Why it's harder than you think to pass up 'deadly' salt

Houstonian Diane Fries did what any conscientious patient would do when her doctor told her she had high blood pressure: she got rid of her salt shaker and stopped eating foods obviously high in sodium.

But the change had little effect. The problem, Fries eventually learned, is the salt in processed food and restaurant cuisine, the unsuspected ingredient in everything from salad dressings to breads to cheeses. When she began paying attention to it, her blood pressure went down.

"There's so much hidden salt in food people aren't aware of," said Fries, a lifelong Texan who describes herself as having grown up on fried foods and salt. "You just don't think of it normally."

Health officials are trying to change that. The American Medical Association has launched a public-awareness campaign about the hidden salt in people's diets and the Food and Drug Administration is mulling regulating what one consumer advocacy group dubbed "the deadly white powder."

The goal is to cut sodium intake by half over the next decade, which health officials say could save as many as 150,000 lives annually. One official says the death toll from America's excessive salt consumption is the equivalent of "a jumbo jet with more than 400 passengers crashing every day of the year, year after year."

'Sodium overload'

The matter is not without controversy. Some people are more sensitive to the harmful effects of salt than others, and there's no real way to figure out if you're one of them. Food manufacturing officials, who say there are no great alternatives to salt in processed foods, argue there isn't evidence to justify a campaign against the simple mineral. They call for a voluntary approach.

It is almost impossible to prepare a meal without salt — it preserves food by inhibiting bacterial growth, offers technical advantages in the kitchen such as raising the boiling point of water, and, as one of the four taste categories, adds flavor or heightens existing flavor.

But health officials say there's an indisputable link between sodium and hypertension, which often doesn't cause obvious symptoms, but if left untreated can lead to heart attack and stroke. Of the 65 million Americans believed to have high blood pressure, about one third aren't aware of it.

"What is clear is that people are getting a sodium overload," says Dr. James Rohack, a Texas A&M Health Science Center cardiologist. "And in large population studies, reductions in that overload have reduced blood pressure, saving lives."

Salt's role in history

Suspicions about salt are not new. In 2,500 B.C., physicians in China warned patients that if they used too much, their "pulse" would harden. Today, doctors say bodies react to sodium by holding onto more water. That extra water increases the volume of blood flowing through the blood vessels, which in turn raises blood pressure.

For such a simple substance, common salt has had a complex past. Once scarce, it was considered as precious as gold, valued as an agent to clean, dye, soften leather and bleach. It also came to be recognized as an essential part of people's diets, necessary for many body functions: fluid balance, nerve conduction, blood clotting and muscle contraction.

How much is too much?

But the amount needed is minor. The average American now consumes about 4,000 milligrams of sodium a day, up from about 2,300 milligrams in the early 1970s, the last time it matched the amount health officials say can be safely ingested.

That 2,300 milligrams of sodium, equivalent to a teaspoon, is an upper limit, say experts. An adequate intake is 1,500 milligrams for people ages 9 to 50; 1,300 for people 50 to 70; and 1,200 for those over 70.

The majority of the excess sodium in modern diets — 77 percent — comes from processed foods and restaurant cuisine. It can turn up in the least expected places. A Starbucks cheese danish contains 750 milligrams. Chipotle's vegetarian burrito contains 2,270 milligrams.

Currently, the nutrition label on packaged foods says how much salt is in a serving. But it doesn't explicitly note whether the amount is particularly high. The AMA says any food containing more than 480 milligrams of sodium per serving should be considered a high sodium food.

"We'd like the FDA to require warning labels on food products, a simple system like traffic lights," says Dr. Stephen Havas, the AMA's vice president for science, quality and public health. "High sodium content would get a red light, medium would get a yellow and low would get a green."

The FDA last looked at regulating salt in 1982, when it rejected the idea of revoking its "generally recognized as safe" status. At the time, it said it would be "extremely difficult" to prescribe and enforce fair limits that would be safe for all. It is taking input in the matter again now at the request of the AMA and the Center for Science in the Public Interest.

Worldwide efforts

Food industry officials argue that studies have shown salt reductions bring only modest reductions in blood pressure. That is perhaps because salt affects people differently — the largest reductions were among those with high blood pressure.

Although some food companies have voluntarily lowered sodium content — ConAgra estimates that in the past four years it's removed 2.8 million pounds from items such as Chef Boyardee and Marie Callender's — but others have done just the opposite. One survey found that between 1994 and 2004, the sodium content of food increased by 6 percent.

In any event, the issue isn't confined to the U.S. The World Health Organization has called for world sodium reduction in processed foods, and countries such as Finland and Britain are well into campaigns. In the United States, the FDA is keeping its cards close to the vest.

"The docket will be open until March," said FDA spokesman Michael Herndon. "Beyond that, we can't speculate on any likely decision."

todd.ackerman@chron.com