Take the guesswork out of sodium restrictions

Nursing, Aug 2002 by Collins, Nancy

Teach your patient a few basic rules he can use to limit sodium intake every day.

Low sodium.. low salt... sodium free... no added salt.. restricted sodium. If you watch television or read magazines, you've been bombarded with these terms. And what about your patients who need low-sodium diets? Do you feel intimidated teaching them about their dietary restrictions? In this article, I'll help you sort out the confusion.

Essential mineral

Sodium is a natural component of most foods. An essential mineral, it has many important metabolic functions in the body. It plays a vital role in fluid balance, acid-base balance, maintenance of blood pressure and blood volume, cell permeability, and normal muscle excitability. Nutritionists estimate that adults need 500 mg/day of sodium to meet the body's needs.

A big source of confusion about sodium is its relationship to table salt, the source of most dietary sodium. Salt is commonly used as an additive in processing and preparing foods. Known as sodium chloride (NaCl), it contains equal parts of sodium and chloride, so added salt adds sodium. However, the words "sodium" and "salt" aren't interchangeable. Even if a food product contains little salt, it may still contain sodium.

Most Americans consume much more sodium than their bodies require. Adding salt to foods is often a habit; many people don't even taste their food before they do it. The average person consumes up to 6,500 mg of sodium per day, more than double the American Heart Association's recommended maximum of 3,000 mg/day

A sodium-controlled diet is part of treatment for several medical conditions, including hypertension, heart failure, cirrhosis, kidney disease, and conditions that cause fluid or sodium retention. If your patient is on cortisone or adrenocorticotropic hormone therapy, a sodium-controlled diet may help as well because these drugs cause fluid retention. A registered dietitian can help him learn what he must do to limit sodium intake, and you can reinforce what he learns.

How much restriction?

When a patient needs to follow a "low-sodium" diet, what must he do? Sodium restrictions cover a wide range, but generally fall into three categories:

Mild restriction means limiting sodium intake to approximately 3,000 to 4,000 mg(day. In health care facilities, this type of restriction is commonly called a "no added salt" or "NAS" diet.

Moderate restriction means limiting sodium to approximately 2,000 mg/day by consuming only foods labeled "low sodium."

Severe restriction calls for approximately 500 mg(day. Some restrictions include consuming lowsodium bread, limiting daily meat consumption to 5 ounces, and drinking distilled water. The dietitian can provide a list of foods to omit, such as sherbet, flavored gelatin, and certain vegetables.

When you're advising a patient how to restrict sodium in his diet, teach him not to rely on marketing hype. (For terms allowed by law, see Coming to Terms with Food Labels.) Instead, he should read food labels for sodium content and plan his intake for each day.

Paying attention to food labels isn't enough. Your patient also should become familiar with the many different sources of sodium in foods. Common ingredients that are high in sodium include monosodium glutamate (MSG), baking powder, baking soda, brine, sodium nitrate, sodium citrate, and disodium phosphate. Warn him that over-the-counter medications may contain sodium too. (See Sodium Content of Common Over-the-Counter Drugs.)

Practical pointers

To help your patient restrict his sodium intake, give him the following practical pointers:

Forget the saltshaker and develop a taste for other seasonings. Caution your patient about commercially available substitutes that replace the salt flavor. Many of these substitutes contain large amounts of potassium, which may also be restricted in people with medical conditions such as renal disease.

More desirable replacements for salt include herb mixtures, lemon wedges, lemon pepper, and fresh seasonings, such as garlic and onions. A typical herb blend contains basil, thyme, parsley, cloves, mace, black pepper, dried savory, cayenne pepper, and nutmeg. Many people have never tasted these flavors, so encourage your patient to experiment.

Avoid canned foods, cured and salted meats, and certain condiments. They're notoriously high in sodium. Large amounts of sodium are commonly used in processing canned foods, so fresh and frozen foods are a better choice. If your patient must use canned foods, tell him to look for low-sodium products. Cured and salted meats include ham, many lunch meats, hot dogs, bacon, sausages, herring, anchovies, and sardines. Condiments that are high in sodium include ketchup, barbecue sauce, soy sauce, salad dressings, and steak sauce.

For a severe sodium restriction, avoid shellfish and limit milk products. Shellfish such as lobster and crab are high in sodium. An 8-ounce glass of milk contains approximately 120 mg of sodium, so your patient may need to limit consumption to one glass a day or one cup of yogurt. He should eat only low-sodium cheese.