The Reagan administration has proposed rules that would require food manufacturers who use nutrition labels to list how much sodium is in their processed foods. It would also set conditions under which products can claim to be "low sodium," "reduced sodium" or "sodium-free."

Sodium is linked to high blood pressure, a problem for about 60 million Americans and a contributor to heart disease and strokes. The National Academy of Sciences says many Americans unknowingly consume more sodium than the safe daily amount of 1,100 to 3,300 milligrams. (A teaspoon of salt contains 2,000 milligrams of sodium.)

Under the proposed regulations, manufacturers who are now required to place nutrition labels on their foods--those who make nutrition claims or add nutrients to a product--would be required to include information on sodium. About 40 percent of foods have nutrition labels.

Arthur Hull Hayes Jr., commissioner of the Food and Drug Administration, said the proposed regs would "do much to help Americans reduce their salt and sodium intake." Last year, the FDA started a program to encourage manufacturers to provide sodium labeling voluntarily.

But Rep. Albert Gore Jr. (D-Tenn.) said that while the voluntary program and the proposed regs are a "step in the right direction," they fall "far short of providing adequate safeguards to consumers who must carefully watch their sodium intake." Gore and other congressmen have sponsored legislation that would require more extensive labeling.

The agency is also encouraging, but not requiring, manufacturers to disclose the potassium content of foods. People with kidney disease and other problems who must control sodium intake generally must limit their potassium intake as well. Those on low-sodium diets often use potassium in place of sodium.