The stringent low-salt guidelines were based on a guess: we essentially gambled that the small benefits to blood pressure that we see in some patients would extend to large benefits for the whole population. And while taking that gamble, we glossed over the most important point: why salt may increase blood pressure in some people but not in others. Had we focused on that, we would’ve realized that fixing the underlying issue—which has nothing to do with eating too much salt—completely fixes one’s “salt sensitivity.” We also presumed that blood pressure, a fleeting measurement known to fluctuate depending on many health factors, was always impacted by salt. And because of that baseless certainty, we presumed that overconsumption of salt would logically result in dire health outcomes, such as strokes and heart attacks. Our mistake came from taking such a small sample of people—unethically small!—and wildly extrapolating their benefits from low-salt eating without ever mentioning the risks. Instead, we focused on those extremely minuscule reductions in blood pressure, completely disregarding the numerous other health risks caused by low salt intake—including several side effects that actually magnify our risk of heart disease—such as increased heart rate; compromised kidney function and adrenal insufficiency; hypothyroidism; higher triglyceride, cholesterol, and insulin levels; and, ultimately, insulin resistance, obesity, and type 2 diabetes. Perhaps most illustrative of this willful disregard for risk is the case of heart rate. Heart rate is proven to increase on a low-salt diet. This harmful effect occurs in nearly everyone who restricts his or her salt intake. Although this effect is documented more thoroughly in the medical literature, no food ad or dietary guideline says, “A low-salt diet can increase your risk of elevated heart rate.” And what has a bigger impact on your health: a one-point reduction in blood pressure or a four-beat-per-minute increase in heart rate? (In chapter 4, I’ll take a closer look at what these metrics mean and I’ll let you decide.) If our bodies allowed us to isolate each of these risks, we might be able to say for certain that one or another is most important. But when you combine all of the known dangers of salt restriction, it’s easy to see that the harms far outweigh any possible benefits. In other words, we’ve focused on just one metric that might change with a low-salt diet—blood pressure—but completely disregarded all the other harmful effects in the process.
One of the more contentious books in recent times that goes against the grain of what is conventional wisdom. Essentially, the main premise of this book is that salt is not as bad as we think it is for our health, and that sugar does way more harm. There has been many back-and-forth between health experts on this book on online forums and proves how complex nutrition is, and how each of us can react to nutrition in different ways.
In this excerpt, the main idea that the author is trying to convey is that demonisation of salt mainly came from a rather tenuous effect, on how reducing sodium lead to small decreases in blood pressure. The conclusion that salt is bad for you was drawn based on this, and other factors were ignored.
