A low sodium diet is a diet that is low in salt, usually allowing less than 1 teaspoon per day. Many diseases, including kidney disease, heart disease, and diabetes, require a patient to follow a low sodium diet.
There is no single origin for the idea behind low sodium diets. 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.
The Role of Sodium
The majority of sodium consumed comes from sodium chloride (NaCl), better known as salt. Salt has many useful properties, both in food preservation and for the body. 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,
Electrolyte —ions in the body that participate in metabolic reactions. The major human electrolytes are sodium (Na+), potassium (K+), calcium (Ca 2+), magnesium (Mg2+), chloride (Cl−), phosphate (HPO4 2−), bicarbonate (HCO3−), and sulfate (SO4 2−).
Hyponatremia —An abnormally low concentration of sodium in the blood.
Mineral —An inorganic substance found in the earth that is necessary in small quantities for the body to maintain a health. Examples: zinc, copper, iron.
salting was one of the few methods available for preserving foods, such as meat, through the winter. Salt also dissolves into the electrolytes Na+ and Cl1 that help maintain the right balance of fluids in the body, transmit signals through the nervous system, and cause muscles to contract and relax.
The kidneys are responsible for regulating the amount of sodium in the body. When the body has too much sodium, the kidneys filter some out and the excess amounts are excreted from the body in the urine. When the body does not have enough sodium, the kidneys help to conserve sodium and return the needed amount into the bloodstream. When a person eats too much salt, however, and the kidneys are not able to filter enough out, sodium begins to build up in the blood. In the same way that salt pulls water out of foods, sodium in the blood pulls out and holds water from cells in the body. This increases the volume of the blood and puts strain on the heart and circulatory system.
Ways to Reduce Salt Intake
According to a study done by the Mayo Clinic, the average American gets only 6% of their total salt intake from salt that is added at the table. Only 5% comes from salt that is added during cooking, and natural sources in food makeup only another 11 percent. The remaining 77% comes from processed or prepared foods. Many packaged meats, as well as canned and frozen foods, contain a surprising amount of salt. Salt is used so 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 aftertaste.
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 also have a much higher salt content than the same vegetable found in the fresh produce section. Frozen prepared meals should be avoided for the same reason, and canned soups usually contain much more salt than soups made a home. By reading the Nutrition Facts label on the side of commercially manufactured foods, dieters can determine how much sodium is in the food they are considering.
When choosing canned or frozen foods, dieters who wish to reduce their salt intake can often find a ‘low sodium’ option. The 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’ need only contain 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. To this they often add salt because it is an inexpensive way to improve the taste. Recently, some chain restaurants have begun providing dietary information about their meals. Usually this is printed in a pamphlet that is separate from the menu, so customers may need to ask for it. Some restaurant chains even provide this information on their websites so that customers can decide on a low-sodium meal before they visit 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.
Another time that salt can be eliminated from 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 an herb or spice mixture, it is important that the dieter 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. There are also artificial salt substitutes available, although kidney patients should avoid these as they are usually high in potassium, another mineral that is regulated by the kidneys.
The most obvious way to reduce salt intake is to cut back on the amount of salt added at the table. Since salt is an acquired taste, many doctors recommend simply removing the salt shaker from the table altogether. Most condiments like ketchup, mustard, and pickle relish are also high in salt. Eliminating these can also be a significant help. Many commercially available sauces, dips, and salad dressings also contain a lot of salt. By checking the labels on these condiments before purchasing, consumers can often find options with less sodium.
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 1500 to 2400 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.
- 1 large cheeseburger: 1,220 mg
- 1 cup canned soup: 800 mg
- 1 hot dog: 650 mg
- 12-ounce can of soda: 25 mg
- 1/2 cup cottage cheese: 425 mg
- 1 Tablespoon soy sauce: 800 mg
- 1 bean burrito: 920 mg
- 1 Saltine cracker: 70 mg
- 1 frozen enchilada: 680 mg
The low sodium diet is designed to lower the amount of sodium that a person consumes. While 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.
There are benefits of a low sodium diet 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 who have a family history of heart problems, people of African decent, 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 increase 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 in order to slow the progress of current conditions and prevent future problems. For kidney patients, a low sodium diet is necessary to prevent fluid retention.
Anyone thinking of significantly altering their regular diet should talk to their physician. 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.
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 3000 and 5000 milligrams of sodium per day, and a low sodium diet reduces this to a healthier level of between 1500 and 2400 milligrams per day. Since the physiological requirement for sodium for adults is only 500 milligrams daily, there is little danger that a person following a low sodium diet 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.
QUESTIONS TO ASK THE DOCTOR
- What kinds of foods should I avoid?
- How much sodium is best for me?
- Which foods are low in sodium?
- How will I know if I am consuming too little sodium?
- Are there any sign or symptoms that might indicate a problem while on this diet?
Low sodium diets are generally accepted as part of many programs that are aimed at lowering the serious risks posed by certain diseases, such as kidney and heart disease. Most health professionals agree that a low sodium diet is not only necessary for patients suffering from these diseases, but would also be healthy and beneficial for most Americans. There is a great deal of scientific research that supports a direct link between salt intake and blood pressure.
American Heart Association American Heart Association Low-Salt Cookbook. New York: Clarkson Potter, 2006.
Gazzaniga, Donald A. and Maureen A. Gazzaniga. The No-Salt, Lowest Sodium Light Meals Book. New York: Thomas Dunne Books, 2005.
James, Shelly V, The Complete Idiot’s Guide to Low-Sodium Meals. Indianapolis, IN : Alpha Books, 2006.
Shannon, Joyce Brennfleck ed. Diet and Nutrition Source-book. Detroit, MI: Omnigraphics, 2006.
Willis, Alicia P. ed. Diet Therapy Research Trends New York: Nova Science, 2007.
American Dietetic Association.120 South Riverside Plaza, Suite 2000, Chicago, Illinois 60606-6995. Telephone: (800) 877-1600. Website: <http://www.eatright.org>.
American Heart Association. 7272 Greenville Avenue, Dallas, TX 75231. Telephone: (800) 242-8721. Website: <http://www.americanheart.org>.
International Food Information Council. 1100 Connecticut Avenue, NW Suite 430, Washington, DC 20036. Telephone: 02-296-6540. Fax: 202-296-6547. Website: <http://ific.org>.
American Heart Association. ‘Sodium.’ undated, accessed April 27, 2007, <http://www.americanheart.org/presenter.jhtml?identifier=4708>.
Mayo Clinic Staff. ‘Sodium: Are You getting Too Much?’ MayoClinic.com, May 24, 2006. <http://www.mayo-clinic.com/health/sodium/NU00284>.
Mayo Clinic Staff. ‘Low-Sodium Diet: Why is processed food so salty?’ Mayo Clinic.com, 2006. <http://www.mayoclinic.com/health/food-and-nutrition/AN00350>.
Medline Plus. ‘Dietary Sodium.’ U. S. National Library of Medicine, April 23, 2007. <http://www.nlm.nih/gov/medlineplus/dietarysodium.html>.
Tish Davidson, M.A.