Sodium and sodium chloride -- known commonly as salt -- occur naturally in foods, usually in small amounts. Salt and other sodium-containing ingredients are often used in food processing. Some people add salt and salty sauces, such as soy sauce, to their food at the table, but most dietary sodium or salt comes from foods to which salt has already been added during processing or preparation. Although many people add salt to enhance the taste of foods, their preference may weaken with eating less salt.
In the body, sodium plays an essential role in regulation of fluids and blood pressure. Many studies in diverse populations have shown that a high sodium intake is associated with higher blood pressure. Most evidence suggests that many people at risk for high blood pressure reduce their chances of developing this condition by consuming less salt or sodium. Some questions remain, partly because other factors may interact with sodium to affect blood pressure.
Following other guidelines in the Dietary Guidelines for Americans may also help prevent high blood pressure. An important example is the guideline on weight and physical activity. The role of body weight in blood pressure control is well documented. Blood pressure increases with weight and decreases when weight is reduced. The guideline to consume a diet with plenty of fruits and vegetables is relevant because fruits and vegetables are naturally lower in sodium and fat and may help with weight reduction and control. Consuming more fruits and vegetables also increases potassium intakes which may help to reduce blood pressure (box 14). Increased physical activity helps lower blood pressure and control weight. Alcohol consumption has also been associated with high blood pressure. Another reason to reduce salt intake is the fact that high salt intakes may increase the amount of calcium excreted in the urine and, therefore, increase the body's need for calcium.
Sodium has an important role in the body. However, most Americans consume more sodium than is needed. The Nutrition Facts Label lists a Daily Value of 2,400 mg per day for sodium [2,400 mg sodium per day is contained in 6 grams of sodium chloride (salt)]. In household measures, one level teaspoon of salt provides about 2,300 milligrams of sodium. Most people consume more than this amount.
There is no way at present to tell who might develop high blood pressure from eating too much sodium. However, consuming less salt or sodium is not harmful and can be recommended for the healthy normal adult (box 15).
Fresh fruits and vegetables have very little sodium. The food groups in the Food Guide Pyramid include some foods that are high in sodium and other foods that have very little sodium, or can be prepared in ways that add flavor without adding salt. Read the Nutrition Facts Label to compare and help identify foods lower in sodium within each group. Use herbs and spices to flavor food. Try to choose forms of foods that you frequently consume that are lower in sodium and salt.