Although chloride is a critical electrolyte, it often receives little dietary attention. This may be due to the fact that the majority of chloride in our diet is derived from salt. Chloride makes up approximately 40% of sodium chloride (table salt) and, under normal circumstances, deficiencies of this mineral are rare. Chloride is found in almost all foods, and consists of .15% of our overall body weight.
As with the other electrolytes, chloride is responsible for the control and maintenance of all fluids found within the body. It also plays integral roles in the regulation of the body’s acidity balance (PH), and assists us with certain muscle and nerve processes. Its most important function may be in its digestive actions.
Table salt (sodium chloride) is the major source of our dietary intake of chloride. Vegetables and various animal sources contain abundant amounts of chloride as well. Because of the high bioavailability of salt/sodium in all foods, a food graph is omitted.
Chloride is vital in the digestion process. In the stomach, it is an essential component of gastric juices, particularly hydrochloric acid. Hydrochloric acid, in conjunction with certain enzymes, aids in the digestion of amino acids. A particular example is the unavailable enzyme pepsinogen. Hydrochloric acid is necessary to turn the enzyme pepsinogen, into the digestible form, pepsin. Hydrochloric acid also helps protect our bodies by destroying pathogens that are ingested from foods. It also aids in the absorption of many nutrients and is critical in the prevention of fungal growth of the small intestine.
There are a variety of clinical studies associated with chloride intake. Because chloride is extremely important in fluid balance, it may be used with sodium to prevent dehydration of those persons involved in strenuous activities or exercise.  Certain illnesses may also cause chloride serum levels to drop. Chloride is often used in certain medications to regain fluid lost from various illnesses, such as diarrhea and vomiting. [2, 3]
Research has also shown that plasma volume levels (PV) of the blood may be directly associated with chloride intake, as well as the overall affect of fluid regulation in the body at certain altitudes. 
Chloride may also be of great physiological importance in the central nervous system. The amino acid glycine, and neurotransmitter GABA (Gamma-Aminobutyric Acid), are influenced by chloride and its associated negative ionic charge.
Like most minerals, there has not been a clearly defined RDA (recommended daily allowance) for chloride. Estimated minimum requirements and tolerable upper level intakes have, however, been established by a number of health agencies. The Food and Nutrition Board standards are listed as:
|0-6 months||180 mg/day|
|6-11 months||300 mg/day|
|Greater than 10 years of age||750 mg/day||750 mg/day||750 mg/day|
Chloride deficiencies may be directly influenced by fluid loss caused by severe burns, excess sweating, diarrhea, and prolonged vomiting. Deficiencies may occur, but as previously noted, are extremely rare. Chloride deficiencies are associated with the lowering of acidity levels (alkalosis), fluids, and potassium levels in the body. Low concentrations of chloride levels in the blood are defined as hypochloremia. This condition is usually linked with hyponatremia, or lowered sodium levels in body (i.e. skeletal, tissue) and blood system.
Hypochloremia without hypornatremia is usually found in those suffering from an underlying medical condition. These conditions include pyloric stenosis in infants, uncontrollable vomiting, chronic diarrhea, and Barter’s syndrome (or defective chloride reabsorption). [5, 6]
There exists a potential for chloride to increase overall blood pressure due to excessive sodium chloride intake.  This may result solely from excessive sodium intake. Water retention and hypertension (high blood pressure) are not found singularly in excessive chloride intake, but only when combined with sodium. (e.g. table salts and sea salts). Signs of chloride overdose include an “upset in acid-base balance.” 
1. Banister A, et al. Treatment of Hypernatraemic Dehydration in Infancy. Arch Dis Child. Mar 1975; 50(3): 179-86.
2. Holmberg C. Congenital Chloride Diarrhoea. Clin Gastroenterol. Jul 1986; 15(3): 583-602.
3. Majalanabis D, et al. Hypotonic Oral Rehydration Solution in Acute Diarrhoea: A Controlled Clinical Trial. Acta Paediatr. Mar 1995; 84(3): 289-93.
4. Greenleaf JE, et al. Sodium Chloride-citrate Beverages Attenuate Hypovolemia in Men Resting 12 h at 2800 m Altitude. Aviat Space Environ Med. Oct 1998; 69(10: 936-43.
5. Grossman, H., Duggan E., McCamman, S., Welchert, E. & Hellerstein, S. (1980) The dietary chloride deficiency syndrome. Pediatrics 66: 366-374.
6. Simopoulos, A. & Bartter, F.C. (1980) The metabolic consequences of chloride deficiency. Nutr. Rev. 38: 201-205.
7. Boegehold, M. & Kotchen, T.A. (1991) Importance of dietary chloride for salt sensitivity of blood pressure. Hypertension 17 (S1): 158-161.
8. Herbert, Victor. “Vitamins and Minerals Plus Antioxidant Supplements” Total Nutrition Ed. Victor Herbert, M.D., Genell J. Subak-Sharpe, M.S. New York: Saint Martin’s Griffin, 1995. 94-118.