Thomas Frieden MD, Director of the Centers for Disease Control and Prevention, responded to the latest volley in the ongoing salt battle with a contrary editorial to the Washington Post last week. He was responding to an amazingly revealing article by Marta Zaraska entitled Pass the salt, please. It’s good for you. Frieden characterizes the report as “dangerously misleading.” However, it is his adamantine assertions based on conventional wisdom, rather than good science that are dangerously misleading.
Frieden states that “While a few studies suggest that too little salt increases health risks, they have major design flaws. The best research clearly shows that reducing sodium benefits everyone.”
This statement is based upon the widely accepted salt hypothesis. The argument is that salt, specifically sodium, makes us retain fluid. Through this mechanism it increases our blood pressure. An increased blood pressure is defined as hypertension. Hypertension is a risk factor for cardiovascular disease. Therefore more salt or sodium is bad and less is better. In fact the US dietary guidelines specifically state that since there is no known detriment to reducing sodium intake it behooves us all to get as low as we can go.
The sine qua non was based on the animal modeling of genetically inbred salt sensitive rats in the 1960s and early 1970s. Despite the dearth of overwhelming and irrefutable evidence that this in any way applied to the human condition; sodium intake guidelines were adopted in the 1977 dietary goals for the United States by the United States Senate.
Since that time the vast majority of studies have attempted to prove this point; which of course is why there are many, many more studies investigating the relationship, effects and interventions between sodium consumption, hypertension and disability and disease.
The efforts to connect these dots has remained as elusive as the Grail. Specifically with respect to the benefit of lowering of dietary sodium, the answer is in the absence of findings. In 2011 the Cochrane reports (a gold standard of unbiased meta-analysis) found no strong evidence” that reducing salt intake reduced mortality. Perhaps even more telling, was the additional conclusion that “after more than 150 RCTs [randomized controlled trials] and 13 population studies without an obvious signal in favor of sodium reduction, another position could be to accept that such a signal may not exist.”
The recent examination of the potential detrimental effects of reducing sodium intake has been carried out by well-respected researchers and published in peer-reviewed journals. The University studies have been performed in Europe and North America and involved tens of thousands of individuals. The findings across the board have been amazingly consistent. This is hardly the result of a few rogue, crackpot scientists performing flawed research in their basement.
More research will no doubt be likely forthcoming. It is highly probable that we will continue to learn the importance of the sodium to potassium ratio and how this variable plays into all the complexities associated with sodium consumption. At the present, multi-million-dollar public health initiatives like the Million Hearts program are vigorously promulgated by organizations like the American Heart Association and agencies like the CDC. Prestige, careers and lots of lots of money have been invested in making sure this particular perspective is reality; enough said.
What is currently clear is that arbitrarily reducing sodium consumption (particularly at or below the 1.5 g per day recommended by such aforementioned groups) does not clearly benefit everyone; and in fact may be detrimental. The absolutions on sodium consumption will hopefully go the way of the recent dietary cholesterol recommendations. Although it took decades of solid scientific research and heroic efforts by those willing to wear the black hat; the myth of a straightforward relationship between dietary cholesterol consumption and blood cholesterol levels has been exposed to the light of day. In 2015, these guidelines were eliminated.
But Dr. Frieden nailed several points worth their salt. As he notes, “High blood pressure disables and kills.” This is true. However, the link between a reduction in salt consumption and a meaningful reduction in high blood pressure that translates into less disability and death is far from clear.
However, serendipitously he concludes that that:
Three-fourths of sodium in Americans’ diets comes from processed and restaurant food; consumers have too little control over their intake. It’s one thing to choose how much salt to add to your food when you eat. That’s your decision. It’s another to live — or die — because of decisions made by those who formulate your food before it gets to your table.
When the food industry reduces sodium in restaurant and processed foods, it puts the decision in your hands — where it belongs.
And because God loves fools, drunks, little children and apparently the CDC; this reduction in processed food is where we can agree in practice, if not in principle. The highly processed, preserved, prepackaged and prepared foods that constitute the bulk of the modern Western diet are major source of unwanted sugars and additives. Many of these additives (ironically in the form of sodium compounds) can have significant debilitating effects on our health both directly and indirectly. In it addition to the direct effects of consumption upon our metabolism and physiology that can be seen for example with excessive fructose (found in high fructose corn syrup) intake; there can be indirect effects.
We are just beginning to discover that while compounds may not interact directly with the human elements of our gastrointestinal tract, they can debilitate our gut microbiome. These changes can predispose us to obesity, diabetes and varying degrees of continuous, chronic inflammation that is at the root of so many of the disabilities and diseases we confront today.
The keys to the kingdom do not lie in vilifying a single compound or constituent. Rather, it lies in understanding the relationship between quantity, quality and food value. In our helter-skelter modern society where a serving of chicken runs the gamut from a reformulated nugget to a free range heritage breed bird; quality has become the arbitrator of paramount importance. Our science is finally beginning to support what great chefs have known all along; quality ingredients and quality technique make the difference in pleasure and taste. For while it may be the taste that lingers, it is the inherent quality of our foodstuffs that allow us to be around long enough to enjoy it.
References:
American Heart Association. (2013, April). Facts Million Hearts: Saving Millions of Lives by Working Together. Retrieved from www.heart.org: http://www.heart.org/idc/groups/heart-public/@wcm/@adv/documents/downloadable/ucm_450774.pdf
Fenster MD, M. S. (2014). The Fallacy of The Calorie: Why The Modern Western Diet is Killing Us and How to Stop It. Virginia Beach, Va: Koehler Books.
Frieden, T. (2015, May 13). Too much salt is still unhealthy. The Washington Post, pp. http://www.washingtonpost.com/opinions/too-much-salt-is-still-unhealthy/2015/05/13/a502905e-f8a8-11e4-a47c-e56f4db884ed_story.html.
Mc Carron, D. A. (2000). The dietary guideline for sodium: should we shake it up? Yes! The American Journal of Nutrition, 71(5):1013-1019.
Zaraska, M. (2015, May 4). Pass the salt, please. It’s good for you. The Washington Post, pp. http://www.washingtonpost.com/national/health-science/we-eat-a-lot-of-salt-but-scientists-say-there-are-good-reasons-for-that/2015/05/04/69ff7058-c806-11e4-a199-6cb5e63819d2_story.html.
