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.
