- Disease Remedy
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These days, we seem especially prone to pepper salt with questions, or rather, to pepper one another with questions about salt. How much is too much? Is it possible to have too little? Is it really “generally recognized as safe,” and should the Food and Drug Administration regulate it as such? Or, should the FDA be obligated to acknowledge salt’s potential perils?
Before addressing the answers to the above, it is of interest to note that the current salt shakedown is a significant departure from all of prior history, which may be divided into two basic epochs with regard to sodium: wet, and dry.
The origins of life on this planet were, to the best of our knowledge, in the sea. The sea is salty, of course, and it was salty back then as well. Sodium was thus abundantly available to sea creatures, all of whom of necessity have mechanisms to ingest both water and salt, and excrete or secrete the excesses. Adapted to life in brine, fish are neither prone to sodium deficiency, nor to harms of sodium excess. That, then, was the wet period – and still is for the creatures that call the oceans home.
But when some distant ancestor of us all had the bright idea to poke its head out of the water, look around and climb out, the dry era began. Terrestrial creatures of most varieties have blood that is, up to a point, compositionally reminiscent of the sea that spawned us all. Among the many noteworthy features of blood plasma is a fairly high concentration of sodium.
In our own species, sodium plays many crucial roles vital to health. The mineral is prominently involved in the regulation of our blood volume and pressure, a point to which we will return. It is transported through ion channels that traverse the membranes of our nerve cells, making sensation and motion possible. As a result of its many vital roles, sodium is regulated by the body within a very narrow range of concentrations. Either too much or too little is toxic to us. A number of medical conditions – notably a rather common one called the syndrome of inappropriate antidiuretic hormone, and medical treatment in general – are associated with the potential for low blood sodium, or hyponatremia. We guard against this carefully in hospitalized patients by monitoring blood electrolytes closely. Hyponatremia, if uncorrected, can progress to seizures, coma and death.
All of this is to highlight the fact that for terrestrial creatures, salt has historically been at a premium. We need it, and it is (or was until recently) rather hard to get up here. For this reason, many animals will travel considerable distances to get to a salt (mineral) lick. In our own case, the value of salt has left an indelible imprint on our culture, and our lexicon. The city of Salzburg, Austria, was at its origins a commerce center for salt, and is named accordingly. The word “salary” comes directly from the Latin name for salt, and originally referred to the payment of Roman soldiers with vouchers for its purchase.
So, for a very long time, sodium was everywhere around us, and of no particular concern. Then, for another rather long time, sodium was stored within us, hard to find outside, and therefore quite precious. And then there is now.
In the modern era, the prevailing concern has been excessive salt intake, generally a byproduct of the value of salt in food preservation and processing. Salt has long been used as a preservative (think: pickling), and confers palatability as well. Before we relied so heavily on a processed food supply, these attributes were advantageous. Now, our food comes to us overwhelmingly in bags, boxes, bottles, jars and cans – and the addition of sodium is all but universal. As a result, the average American consumes roughly 3,400 milligrams of sodium daily, as compared to a recommended upper limit of 2,300 milligrams. As an easy rule of thumb, 2,300 milligrams of sodium in a prototypical diet of 2,000 calories daily is just a bit over 1 milligram of sodium per calorie. We are routinely overshooting that mark by 70 percent!
That excess is not of our own doing, and has little to do with the salt shaker. Roughly 75 to 80 percent of the salt in the typical American diet comes from food prepared for us by others, including both packaged goods and restaurant meals. Rather like sugar, salt is prone to a “more we get, the more we want” phenomenon, and figures in the manipulations of food that tend to maximize the calories we consume before running up the white flag (or napkin). This, of course, is bad for our waistlines and public health – but good for the profits of Big Food.
There has thus long been a dedicated focus in medical circles on sodium reduction in our diets. Of late, though, that concern has been challenged by findings suggesting harms from too little sodium in the diet. In particular, several studies have suggested potential harms with sodium intake at the lower end of the recommended range, or 1,500 milligrams per day. This “reversal” of sorts resulted in prominent and widespread commentary in both the mainstream media and the medical literature.
I have weighed in on the topic before now as well, on more than one occasion, most recently almost one year ago today. My basic view now, as then, is that (a) prevailing intake of sodium is excessive whatever the right lower limit ought to be; and (b) overwhelmingly, our sodium comes to us from processed foods and meals which often aren’t very good for us for other reasons as well. The answer, then, is not to fixate on sodium or banish the salt shaker, but to eat a diet of wholesome foods in sensible combinations; rely less on highly-processed foods; and ideally, to prepare meals at home more often and depend a bit less on restaurant meals.
This, then, leads back to the current peppering of salt with new provocations. First, a large federally-funded study called SPRINT was just terminated early because blood pressure reduction beyond current standards was found to confer a significant survival advantage. This study was not about sodium, but rather about the treatment of hypertension. It relates just the same. The DASH trials showed us years ago that dietary sodium does, indeed, contribute directly to blood pressure levels, and that dietary change, including sodium reduction, can be used to treat the early stages of hypertension. In the official guidelines for the management of elevated blood pressure, so-called “therapeutic lifestyle change” is the first recourse.
Second, New York City just approved a requirement for warning labels on restaurant meals with excessive sodium content. Excessive in this case should not be very controversial; it refers to meals with more than 2,300 milligrams of sodium, or more than the total recommended daily intake for an adult. Some meals cited provide more than twice that amount.
That, then, is the current reality, and related priorities. While it is certainly possible to consume too little sodium, and while there are legitimate doubts about the optimal low-end for the recommended intake range, most of us consume far too much from a food supply that routinely dishes out a day’s worth of sodium or more in a single meal. Concerns about deficient intake are largely hypothetical; excess is the present, and rather clear danger. The danger is clarified by the new research suggesting that deaths from heart attack and stroke go down with blood pressure reduction beyond the current norms of medical practice.
A shift to a less processed diet, and a greater reliance on foods direct from nature and home-cooked meals, is the best response. That will reliably dial down sodium intake while improving overall diet quality, something fixation on any given nutrient tends not to do. The risk of getting too little sodium from a diet of wholesome foods in sensible combinations is, if real, too remote to warrant any concern.
In general, we would benefit from lower blood pressure levels than tend to prevail. In general, we would benefit from lower sodium intake levels than tend to prevail. In general, we would derive both of these benefits, and more besides, from a lower intake of highly-processed foods, fast food and restaurant meals of uncertain composition.
Despite the peppering of new questions about sodium, in other words, the answers remain rather simple and stable. That’s how it all shakes out for me.