Low-Sodium Diet

Definition

A low-sodium diet is a diet that is low in salt, usually allowing less than one teaspoon per day. Many conditions, including kidney disease, heart disease, diabetes, and hypertension require patients to follow a low-sodium diet.

Origins

Low-sodium diets have no single origin. Many hospitals and health centers have long recommended that people with diseases that are affected by sodium intake lower the amount of salt in their diet.

Description

The role of sodium

The majority of sodium consumed comes from sodium chloride (NaCl), better known as salt. Salt has many useful properties in food preservation. It helps to prevent spoilage by drawing the moisture out of foods. This helps to keep bacteria from growing in the food. It can also kill bacteria that are already growing on the surface of foods. Before refrigeration technology was developed, salting was one of the few methods available for preserving foods, such as meat, through the winter. Salt also dissolves into the electrolytes Naþ and Cl, which help maintain the right balance of fluids in the body, transmit signals through the nervous system, and cause muscles to contract and relax.

Ways to reduce salt intake

Research from 2017 suggests that average Americans get only 5% of the total salt intake from salt that is added at the table. Only 6% comes from salt that is added during cooking, and natural sources in food make up another 15%. At 77%, the majority comes from processed or prepared foods, with minimal amounts from other sources such as tap water, dietary supplements, or antacids. Many packaged meats, as well as canned and frozen foods, contain a surprising amount of salt. Salt is used heavily by manufacturers because it acts as a preservative, adds flavor to foods, helps to keep foods from drying out, and can even increase the sweetness in desserts. Soups are often especially high in salt because salt helps to disguise chemical or metallic aftertastes.

One of the best ways to reduce salt intake is to cut back on heavily processed and prepared foods. Hot dogs, sausages, ham, and prepackaged deli meats usually contain much more salt than freshly sliced lean meats, such as chicken or fish. Most canned vegetables, if preserved in brine, also have a much higher salt content than the same vegetables found in the fresh produce section. Information on frozen prepared meals should be carefully checked for the same reason, and canned soups usually contain much more salt than soups made at home. By reading the nutrition facts label on the side of commercially manufactured foods, consumers can determine how much sodium is in the food they are considering.

When choosing canned or frozen foods, people who wish to reduce their salt intake can often find a “low sodium” option. The U.S. Food and Drug Administration (FDA) sets legal standards for how much sodium can be contained in a product that is labeled “low sodium.” Products labeled as such may not contain more than 140 milligrams of sodium per serving, while products labeled as “reduced sodium” only need to contain 25% less sodium than the usual amounts found in those products. Very low sodium products contain 35 mg or less of sodium per serving.

KEY TERMS
Electrolytes—
Ions in the body that participate in metabolic reactions. The major human electrolytes are sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), chloride (Cl-), phosphate (HPO42-), bicarbonate (HCO3-), and sulfate (SO42-).
Hyponatremia—
An abnormally low concentration of sodium in the blood.
Low-salt foods—
Food products which contain not more than 140 milligrams of sodium per serving.
Mineral—
An inorganic substance found in the earth that is necessary in small quantities for the body to maintain health (e.g., zinc, copper, iron).
Reduced sodium—
Containing 25% less sodium than the usual amount found in that product.

Meals served in restaurants are also often high in salt. Most restaurant kitchens use a great deal of processed foods. They then sometimes add more salt because it is an inexpensive way to improve the taste. Many restaurants provide dietary information about their meals on posters, napkins, or cups rather than on menu boards or menus. Some restaurant chains even provide this information on their websites so that customers can decide on a low-sodium meal before visiting the restaurant. If this information is not available, dieters can use the same ideas for avoiding salt at the restaurant that they do at the supermarket. Salads and other foods made with fresh vegetables will usually have less salt than soups. Appetizers and meals with sauces should generally be avoided or have sauces served on the side.

Another time to reduce salt in the diet is when cooking or preparing meals at home. With the exception of baked goods, many recipes that call for salt do so only for taste, and it can be left out. By substituting herbs and spices for salt, the cook can avoid making bland food while still avoiding salt. When choosing a packaged herb or spice mixture, it is important to select one that is not itself high in sodium. Using the zest of a lemon or lime is another a good way to add flavor without adding salt. Artificial salt substitutes are available, but kidney patients should avoid these as they are usually high in potassium, another mineral that is regulated by the kidneys.

Sodium content of popular foods

Many people are unaware of just how much sodium is in some of the most popular foods. A low-sodium diet generally consists of 1,500 to 2,400 milligrams of sodium each day. Some foods contain almost half of this in a single serving. The following is a list of foods and the approximate amount of sodium in one serving of each of them.

Function

The low-sodium diet is designed to lower the amount of sodium that a person consumes. Although this is generally considered healthy for most Americans, a low-sodium diet is particularly important for people suffering from certain conditions and diseases.

For kidney patients, reducing sodium is important because the kidneys are no longer capable of effectively filtering sodium out of the body. If these patients do not reduce their sodium intake, the buildup of sodium will cause fluid retention, which can cause swelling in the lower extremities. A low-sodium diet will help to prevent this problem. For heart patients, a low-sodium diet is important to help reduce strain on the heart. Excess sodium in the bloodstream means that excess fluid is kept suspended, which increases the volume that the heart must pump.

Benefits

Low-sodium diets provide benefits for people suffering from many different diseases and even for those who are not. A diet that is low in sodium can help to reduce blood pressure and the risk of heart disease and stroke. People with a family history of heart problems, people of African descent, smokers, those who frequently drink alcohol, people who are overweight or do not exercise regularly, and people who live with a lot of unmanaged stress are all at higher risk for increased blood pressure and should consider a low-sodium diet. For heart disease patients, a low-sodium diet can be part of a plan to reduce their blood pressure and reduce the strain on their heart to slow the progress of their conditions and prevent future problems. For kidney patients, a low-sodium diet is necessary to prevent fluid retention.

Precautions

Individuals thinking of significantly altering their regular diets should talk to their physicians. Each person has different dietary needs, which should be considered. In general, moderately lowering sodium intake is considered safe for most people. Dieters should be careful to not severely and abruptly increase their level of exercise and fluid intake while severely and abruptly lowering their sodium intake to avoid hyponatremia.

Risks

The risks of following a low-sodium diet are very low. Many experts believe that most Americans could benefit from following a low-sodium diet, even if they do not yet suffer from any of the conditions that might require them to do so. Most Americans consume between 3,000 and 5,000 milligrams of sodium per day, and a low-sodium diet reduces this to a healthier level of between 1,500 and 2,400 milligrams per day. Because the physiological requirement for sodium for adults is only 500 milligrams daily, there is little danger that individuals following low-sodium diets will consume so little sodium that it will endanger their health.

Some athletes and others who exercise frequently and ingest very little sodium yet drink a lot of water may be at risk of hyponatremia, a condition that occurs when the body does not have enough sodium. Though rare, low sodium levels can cause headache, nausea, lethargy, confusion, muscle twitching, and convulsions.

Research and general acceptance

QUESTIONS TO ASK YOUR DOCTOR

See also Coronary heart disease ; Diabetes mellitus ; Electrolytes ; Heart-healthy diets ; Renal nutrition ; Sodium ; Weight Watchers .

Resources

BOOKS

American Heart Association. Low-Salt Cookbook. 4th ed. New York: Harmony, 2016.

Gazzaniga, Donald A., and Maureen A. Gazzaniga. The No-Salt, Lowest Sodium Light Meals Book. New York: Thomas Dunne Books, 2013.

Larsen, Laura, editor. Diet and Nutrition Sourcebook. 5th ed. Detroit, MI: Omnigraphics, 2016.

Nix, Staci, and Lillian Mowry. Williams' Basic Nutrition and Diet Therapy. 15th ed. St. Louis, MO: Elsevier/Mosby, 2017.

PERIODICALS

Graudal, N. A., T. Hubeck-Graudal, and G. Jürgens. “Effects of Low-Sodium Diet vs. High-Sodium Diet on Blood Pressure, Renin, Aldosterone, Catecholamines, Cholesterol, and Triglyceride.” American Journal of Hypertension 25, no. 1 (2012): 1–15.

Harnack Lisa J., Mary E. Cogswell, James M. Shikany, et al. “Sources of Sodium in U.S. Adults from 3 Geographic Regions” Circulation 135, no. 19 (May 2017): 1775–83.

WEBSITES

American Heart Association. “Sodium and Your Health.” Heart.org . https://sodiumbreakup.heart.org/sodium_and_your_health (accessed May 23, 2018).

Cleveland Clinic. “Low-Sodium Diet Guidelines.” My.ClevelandClinic.org . https://my.clevelandclinic.org/health/articles/15426-sodium-controlled-diet (accessed May 23, 2018).

MedlinePlus. “Dietary Sodium.” U.S. National Library of Medicine, National Institutes of Health. https://medlineplus.gov/sodium.html (accessed May 23, 2018).

University of California San Francisco (UCSF) Medical Center. “Guidelines for a Low-Sodium Diet.” UCSFHealth.org . https://www.ucsfhealth.org/education/guidelines_for_a_low_sodium_diet/index.html (accessed May 23, 2018).

Zeratsky, Katherine. “Sodium: How to Tame Your Salt Habit.” Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/sodium/art-20045479 (accessed May 23, 2018).

ORGANIZATIONS

Academy of Nutrition and Dietetics, 120 S. Riverside Plaza, Ste. 2190, Chicago, IL, 60606-6995, (312) 899-0040, (800) 877-1600, amacmunn@eatright.org, http://www.eatright.org .

American Heart Association, 7272 Greenville Ave., Dallas, TX, 75231, (888) 242-8883, help@onlineaha.org, https://www.onlineaha.org .

British Heart Foundation, Greater London House, 180 Hampstead Rd., London, UK, NW1 7AW, +44 20 (0300) 330 3322, http://www.bhf.org.uk .

British Nutrition Foundation, New Derwent House, 69-73 Theobalds Rd., London, UK, WC1X 8TA, +44 20 7557-7930, postbox@nutrition.org.uk, http://www.nutrition.org.uk .

International Food Information Council Foundation, 1100 Connecticut Ave. NW, Ste. 430, Washington, DC, 20036, (202) 296-6540, info@foodinsight.org, http://www.foodinsight.org .

Tish Davidson, MA
Revised by Anne P. Nugent, PhD RNutr

  This information is not a tool for self-diagnosis or a substitute for professional care.