutrition over the lifecycle from child nutrition to older adults. She served the Institute of Medicine as a consultant on the Dietary Reference Intakes book "The Essential Guide to Nutrient Requirements."
Thomas A. Pearson, MD, PhD, MPH, Senior Associate Dean, Clinical Research and Albert D. Kaiser Professor, Department of Community and Preventive Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY. Dr. Pearson is an epidemiologist specializing in lipid metabolism and the prevention of cardiovascular disease. He contributed significantly to the American Heart Association's guidelines for prevention of heart disease and stroke, and is as a founding member of the World Heart Forum for Cardiovascular Disease Prevention.
Rafael Pérez-Escamilla, PhD, Professor, Nutritional Sciences and Public Health, University of Connecticut, and Director, Connecticut Center of Excellence for Eliminating Health Disparities among Latinos, Storrs, CT. Dr. Perez-Escamilla is an internationally recognized scholar in the area of community nutrition for his work in food safety, obesity, diabetes, and food security, with a specialty in Latinos and low-income American populations. He is currently serving the Institute of Medicine in re-examining the pregnancy weight gain guidelines.
Xavier Pi-Sunyer, MD, MPH, Professor, Applied Physiology, Columbia University Teachers College and Chief, Division of Endocrinology, Diabetes, and Nutrition, St. Luke's-Roosevelt Hospital Center, New York, NY. Dr. Pi-Sunyer has expertise in obesity, type 2 diabetes, carbohydrate and lipid metabolism, and general medicine with over 250 research papers on these topics. He chaired a National Heart Lung and Blood Institute obesity committee and has served on the Institute of Medicine Dietary Reference Intake Panel on macronutrients. He was also a member of the 2005 Dietary Guidelines Advisory Committee where he chaired the energy balance and weight maintenance subcommittee.
Eric B. Rimm, ScD, Associate Professor of Medicine, Harvard Medical School, and Associate Professor of Epidemiology and Nutrition, Harvard School of Public Health, Boston, MA. Dr. Rimm is an epidemiologist whose research evaluates the impact of lifestyle factors, particularly diet, that relate to the risk for obesity, diabetes, heart disease, and stroke. He is internationally known for his work on moderate alcohol consumption and health and has served on the Institute of Medicine Dietary Reference Intakes Panel for macronutrients.
Joanne L. Slavin, PhD, RD, Professor, Department of Food Science and Nutrition, University of Minnesota, Minneapolis, MN. Dr. Slavin is an expert in carbohydrates and dietary fiber. Her research expertise focuses on the impact of whole grain consumption in chronic diseases, such as cancer, cardiovascular disease, and diabetes, as well as the role of dietary fiber in satiety.
Christine L. Williams, MD, MPH, Vice President and Medical Director
Healthy Directions, Inc., and former Professor, Clinical Pediatrics, and Director, Children's Cardiovascular Health Center, Columbia University, New York, NY. Dr. Williams is an expert in nutrition in cancer prevention and preventive cardiology, especially hypercholesterolemia, in children. She received the prestigious Preventive Cardiology Academic Award from the National Heart Lung and Blood Institute of the National Institutes of Health for her work in preventive cardiology for children.
On several occasions, we have reported on the current research linking reduced salt consumption with increased plasma aldosterone levels and their negative health consequences . We have done this as transparently as possible because this observed phenomenon is never considered by salt-reduction advocates. They focus uniquely on blood pressure as a cardiovascular risk factor to the exclusion of all else. It is little wonder that they are at a loss to explain why more people on low salt diets are apt to die than those on regular salt diets. In fact, the BPO (Blood Pressure Only) anti-salt advocates are likely to totally ignore the LSHD (low-salt, high death-rate) linkage.
Well, the LSHD linkage is not going away. The scientific evidence is mounting as can be seen in the most recent publication of Atherosclerosis . In an article entitled, "Dietary salt restriction increases plasma lipoprotein and inflammatory marker concentrations in hypertensive patients," author Edna Nakandakare and co-authors describe the impacts of placing people on low-salt diets .
Their research demonstrated that serum triglycerides, chylomicron-cholesterol, tumor necrosis factors, renin activity, aldosterone and insulin values all increased. They concluded that reduced salt intakes induced alterations in the plasma lipoproteins and in inflammatory markers that are common features of the metabolic syndrome. Metabolic syndrome is the combination of medical disorders that increase the risk of developing cardiovascular disease and diabetes.
It should be noted that this most recent example of the negative impact of reduced salt intakes also showed a drop in blood pressure. This was expected. The difference between this study and the countless salt-reduction advocacy papers that we have seen over the years is that this research went way beyond BPO. It looked at a great many other health outcomes. That's what overall health is - a composite of discrete health effects.
When reduced salt consumption is studied and a composite of health impacts is considered, the overall balance is negative. Yes, blood pressure may drop with reduced salt consumption, but at the same time, there is a cascade of negative health impacts that result on an overall negative health impact. The LSHD phenomenon is not an artifact - more and more research is taking place that will establish its reproducibility beyond any doubt.
It remains to be seen whether the scientists chosen to develop the new set of Dietary Guidelines will adequately consider this phenomenon in their evaluations - lives may depend on it.
