Less salt lowers blood pressure and disease.
It’s no surprise that cutting salt lowers blood pressure. That has been shown in studies that compare higher- versus lower-salt diets in both adults and children and in the DASH-Sodium study.1,2
“We tested the DASH diet and a typical American diet with three levels of salt,” says Frank Sacks, professor of cardiovascular disease prevention at the Harvard T.H. Chan School of Public Health.
“With or without the DASH diet, blood pressure dropped when people went from a typical 3,300 milligrams of sodium a day to 2,400 mg a day to 1,500 mg a day.”3
For example, in the Trials of Hypertension Prevention, some 2,400 people with prehypertension were randomly assigned to cut their sodium by roughly 750 to 1,000 mg a day or to follow general guidelines for healthy eating for 1½ to 4 years.4
Ten to 15 years after the studies ended, researchers found a 25 to 30 percent lower risk of heart attacks, strokes, and other cardiovascular events in the group that had cut salt.
“A decrease in sodium in the diet, even among those with only modestly elevated blood pressure, lowers the risk of cardiovascular disease later in life,” says investigator Nancy Cook, professor of medicine at Harvard Medical School.
Assume you’re sensitive to salt.
“There may be some individuals who are salt sensitive and who should reduce their salt consumption,” says the Salt Institute, which represents the salt industry.5
“Some people react to sodium more quickly than others,” says Stephen Havas, professor of preventive medicine at the Northwestern University Feinberg School of Medicine. “But 90 percent of people in this country develop hypertension, and the principal cause is exposure to excess sodium. So most people over time don’t do well with high salt loads.”
What’s more, adds Havas, “there is no predictor or test of salt sensitivity, so one has to assume that almost all of us are sensitive to long-term sodium exposure.”
That’s why expert panels recommend no more than 1,500 mg of sodium a day if you have high blood pressure or prehypertension. Everyone else should shoot for 2,300 mg a day. But “everyone else” is just 30 percent of U.S. adults.
It’s tough to cut salt on your own.
You can cut out the salt shaker, but most sodium comes from processed and restaurant foods.
“I’m a physician,” says Kirsten Bibbins-Domingo, professor of medicine at the University of California, San Francisco, “and it’s always striking to me how hard it is for my patients to cut salt.”
That’s because 75 to 80 percent of the sodium we consume is added to food before we open a package or walk into a restaurant.
So unless you make everything—including bread, crackers, cereal, soup, pizza, spaghetti sauce, salad dressing—from scratch, you can’t easily avoid the salt.
“You can take all the salty snacks out of your diet—the nuts and the chips and everything else—but much still remains,” says Bibbins-Domingo.
“So many patients come to me thinking they’ve made healthier choices, and they’re oftentimes consuming the same, if not more, salt.”
And restaurants make supermarket salt levels look low.
“People eat more and more in restaurants,” says Northwestern University’s Stephen Havas. “They have no idea how much sodium is in those foods.”
If food companies don’t meet the Food and Drug Administration’s proposed targets for cutting salt, the FDA should set limits and require warning labels on high-salt foods.
“We can’t just keep saying, ‘Let’s try a voluntary approach,’” says Havas. “Too many people are dying or becoming disabled.”
1 J. Human Hypertens. 16: 761, 2002.
2 Hypertension 48: 861, 2006.
3 N. Engl. J. Med. 344: 3, 2001.
4 BMJ 339: b4567, 2009.
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