The sodium story is almost identical to the fat story. For the last five decades or so, we’ve been told to decrease our sodium intake to prevent high blood pressure and cardiovascular risks. However, this message has overshadowed a fact that the entire medical field agrees on: we need salt to survive. This week, we’ll discuss the sodium myth, where it came from, and how we should manage our sodium intake!
First, let’s start off by mentioning that salt sensitive hypertension does in fact exist. This means that an increased consumption of salt can lead to high blood pressure, which can ultimately lead to cardiovascular risks like heart attack and stroke. The reality, however, is that the correlation between sodium intake and cardiovascular risks is much more nuanced. And the study where this message originated from should not have led to overarching dietary guidelines for all Americans to cut back on salt.
Sodium is an integral electrolyte that our bodies need for a number of functions. Sodium balances the volume of fluid in our bodies, helps us regulate our body temperature, conducts nerve impulses, and enables our muscles to contract. While excessive sodium intake is not ideal for our health, neither is restricting our sodium intake. Low levels of sodium can lead to low energy and dizziness. It can also lead to more severe consequences like strain on the kidneys and adrenals, increased cholesterol and triglycerides, and a condition known as hyponatremia (low sodium in the blood).
So what is the sodium myth? The sodium myth is the idea that we should decrease our salt intake if we want to reduce our chance of heart attack and other cardiovascular issues. This myth became mainstream nutritional advice even though it was only based upon one study – the DASH-sodium study. This study was conducted between 1997 and 1999, and included 412 adult participants who were either pre-hypertensive or stage 1 hypertensive. The participants were divided into two groups: those who followed the DASH diet (healthy whole grains, clean protein, fruits, and vegetables) and those who followed the standard American diet. These groups were further divided into three groups based on different daily intakes of sodium: high intake (3300 milligrams per day), intermediate intake (2400 milligrams per day), and low intake (1500 milligrams per day). The study observed that blood pressure lowered significantly for individuals in both diet groups who had a lower daily salt intake. So what did the doctors and mainstream health media do with this evidence? They jumped on it, announced new dietary guidelines, and created a whole slew of new low-sodium products.
There are a number of problems with this study and the definitive message that came from it. In terms of the study itself, salt consumption was not an isolated variable. The individuals in the study changed their entire diet, so was it really the decrease in sodium intake? Or was it the fact that these individuals simultaneously also lowered their glucose intake? Since this study was conducted, there has been a plethora of new evidence with counterclaims. For example, a meta-analysis of seven studies involving a total of 6,250 individuals in the American Journal of Hypertension from 2011 found no strong evidence that cutting salt intake reduces the risk for heart attacks, strokes, or death in people with normal or high blood pressure.
The truth is that too much of anything can be a bad thing – including excessive salt consumption. But we shouldn’t necessarily blame the salt shaker itself! What we should be wary of is the excessive amounts of salt that is hidden in foods of the standard American diet. While about 15 percent of the sodium we consume is naturally occurring in food, and we add about 10 percent while cooking or at the table, 70 percent of the sodium we consume is added by food manufacturers and by restaurants – and that’s the problem.