Sodium occurs naturally in most foods. For example, milk, beets, and celery have sodium. It is also present in drinking water, although the amount varies depending on the source of the drinking water.

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. They may be more familiar as ingredients 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.

Dietary sodium is measured in milligrams (mg). The most common form of sodium used is table salt, which is 40% sodium. One teaspoon of table salt contains 2,300 milligrams of sodium.

The National Research Council of the National Academy of Sciences recommends an approximate daily range of 1,100 to 3,300 milligrams of sodium for adults. The American Heart Association recommends that for every 1,000 Calories of food consumed, the sodium intake should be 1,000 milligrams and should not exceed the 3,000 milligram limit. The average intake in the United States is between 4,000 and 5,000 milligrams of sodium per day.

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.