Most people accept as gospel the nutritional limits set by government organizations. So, when the Centers for Disease Control releases a report saying that 89 percent of Americans are consuming almost twice the daily recommended limit for sodium, we tend to pay attention. In last week’s Morbidity and Mortality Weekly, CDC researchers found that adult men and women in this country are eating about 50 to 100 percent more sodium than the recommended 2,300 mg daily limit, despite more than a decade of telling us to cut it out. And they suggest the way to finally get us to change our sodium munching ways is to convince food manufacturers to do it for us—to lower the content of processed foods. Considering we get on average 70 percent of our sodium from processed or prepared foods, this might reduce the amount of sodium we eat—might. But, the question that few seem to be asking is: will it make us healthier?
The problem is that, unlike salt and pepper, determining what constitutes a “healthy” sodium consumption range isn’t black and white. In fact, when you look at the levels of sodium consumed around the world, across cultures and economic levels, it becomes apparent that almost nobody on the planet is staying below the maximum sodium consumption levels set by the CDC and other health organizations. In fact, in 2014 The World Health Organization found that people in 181 out of 187 countries surveyed consume at least twice as much sodium as the WHO’s recommended 2 gram (or 2,000 mg) daily limit. So, is this a species-wide pandemic? Or is it possible that the government guidelines are just wrong?
Studies that have looked at populations’ sodium consumption, death from blood pressure-related diseases, and potassium intake have raised many questions in recent years. One particularly controversial study the Prospective Urban Rural Epidemiology (PURE) published in the New England Journal of Medicine in 2014 looked at the urine samples of 101,945 people in 17 countries to estimate sodium and potassium consumption. Shockingly, the PURE study found that “sodium intake between 3 g per day and 6 g per day was associated with a lower risk of death and cardiovascular events than was either a higher or lower estimated level of intake.” That is, people consuming between 3,000 mg and 6,000 mg of sodium a day were the least at risk to suffer a stroke or heart attack—in the low end that’s 700 more mg than the maximum recommended sodium intake by the CDC. A 2014 Danish metanalysis came to a similar conclusion, finding that people who consumed between 2,700 and 5,000 mg of sodium were least at risk for “all cause death” or death from cardiovascular disease events.
Emerging research is showing that sodium’s connection to cardiovascular risk, unlike salt and pepper, is not black and white. In the PURE study, for example, researchers found that high sodium excretion was more strongly associated with increased blood pressure if a person had lower potassium excretion. One French study that found sodium consumption was “statistically insignificant in relation to blood pressure,” did find that higher levels of fruit and vegetable intake—items high in vitamins like potassium—was shown to significantly lower blood pressure. More disturbingly, research—including a report from the Institutes of Medicine found that consuming less than 1,500 mg of sodium a day could be dangerous for certain at-risk population.
Even if getting people to consume less than 2,300 mg of sodium a day would result in net benefits, it’s not clear that efforts by the CDC would even be successful. The Brits tried this and claim to have reduced blood pressure nationwide and thus seen fewer cardiovascular events (but it’s not all that clear the decline is a result of Brits reducing their sodium intake by about 550 mg a day or if it’s due to other trends already underway—such as the falling rate of tobacco use in the UK) but clinical research has shown that “sodium appetite” is, at least in part, subconscious and driven by physiological needs. For example, in a 2013 study researchers looked at post-workout sodium consumption for those given a sodium tablet versus those given a placebo. The placebo group ate almost 300 mg more than the sodium-tablet group in their post workout meal.
What does all this mean? Well, if you’re consuming between 2,000 and 5,000 mg of sodium a day—like virtually everyone on the planet—the experts just don’t know how or if small reductions would affect cardiovascular risk. Certainly, if you’re consuming more or less than that or you’re in a high risk group, it’s worth talking to your doctor about your vitamin and mineral intake. But it is far too soon, too dangerous, and wasteful for governments to spend millions of dollars trying to change salt consumption patterns of entire populations.