Sodium and Other Nutrients Important to Blood Pressure

by Food and Drug Administration (FDA)

For years, consumers watching their sodium intake have had to plod through ingredient lists on many food labels like high school students through a Shakespearean play. They had to read a lot of unknown words and then do plenty of guessing.

Aiming to get some idea of a food's sodium content, consumers knowledgeable about sodium-restricted diets looked for names like sodium caseinate, monosodium glutamate, trisodium phosphate, sodium ascorbate, sodium bicarbonate, sodium stearoyl lactylate, and other sodium-containing ingredients, including salt (sodium chloride).

It wasn't easy, and it wasn't always accurate. Elizabeth Adams of Highland, Md., can vouch for that. She started to limit her sodium intake 23 years ago. She recalled spending "a long time" in grocery stores reading ingredient lists and looking for nutrition information, which then was voluntary and, until recently, appeared on only about 60 percent of food labels.

"I got to the point where I didn't buy a food unless it had only one ingredient or carried nutrition information," she said. "I had no idea otherwise how much sodium the food had in it."

Resorting to such measures will no longer be necessary for the nearly 50 million Americans like Adams who suffer from hypertension (high blood pressure) and the many others who want to reduce their risk for it. The food label they depend on to help monitor their sodium intake — and thus control their blood pressure — now must state how much sodium a food contains per serving and how the food fits in with their daily diet.

Label Changes

These requirements are the result of the Nutrition Labeling and Education Act of 1990 and regulations from the Food and Drug Administration and the U.S. Department of Agriculture. Under these regulations, consumers are seeing:

Nutrition information in bigger, more readable type on almost all packaged foods. It appears in the table headed "Nutrition Facts," which is usually on the side or back of the package. Nutrition information also will be available in stores near many fresh foods, like fruits and vegetables.

"% (percent) Daily Values," which tell consumers at a glance the levels of important nutrients in a food and how those amounts fit into a daily diet.

Serving sizes that closely reflect the amount people actually eat.

Strictly defined nutrient-content claims, like "low-sodium," "salt-free," and "rich in potassium." This means that when consumers see such claims, they can believe them.

Strict rules for using health claims, such as one that links low-sodium diets to a reduced risk of high blood pressure.

Sodium's Role

Some of the information — particularly that pertaining to sodium content — will be of special interest to people with high blood pressure.

Sodium has long been a major dietary factor in reducing the risk of, and controlling, high blood pressure. (For more on hypertension, see "High Blood Pressure: Controlling the Silent Killer," in the December 1991 FDA Consumer.) This role was reiterated as recently as January 1993 in the fifth report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure. The committee noted that numerous studies have shown that reducing sodium intake can reduce blood pressure.

What is a reduced sodium intake? According to Camille Brewer, a registered dietitian and nutritionist in FDA's Office of Food Labeling, therapeutic sodium-restricted diets can range from below 1,000 milligrams (mg) to 3,000 mg a day.

"American adults, on average, eat too much sodium — between 4 to 6 grams (4,000 mg to 6,000 mg) daily," she said. "Most people would benefit from moderately reducing their sodium intakes."

Brewer advises people who are considering a sodium-restricted diet to consult a physician, dietitian or nutritionist first.

Under FDA's food labeling rules, the Daily Value for sodium is 2,400 mg. (Daily Values are a new label reference tool. FDA established this value because it is consistent with recommendations and government reports that encourage reduced sodium intakes.

Salt and other sodium compounds used in food processing are the biggest contributors of sodium to most people's diets, Brewer pointed out. (One teaspoon of salt has about 2,000 mg of sodium.)

These substances are used in food processing for preserving, flavoring and stabilizing other ingredients, she said.

"That's why the ingredient lists of canned, frozen, and other processed foods often contain the names of so many sodium compounds," she said.

Also, kosher beef, lamb and chicken have salt added.

Sodium also is present naturally in some foods, such as milk, cheese, meat, fish, and some vegetables.

Alternatives to High-Sodium Foods

Low-sodium alternatives to some foods are shown in table format as well as in a chart for browsers that do not support tables.

Weight Reduction

Label information about fat, calories and fiber also will be important for people with high blood pressure who are overweight. These are the nutrients of most concern to those trying to lose weight or control it.

Body weight, like sodium intake, often closely correlates with blood pressure: As weight goes up, blood pressure frequently does, too. If weight is reduced, blood pressure often goes down.

About the Author

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FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.