Is Salt Really So Bad for You?
September 12, 2011, By Avery Hurt 0 comments
We've all been told for quite a while now that we should reduce our intake of salt. And so we resist the salt shaker at dinner, and we read food packages at the grocery store to find out how much sodium they contain. Well, this will probably come as a surprise to many of you, but the science behind the advice to eat less salt is somewhat inconsistent—and always has been. Nothing new here. What is new is that a few of the experts are rethinking their advice about salt. But don’t order those fries with extra salt just yet. First, let’s see what’s up and what’s not.
Back in May, a group of European researchers published a study that found, contrary to current wisdom, the less salt the study subjects had eaten, the greater their risk of dying from heart disease. (This study was not the first to suggest this result). Not long after, in July, the "American Journal of Hypertension" published a meta-analysis of several studies on salt and heart disease and concluded that while cutting salt did seem to lower blood pressure slightly in some subjects, there was little or no evidence that cutting salt actually lowered risk of heart disease. According to the researchers who did the meta-analysis, previous trials on the effects of salt on heart disease risk have been too small to provide any strong conclusions about the benefits (or lack thereof) of cutting back.
These studies have created a bit of ballyhoo in the heart-health community in the past few months, but questions about the dogma on salt are not at all new. Back in 1988, Intersalt, an international study testing the effects of salt intake on blood pressure, found that there was little or no relationship between increased sodium intake and increased blood pressure. The results from Intersalt actually showed that the group that ate the most salt had a slightly lower median blood pressure than the group that ate the least.
Much of the logic behind the theory that too much dietary salt is bad for the heart is based on epidemiological evidence showing that people who live in cultures with high salt consumption (such as Japan) tend to have high blood pressure and more strokes. However, there is not much evidence showing that within a given population blood pressure and strokes are higher in people who eat a lot of salt. The contributing factor could be genetic—or it could be due to something else altogether.
There certainly have been studies that show a connection between high blood pressure and eating too much salt, but the evidence is anything but robust. The whole thing is made even more complex by the fact that people vary wildly in their response to salt (elderly people and some African-Americans seem to be especially sensitive to salt—humans make such messy study subjects) and that cutting back on salt can trigger the body to produce substances that increase blood pressure.
