June 8 2012
Last Sunday, the New York Times ran an important opinion piece by health writer Gary Taubes who wrote about the ongoing attempts to regulate salt. Taubes explained that the reason the eat-less-salt argument has been so controversial and difficult to defend is because the actual evidence to support it has always been so weak (emphasis mine).
While, back then [in 1998], the evidence merely failed to demonstrate that salt was harmful, the evidence from studies published over the past two years actually suggests that restricting how much salt we eat can increase our likelihood of dying prematurely. Put simply, the possibility has been raised that if we were to eat as little salt as the U.S.D.A. and the C.D.C. recommend, we’d be harming rather than helping ourselves.
WHY have we been told that salt is so deadly? Well, the advice has always sounded reasonable. It has what nutritionists like to call “biological plausibility.” Eat more salt and your body retains water to maintain a stable concentration of sodium in your blood. This is why eating salty food tends to make us thirsty: we drink more; we retain water. The result can be a temporary increase in blood pressure, which will persist until our kidneys eliminate both salt and water.
The scientific question is whether this temporary phenomenon translates to chronic problems: if we eat too much salt for years, does it raise our blood pressure, cause hypertension, then strokes, and then kill us prematurely? It makes sense, but it’s only a hypothesis. The reason scientists do experiments is to find out if hypotheses are true.
We've all experienced the ever-changing recommendations of public health officials when it comes to particular food items or ingredients. Several years ago when I was pregnant with my first child, I was told to avoid tuna fish and most fish for the whole of my pregnancy because of concerns about mercury. Turns out, the doctors were wrong. Today, doctors are actually worried that pregnant women aren't getting enough fish and the omega-3 fatty acids contained in fish that are so critical to a child's brain development. As such, doctors now recommend that women keep fish in their diet and are not told to avoid canned tuna. This of course, does nothing for my kid or my guilt at having cost my kid a few IQ points because I believed my doctor who was relying on the unsettled science on fish.
Similar hysterical have been made about eggs, beef, canned food, and other food items only to have the government do a big "my bad" when they change their mind about the matter. It looks like the newest research on salt may cause this same type of shift. Taubes explains:
With nearly everyone focused on the supposed benefits of salt restriction, little research was done to look at the potential dangers. But four years ago, Italian researchers began publishing the results from a series of clinical trials, all of which reported that, among patients with heart failure, reducing salt consumption increased the risk of death.
Those trials have been followed by a slew of studies suggesting that reducing sodium to anything like what government policy refers to as a “safe upper limit” is likely to do more harm than good. These covered some 100,000 people in more than 30 countries and showed that salt consumption is remarkably stable among populations over time. In the United States, for instance, it has remained constant for the last 50 years, despite 40 years of the eat-less-salt message. The average salt intake in these populations — what could be called the normal salt intake — was one and a half teaspoons a day, almost 50 percent above what federal agencies consider a safe upper limit for healthy Americans under 50, and more than double what the policy advises for those who aren’t so young or healthy. This consistency, between populations and over time, suggests that how much salt we eat is determined by physiological demands, not diet choices.
One could still argue that all these people should reduce their salt intake to prevent hypertension, except for the fact that four of these studies — involving Type 1 diabetics, Type 2 diabetics, healthy Europeans and patients with chronic heart failure — reported that the people eating salt at the lower limit of normal were more likely to have heart disease than those eating smack in the middle of the normal range. Effectively what the 1972 paper would have predicted.
It's important to remember that the FDA is moving forward with its plans to regulate salt. In May, the Food and Drug Administration released its 2012-2016 strategic plan which included a statement that the FDA would work to "reduce sodium content in the food supply." That proves that the FDA isn't reading the latest research. It simply isn't paying attention to the alarming evidence that shows lowering individual's salt intake can be dangerous. As Taubes explains, when the USDA and the FDA held hearings last year to discuss how to get Americans to eat less salt, proponents of salt regulations actually argued that the latest reports suggesting damage from lower-salt diets should be ignored.
But this simply shouldn't be ignored. As the latest research states, this isn't only a matter of unnecessary regulations, this is a matter of life and death. The science is out on salt...so should the government.