Want to reduce your risk of high blood pressure? Eat less salt. For years, this has been the admonition of doctors, dietitians, and governmental health organizations. And why would it not be?
If eating less salt reduced a persons risk for high blood pressure, the incidence of cardiovascular disease, including heart attacks and strokes, which are related to high blood pressure, would be greatly reduced.
Unfortunately, the eat-less-salt recommendation is misguided and may cause more harm than good.
Sodium is an essential nutrient that is required for fluid regulation, nutrient transport, and blood pressure regulation. In other words, if we don’t get a minimal amount, we die. The major source of sodium in the diet comes not from the salt shaker, but from the added salt in processed foods.
While “sodium” and “salt” are commonly used interchangeable, sodium is only a component of salt. Salt is composed of 40 percent sodium and 60 percent chloride.
Today, Americans consume 3.4 grams of sodium, or 8.5 grams of salt, a day; much more than the amount recommended by health authorities.
The current federal Dietary Guidelines for Americans recommend that Americans consume no more than 2.3 grams per day of sodium — about the same amount in a teaspoon. The American Heart Association has a more strict guideline of consuming less than 1.5 grams a day for general health and disease prevention.
The evidence to support these recommendations, however, are far from persuasive.
Sodium and Blood Pressure
A 2016 meta-analysis looked at how salt intake affected cardiovascular disease outcomes in individuals with high blood pressure and normal blood pressure.
Researchers analyzed data from four studies which compared more than 133,000 people from 49 countries for more than four years. The people were about evenly split between people with and without high blood pressure.
It was found that people with high blood pressure tended to have more of a sensitivity to sodium. Those with high blood pressure had an increase of 2.1 mm Hg in blood pressure for each additional gram of sodium compared to 1.2 mm Hg in people without high blood pressure.
They also found that people with high blood pressure who consumed more than seven grams of sodium per day had significantly greater rates of cardiac events, such as strokes and heart attacks, and deaths than those who consumed four to five grams per day.
Those with normal blood pressure consuming more than seven grams per day, however, had no increased risk compared to those who consumed four to five grams per day.
That is, consuming too much salt appears to increase a persons risk for poor health outcomes for people with high blood pressure. But this concern isn’t seen in people with normal blood pressure.
Too Little Sodium Can Be Harmful
The habitual high salt consumption and hypertension have been linked for more than a century.
There is good evidence that reducing salt intake in people with high blood pressure who consume an excessive amount (more than seven grams) is a good idea.
But current evidence doesn’t support the idea that increased salt consumption in people with normal blood pressure makes a significant difference.
Plus, the numerous public health initiatives to reduce sodium intake may do more harm than good, especially in the absence of clear scientific evidence demonstrating benefit.
What we do know is that staying physically active, consuming a diet rich in fruits and vegetables, maintaining a healthy weight, and abstaining from heavy alcohol consumption are more impactful for improving health outcomes — including lowering of blood pressure — than consuming bland french fries.