There’s been a lot of talk lately about limiting salt intake to improve your health, but the conversation isn’t new.
Experts have known since the first studies were published in the 1940s that significantly reducing sodium in the diet could lower blood pressure. The dangers of excessive salt have been known for so long that thousands of years ago Chinese noblemen would use large amounts to commit suicide.
Today, sodium excess remains a deadly threat. The average American consumes about 3,400 milligrams of sodium a day, more than double the 1,500 milligrams recommended by the American Heart Association.
Too much sodium increases the risk of high blood pressure and other major health problems. More than 76.4 million people in the U.S. have high blood pressure — one-third of the population. High blood pressure is known as the “silent killer” because its symptoms are not always obvious.
"Elevated blood pressure is the leading cause of preventable death worldwide and sodium is one of the leading causes of elevated blood pressure,” said Lawrence Appel, M.D. director of the Welch Center for Prevention, Epidemiology and Clinical Research at Johns Hopkins University in Baltimore, Maryland.
The body needs only a small amount of sodium (less than 500 milligrams) to function properly, although consuming this amount probably would leave a person short of meeting other nutrient requirements.
Sodium helps maintain fluid levels, send nerve impulses and affects muscle function. It is regulated in the body by the kidneys. If they detect too much sodium in the bloodstream, they can release the excess into the urine to be flushed away. But if the kidneys aren’t functioning properly or someone’s body is more sensitive to the effects of salt, more sodium stays in the bloodstream.
Because sodium naturally bonds to water, the extra sodium pulls water into the bloodstream, increasing the total amount of blood in the body. With more blood flowing through the blood vessels, blood pressure increases. It’s like turning up the water to a garden hose — the pressure in the hose increases as more water is blasted through it.
Over time, high blood pressure may overstretch or injure the blood vessel walls and speed the build-up of gunky plaque that can block blood flow. The added pressure also overtaxes the heart by forcing it to pump more blood through the body. High blood pressure is a major risk factor for heart attack, stroke, heart failure, kidney failure and peripheral vascular disease, according to the AHA.
“The most important reason to lower blood pressure is to prevent vascular damage over your lifetime. Even if you aren’t sensitive to salt now, you will be,” said Appel, who is also an American Heart Association volunteer. “If you’re in your 20’s, you think you’re immortal, but there’s nearly a 100 percent chance that you’ll develop high blood pressure by your 70s or 80s.”
The American Heart Association recommends people consume a maximum of 1,500 milligrams a day of sodium based on scientific evidence that it is the best approach for cardiovascular health while also providing an adequate intake of other important nutrients.
Some organizations suggest a goal of 2,300 milligrams a day. The larger point, however, is that Americans overindulge in sodium.
“There are so few people consuming 2,300 milligrams that it’s a great interim goal,” said Appel. "If everyone reduced their daily sodium intake to 2300, I would click my heels. If we got people to 1,500, I’d click twice.”
The prevalence of sodium in our food supply hampers widespread efforts to lower daily intake. More than 75 percent of the sodium consumed is from processed foods.
“Some food manufacturers add sodium because it’s what they’ve always done and they may be unwilling to risk changing the taste of the foods that consumers demand,” Appel said. “But taste is a sweet spot that can be moved.”
The American Heart Association’s Nutrition Committee Chair, Rachel Johnson, Ph.D., MPH, RD, FAHA, agrees.
Studies show that when people are given a lower sodium diet for a period of time, they begin to prefer lower-sodium foods and the foods they used to enjoy taste too salty."
The American Heart Association supports efforts that will bring the amount of sodium in the food supply down gradually. Ultimately, the association hopes to change the Food and Drug Administration’s regulatory status of sodium — currently, “generally recognized as safe.” Under that category, food manufacturers can add as much sodium to foods as they want.
Food labeling requirements being developed by the FDA are expected to require chain restaurants to disclose total calories – but not sodium – on menus and menu boards. However, the FDA probably will require that sodium content be provided upon request, along with the amount of saturated fat, cholesterol, total carbohydrates, sugars, fiber and total protein.
Some states and cities have already developed menu labeling requirements. Philadelphia requires sodium to be disclosed on menus and menu boards, as does California. Montgomery County, Maryland has recently proposed adding sodium content to menu information.
Such labeling requirements help consumers make informed decisions and can encourage restaurants to reformulate their menu items, according to the Center for Science in the Public Interest.
Awareness is an important strategy for making changes to your diet, Johnson said.
“For people who would like to reduce sodium intake, the first step is to start paying more attention to labels and substitute lower sodium versions of foods when possible,” she said.
- Processed Foods: Where is all that salt coming from?
- Eat Less Salt, a healthy lifestyle book
- A Primer on Potassium
Last reviewed 10/2013