Sodium (Na), Chloride (Cl)
Description
Sodium and chloride (found in table salt) are essential minerals.
A modest amount of salt is required for survival; the health implications of excess salt intake are controversial.
Sodium and chloride levels are tightly controlled in blood. Most sodium and chloride in the diet comes from table salt. Most nutritional focus is on sodium. What concerns chloride
generally concerns sodium.
In the general population, the focus is on decreasing intake. In
aerobic endurance athletes, the occasional focus is on increasing intake.
The total body sodium content of an adult is about 90 grams.
About 30% is found in bone.
Requirements: Adequate Intake (AI)
The 2004 US Food and Nutrition Board (FNB) adult daily
adequate intake levels for sodium
chloride (salt), sodium, and hence
chloride, are 3.8 grams, 1.5 grams, and 2.3 grams respectively.
These are based on the amounts needed to replace losses through
sweat in moderately active people and to achieve a diet that provides sufficient amounts of other essential nutrients.
The USDA value for sodium, used for nutritional supplement
and food labeling, is 2.4 grams.
The USDA value for chloride, used for nutritional supplement
and food labeling, is 3.4 grams.
A typical multivitamin/multimineral
contains 72 milligrams (2%).
Typical Intake (Sodium Chloride)
The average US daily dietary intake is at least 9 grams for men
and 6 grams for women.
Average dietary intakes of most people in the US are
significantly higher than recommended.
Tolerable Upper Intake Level (UL)
The FNB adult daily tolerable upper
intake level is 5.8 grams of
salt (2.3 grams of sodium).
It is based on the adverse effects of high sodium intakes on blood
pressure, a major risk factor for cardiovascular and kidney diseases.
The UL may be lower for those who are most sensitive to the
blood pressure effects of sodium: African Americans, the elderly, and those with hypertension, diabetes, or chronic kidney disease.
Sources Food
Most dietary sodium and chloride come from salt. By weight,
about 40% of salt is sodium, 60% chloride.
Most salt intake in the US is from salt added during food
processing or manufacturing, rather than from salt added at the table or during cooking.
Restaurant foods tend to be high in sodium. The lowest salt intakes are associ
ated with diets that emphasize
unprocessed foods, especially fruits, vegetables, and legumes.
The sodium and energy (caloric) content of selected foods is
listed in
Table 32
.
Nutrition for Sports, Essentials of 162
