Sodium occurs naturally in most foods. The most common form of sodium is sodium chloride, which is table salt. Milk, beets, and celery also naturally contain sodium, as does drinking water, although the amount varies depending on the source.

Sodium is also added to various food products. Some of these added forms are monosodium glutamate, sodium nitrite, sodium saccharin, baking soda (sodium bicarbonate), and sodium benzoate. These are ingredients in condiments and seasonings such as Worcestershire sauce, soy sauce, onion salt, garlic salt, and bouillon cubes.

Processed meats, such as bacon, sausage, and ham, and canned soups and vegetables are all examples of foods that contain added sodium. Fast foods are generally very high in sodium.

For individuals who are sodium-sensitive, an increased intake of sodium may contribute to high blood pressure. Therefore, people with high blood pressure may be advised to reduce sodium intake; all patients with high blood pressure should discuss this issue with their doctor. Reducing sodium can also reduce the side effects from certain prescription medications.

In addition, sodium may lead to fluid retention in patients with congestive heart failure, cirrhosis, or kidney disease. These patients should be on strict sodium-restricted diets as prescribed by their doctor.

Dietary sodium is measured in milligrams (mg). Table salt is 40% sodium; one teaspoon of table salt contains 2,300 mg of sodium.

The National Research Council of the National Academy of Sciences recommends an approximate daily range of 1,100 to 3,300 mg of sodium for adults. For people with high blood pressure, hypertension experts are recommending no more than 2,300 mg of sodium a day. The average sodium intake in the United States is between 4,000 and 5,000 mg per day.

Patients with congestive heart failure, liver cirrhosis, and kidney disease may need to be on low-sodium diets as prescribed by their doctor.

Specific recommendations regarding sodium intake do not exist for infants, children, and adolescents. Eating habits and attitudes about food formed during childhood are likely to influence eating habits for life, and for this reason, moderate intake of sodium is suggested.