Sodium

Sodium is an essential mineral commonly referred to as salt. (Table salt is actually a combination of sodium and chloride.) It is involved in body water balance and acid-base balance and is the major extracellular (outside the cell, including blood and fluid) mineral. Sodium is present in small quantities in most natural foods and is found in high amounts in processed, canned, cooked, and fast foods. Although most people are capable of excreting excess sodium, some individuals are sodium sensitive because they lack this capacity. In these people, excess sodium retention causes edema (an excess accumulation of extracellular fluid) and contributes to high blood pressure. Sodium-sensitive individuals can limit intake by concentrating food choices on natural, whole foods and avoiding high-sodium (i.e., salty) commercially prepared foods. Food labels provide information about sodium content. The 2004 Institute of Medicine's recommendation for sodium intake is 1.5 grams per day,⁷⁵ while the tolerable upper limit (UL) is 2.3 grams of sodium per day.

One of the key ingredients in sports beverages is sodium because it helps drive the desire to drink and because it helps maintain blood volume. Maintenance of blood volume is a key factor in athletic performance; it is related to the ability to deliver nutrients to cells, to the removal of metabolic by-products from cells, and to the maintenance of the sweat rate.

Because of sweat losses, athletes are likely to require more than the 1.5 grams of sodium recommended for the general public. On hot and humid days when sweat losses of sodium are high, athletes may require more than 10 grams of sodium per day, a level that dramatically exceeds the UL of 2.3 grams per day. Therefore, the Institute of Medicine's recommendation for sodium intake is not applicable to most athletes and should not be followed. On the contrary, athletes should regularly consume salty foods and beverages when exercising or competing in hot and humid conditions. The higher athlete requirement for salt is recognized in the recommendations of the Institute of Medicine, which state that the general recommendation is not applicable to those who sweat regularly.⁷⁶