Evolving Dietary Guidelines Bring More Confusion Than Clarity
There is a fear of food in the United States–not in the obese, but in those concerned with their own health. This fear is often stoked by the media with national news headlines such as "Excess Salt Blamed for 2.3 Million Deaths From CVD Worldwide" and “Sugary Drinks May Explain 180,000 Deaths Worldwide Each Year.” Even worse news for the health conscious is that atherosclerosis, the disease responsible for the vast majority of heart attacks and strokes, was recently identified in mummies from four different ancient cultures.
Presumably, those ancient populations had lifestyles and diets more closely resembling that which Mother Nature intended for all of us. Which dietary regimen will allow us to delay the onset of cardiovascular disease for as long as possible?
The Medical Credibility Gap
While our dietary impulses may be rooted in evolutionary biology, I believe our fear of food is rooted in the suspicion that the medical establishment does not really know what causes cardiovascular disease. The public is probably aware of a changing laundry list of suspected causes and risk factors for cardiovascular disease, including red meat consumption, cholesterol, LDL, oxidized LDL, lipoprotein(a), homocysteine, Chlamydia pneumonia, tooth decay, inflammation NOS, C-reactive protein, and saturated fats. The public is certainly aware that people taking medicine to lower their cholesterol are still dying of heart attacks.
Perhaps what is most damaging to the authority of the medical establishment is that there is no consensus about the role of dietary salt in cardiovascular disease. For a thoughtful review of this fascinating controversy, I suggest reading “The (Political) Science of Salt” (link to full-text) published in the journal Science by award-winning medical writer Gary Taubes.
“While the government has been denouncing salt as a health hazard for decades, no amount of scientific effort has been able to dispense with the suspicions that it is not,” notes Taubes, a Harvard and Stanford trained physicist and engineer turned journalist.
As early as 1998, Taubes wrote, “Over the past 5 years, two conspicuous trends have characterized the salt dispute: on the one hand, the data are becoming increasingly consistent—suggesting at most a small benefit from salt reduction—while on the other, the interpretations of the data, and the field itself, have remained polarized.”
The latest research presented at the 2013 Epidemiology, and Prevention/Nutrition, Physical Activity and Metabolism conference (EPI-NPAM) shows that in the intervening 15 years very little, if anything, has changed. I submit that to the extent that the public is aware of the dietary salt controversy, shocking headlines like "Excess Salt Blamed for 2.3 Million Deaths From CVD Worldwide" are not perceived as a reasoned conclusion following a thoughtful analysis of the data, but only as one side in the debate trying hard to shout louder than the other.
This controversy has not cast science in a positive light. Rather, according to former director of the Center for Food Safety and Applied Nutrition at the Food and Drug Administration, Sanford Miller, the controversy over dietary salt is the “number one perfect example of why science is a destabilizing force in public policy.”
The Mediterranean Diet
The good news is that there is now evidence derived from the largest prospective randomized dietary trial to date to guide us in our dietary decisions. The PREDIMED study showed that adherence to the Mediterranean diet was associated with a significant reduction in major cardiovascular events. The Mediterranean diet encourages consumption of olive oil, nuts, white meat, and wine, and discourages consumption of red meat. It does not stress a decrease in fat or caloric intake.
After the disappointing failure in 2012 of a large scale study to improve cardiovascular risk prediction (the Emerging Risk Factors Collaboration trial (see also here, here, and here) and the increased mortality associated with inhibitors of cholesterol ester transfer protein, publication of the PREDIMED study provided a rare occasion for the medical community to celebrate. With an enthusiasm rarely seen in the public statements of a scientific opinion leader, cardiologist Steve Nissen gushed that PREDIMED is “a spectacular study that was extremely difficult to perform.” Not surprisingly, the study did have its critics. The bottom line is that until the pathogenesis of atherosclerosis is elucidated to the satisfaction of the mainstream, there will always be uncertainty about the efficacy of dietary interventions.
Civilization: A Victim of Its Own Success
The food industry can deliver desirable calories cheaper and quicker than they can be produced in the home. This is a major contributor to our culture of overabundance, and the price is obesity and cardiovascular disease.
Cardiovascular disease has recently become the number one killer on the planet, not just in Western and industrialized societies. The spillover costs of obesity effect not only the sick but everyone, collectively, by increasing health insurance premiums and demands on Medicare. Unless we, as medical scientists and clinical researchers, are able to establish a new paradigm for combating these trends, our future as an economy and society will become increasingly bleak.
For Further Reading: