Sodium, Hiding in Plain Sight

JANE E. BRODY
April 1, 2013,
The New York Times

A new report, prepared by experts from three leading universities, projects that a small, steady reduction of sodium in the American diet could save up to half a million lives over the next decade. And a more rapid reduction could save even more lives — as many as 850,000.

The Finns have already proved this projection. As described last month in The New England Journal of Medicine, since the early 1970s, when Finland launched a national campaign to reduce salt intake, daily consumption has dropped by 3,000 milligrams a day in men and women, with a corresponding decline in death rates from stroke and coronary heart disease of 75 to 80 percent.

In the last decade or so, many food producers have introduced low-sodium or reduced-sodium versions of popular products, including soups, vegetables, fish, sauces, cereals, nuts, dips and even chips. But Americans still consume far too much sodium — a third more, on average, than the amount recommended for an otherwise healthy person and more than twice the amount recommended for people with high blood pressure, cardiovascular disease or kidney disease.

Sodium is an essential dietary element, but a mere 200 milligrams a day is all one needs for good health. The average American, however, takes in 3,300 milligrams daily, primarily from salt added to foods prepared commercially and in restaurants.

The federal Dietary Guidelines for Americans recommend a maximum of 2,300 milligrams of sodium daily — the amount in one teaspoon of salt — for an otherwise healthy person. The guidelines, and the American Heart Association, recommend an even lower limit, 1,500 milligrams daily, for about 60 percent of American adults: those already afflicted with ailments adversely affected by sodium, African-Americans (who are more susceptible to high blood pressure), and everyone age 51 and older.

Too much sodium in the diet causes the body to retain water, placing an added burden on the heart and blood vessels. The new report, published in the journal Hypertension, projects that 280,000 to 500,000 lives would be saved by a 40 percent reduction in sodium intake, to about 2,200 milligrams a day, over 10 years. An instantaneous reduction, to 1,500 milligrams, could avert between 700,000 and 1.2 million deaths in 10 years, the experts calculated.

These projections, based on computer simulations and models, were developed by research groups from the University of California, San Francisco; Harvard Medical School; and Simon Fraser University in British Columbia.

The researchers used three different methods to assess the benefits of sodium reduction and were struck by how similar the projected benefits turned out to be. One method was based on a randomized, controlled clinical trial of sodium reduction among men and women followed for 10 to 15 years.

A second method assessed cardiovascular risk indirectly based on the blood pressure effects of lowering sodium combined with drug therapy. And the third method relied on population studies of sodium reduction and resultant deaths from cardiovascular disease, stroke and all causes.

“No matter how we look at it, the story is the same. There will be huge benefits in reducing sodium,” said Pamela Coxson, a mathematician at the U.C.S.F. Center for Vulnerable Populations.

Dr. Kirsten Bibbins-Domingo, the director of the center and senior author of the new report, said in an e-mail that “if you lower sodium in your diet, your body starts to expect food to taste less salty, and that becomes the normal flavor of food. Lower-sodium diets down-regulate our salt taste receptors in about six weeks.”

Salt is just one common dietary source of sodium. Others include monosodium glutamate (MSG), baking soda, baking powder, disodium phosphate and other compounds with “sodium” in their names.

Still, salt — sodium chloride — is the prime offender. About 80 percent of the salt in the American diet, however, is introduced in food factories and restaurant kitchens. Ten types of foods contribute more than 40 percent of the sodium consumed by Americans, according to the Centers for Disease Control and Prevention.

The leading source is not a food that tastes especially salty, like pretzels or anchovies. It is breads and rolls, primarily because so much more of them are consumed than the other nine main sources of sodium: cold cuts and cured meats, pizza, poultry (often infused with salt water), soups, sandwiches, cheese, pasta dishes, meat dishes and snacks.

The good news is that the marketplace is now replete with better choices, including many foods with less sodium than others and low-sodium or reduced-sodium versions of traditionally salty foods. It pays to check the nutrition information on food labels (and, in the case of fresh poultry and pork, the ingredients lists) and choose products with less sodium.

Analyses by the Department of Agriculture and data from manufacturers show very wide ranges in sodium content of common products. Three ounces of deli or packaged turkey breast may contain anywhere from 450 to 1,050 milligrams of sodium. A cup of canned chicken noodle soup can have as little as 100 milligrams or as much as 940 milligrams of sodium. And a cheeseburger at a fast-food restaurant can have 710 milligrams or 1,690 milligrams of sodium.

Be aware of the current trend to infuse fresh poultry and meats with salted water. There are no nutritional labels on these foods in supermarkets, but the packaging should note whether salt water has been added. A four-ounce package of fresh boneless, skinless chicken breast may contain 40 milligrams of sodium or as much as 330 milligrams.

Even among salted snack foods, some choices are better than others. One of my favorites is lightly salted roasted peanuts. I like snacks with some salt but not too much, so I purchase both salted and salt-free mixed nuts and combine the two.

In a national public-private initiative coordinated by the New York City Department of Health and Mental Hygiene, a number of major companies have already achieved gradual reductions in salt in their products, with no untoward effect on sales, Dr. Bibbins-Domingo said. “If all companies take this approach, no company is at a disadvantage,” she said.

In home-cooked meals, there are myriad herbs, spices and peppers that can enhance the flavor of foods and reduce the need for salt. Fresh herbs add more flavor than dried ones, although they are more expensive and less convenient. (You might try growing rosemary and thyme on a sunny windowsill.) Or for a real flavor boost, add a tangy vegetable, like mustard greens, to your favorite recipe.

For 60 recipe ideas and a wealth of information about sodium and health, see the new book “Eat Less Salt,” by the American Heart Association.