Deemed the "queen of electrolytes," chloride is the second most abundant electrolyte in the body. Through its function as an electrolyte, chloride affects many systems in the body, and apart from its electrolyte role, it also is essential for gastrointestinal functioning. This article will discuss chloride's role in the body, how to test for it, and how to ensure proper levels.

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What is Chloride?

Chloride is found naturally and mostly bound to sodium, forming sodium chloride or table salt. Sodium chloride is most commonly sourced from halite minerals and is also found on the bottom of the oceans. Chloride is essential for life.

Chloride carries a negative charge; the element chlorine is formed when this charge is removed. Chlorine is a toxic gas used as a chemical weapon during World War I. However, it is also used in the production of textiles and materials as well as a disinfectant.

What is Chloride's Role in The Body?

Chloride has two main functions in the body. First, chloride functions as an electrolyte. Second, chloride in the form of hydrochloric acid (HCL) is a digestive enzyme.

Electrolyte Function

Because chloride carries an electric charge, it is considered an electrolyte, along with sodium, potassium, magnesium, and calcium. Electrolytes produce ions and thus can affect fluid and nutrient movement into and out of the cell. Chloride plays a large role in the nervous system, affecting the growth and action of brain cells called neurons, neurotransmitter uptake, and more. Chloride also plays a role in the firing of muscle fibers. Chlorides' negative charge contributes to the body's pH levels or acid-base balance. Chloride channels, where the ions can flow through, are highly concentrated in the lungs, gastrointestinal system, and pancreas.

Digestive Enzyme Function

HCL is made from the parietal glands in the stomach lining and released in the gastric juices and other digestive enzymes. HCL has three main functions. First, its acidic nature kills any foreign bacteria. Second, it initiates the breakdown of proteins, readying them for further degradation. Third, it converts the enzyme pepsinogen to its active form, pepsin. HCL also has an antibacterial action. Gastrin, a hormone secreted by G-cells, is responsible for HCL release from the parietal cells.

Cystic fibrosis is a hereditary condition that occurs due to a genetic mutation in a protein that carries chloride ions out of the cell. People who have cystic fibrosis have poor digestion and absorption, which affects growth and development, salty skin, liver damage, infertility, and are at an increased risk of lung infections.

How to Test Chloride Levels

Chloride can be tested in the blood or urine. Blood chloride testing, such as the test by BostonHeart Diagnostics, has a range of 96 to 106 milliequivalents per liter (MEq/L). Chloride can also be found in Comprehensive Metabolic Panels (CMPs), such as the CMP by Access Medical Laboratories. Electrolyte panels will also give chloride levels.

Hyperchloremia

Elevated chloride blood levels are referred to as hyperchloremia. How hyperchloremia affects people depends on their health, nutritional status, and medication use. Symptoms of chronic hyperchloremia include high blood pressure, irregular heart rate, fluid retention, numbness and tingling, muscle spasms, twitches, weakness, confusion, difficulty concentrating, personality changes, convulsions, and seizures. Hyperchloremia can result from dehydration due to vomiting, diarrhea, excessive sweating, or insufficient fluid intake. It can also result from high sodium levels, diabetes insipidus, Addison's disease, and starvation.

It's important to note that various medications such as estrogen, cortisol, ammonia chloride, and non-steroidal anti-inflammatories (NSAIDs) such as Advil and Aleve may elevate chloride levels. Those undergoing chemotherapy are at a higher risk of hyperchloremia due to nausea, vomiting, and kidney problems that result from the treatment.

Hypochloremia

Low chloride blood levels can be due to vomiting and diarrhea, congestive heart failure, burns, Addison’s disease, metabolic alkalosis, chronic lung disease, and hyperaldosteronism.

Chloride may also be measured in the urine via a 24-hour collection like the test offered by Access Medical Laboratories. Urine chloride levels should be between 110 to 250 mEq per day.

Elevated urine levels of chloride can indicate adrenal problems, kidney inflammation, a high salt diet, low potassium levels, and polyuria (large amounts of urine production).

Decreased urine chloride levels indicate low salt intake, Cushing's syndrome, sodium retention, elevated antidiuretic hormone, and fluid loss.  

How to Make Sure You Are Getting Enough Chloride in Your Diet

The Academies of Science, Engineering, and Medicine created a Food and Nutrition Board that made Dietary Reference Intakes (DRI) for vitamins and minerals. One such DRI is the Recommended Daily Allowance (RDA), defined as the average daily intake needed to achieve nutritional adequacy in most people. However, when evidence is lacking to create an RDA for a vitamin or mineral, an Adequate Intake (AI) will be formed. AIs are levels assumed to achieve nutritional adequacy. Another DRI, Tolerable Upper Intake (UL), is the highest daily amount of a vitamin or mineral that would not cause an adverse effect. Chloride has AIs and ULs that are categorized by age and sex.

Chloride AI and UL

Pregnant and lactating women's values are categorized separately due to the often different nutritional requirements for women in these populations. However, for chloride, the AI and UL for pregnant and lactating women are the same as their respective age groups.

Chloride can be found in small amounts in meat and seafood, such as shrimp and seaweed. However, the main source of chloride in the diet is in the form of sodium chloride, or table salt, and foods high in table salt, such as processed foods like hot dogs, potato chips, and condiments like Worcestershire sauce, ketchup, and soy sauce. "Salt-free" foods often eliminate sodium while keeping chloride and thus may contribute to chloride consumption. Other sources of chloride include tomatoes, whole-grain foods, lettuce, rye, olives, and celery.

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Summary

Chloride is incredibly important for human health, significantly affecting the nervous, muscular, gastrointestinal, and pulmonary systems. Testing chloride levels can help to assess a person's health status, and ensuring proper levels is essential for proper functioning.