Salt, also known as sodium chloride, is 40 percent sodium by weight and the number-one source of that element in our diets. We need only 1,500 mg of sodium per day - far less than the average intake of five to six grams per day!
Sodium plays a critical role in our bodies by helping regulate water balance and controlling muscle and nerve function. Sodium deficiency is rare. Only those who engage in vigorous exercise in hot environments need be concerned about taking in extra sodium to compensate for the amount lost through perspiration. Most of us should think instead about how to reduce the sodium in our diets.
Some people are clearly "salt-sensitive": excess dietary sodium causes them to retain fluid and, as a result, have increased circulatory volume (putting excess strain on the heart and kidneys) and blood pressure. People who are not salt-sensitive seem to be able to handle a high amount of dietary sodium without any difficulty. Although some people with high blood pressure, heart, or kidney disease do better on a sodium-restricted diet, I find the evidence of salt being the cause of these conditions unclear. Still, I think it's a good idea to cut down, especially if you have a family history of these conditions.
Sodium content is high in processed foods as it acts as a flavor enhancer and preservative. So start by eliminating or significantly reducing your intake of processed meals, canned soups and snack foods.
Keep the saltshaker off the table, and exclude foods with visible salt like pretzels, chips and salted nuts. You can reduce some of the sodium in pickled foods by rinsing or soaking them in fresh water before eating them. Over time, you will notice that your taste for sodium will change and foods you once found appetizing will seem too salty.
I also recommend increasing your potassium intake because these two elements balance each other. It is the ratio of sodium to potassium in the diet and in our systems that seems to affect blood pressure and kidney function more than salt levels alone. Most fruits are good sources of potassium, especially bananas, as are dark leafy greens, potatoes and legumes. Salt substitutes contain potassium chloride; do not use them without first consulting with your physician. And never take potassium supplements, except as prescribed by a physician.
Andrew Weil, M.D.