What does sodium chloride do for a person?

October 2, 2025 •

4 min read

Sodium chloride, or common table salt, is an essential compound that plays a vital role in numerous bodily functions. While often viewed with caution due to high intake concerns, a proper balance of this electrolyte is critical for nerve impulses, muscle function, and maintaining proper hydration.

Quick Summary

Sodium chloride is a fundamental nutrient that, when dissolved in the body, functions as an electrolyte essential for regulating fluid balance, conducting nerve impulses, and facilitating muscle contraction. Both its sodium and chloride components are necessary for maintaining normal physiological functions, though excessive intake can lead to serious health issues.

Key Points

Electrolyte Function: Sodium chloride separates into electrolytes ($Na^+$ and $Cl^-$) in body fluids, which are crucial for conducting electrical signals necessary for nerve and muscle function.
Fluid Balance Regulation: The primary function of sodium is to help regulate the body's fluid balance by controlling the amount of water retained or excreted by the kidneys.
Blood Pressure Control: By influencing blood volume, sodium directly impacts blood pressure; excessive intake is a major contributor to hypertension.
Digestion Support: Chloride is a necessary component of hydrochloric acid in the stomach, which is vital for proper digestion and nutrient absorption.
Health Risks of Excess: Too much sodium chloride can lead to serious health issues, including high blood pressure, heart disease, kidney damage, and osteoporosis.
Risks of Deficiency: Low sodium levels can cause fatigue, muscle cramps, and neurological problems, though this is less common from diet alone.
Medical Uses: Saline, a sodium chloride solution, is used in IV therapy, wound cleaning, nasal irrigation, and eye drops for various medical purposes.

The role of sodium chloride as an electrolyte

Sodium chloride (NaCl) is composed of two essential minerals: sodium and chloride. In the body's fluids, this compound separates into its ionic forms, $Na^+$ and $Cl^-$, which are known as electrolytes. These electrically charged particles are fundamental to the normal functioning of every cell and organ. The balance of these electrolytes, especially sodium, is tightly regulated by a complex system involving the kidneys, brain, and adrenal glands. This system ensures that the body retains or excretes the right amount of sodium and water to maintain homeostasis.

Maintaining fluid and blood pressure balance

One of the most critical functions of sodium chloride is regulating the body's fluid balance. Sodium is the primary electrolyte responsible for determining the amount of fluid outside of the body's cells, known as extracellular fluid. When sodium levels increase in the bloodstream, it draws more water into the blood, which raises blood volume and, subsequently, blood pressure. Conversely, when sodium levels are low, the kidneys release excess water, helping to decrease blood volume and blood pressure. This mechanism is a key part of how the body regulates blood pressure, with excess sodium consumption being a primary contributor to hypertension.

Facilitating nerve impulses and muscle function

The balance of sodium and potassium across cell membranes is what creates an electrical charge, or membrane potential, essential for nerve function. Sodium plays a critical role in generating these nerve impulses. When a nerve cell is stimulated, sodium rushes into the cell, creating a nerve signal that is then transmitted to the brain and other parts of the body. This same process is crucial for muscle function, including the contraction and relaxation of both voluntary muscles and the involuntary cardiac muscle.

Aiding digestion with chloride

Chloride, the other component of sodium chloride, is just as important. It is a key ingredient in the production of hydrochloric acid ($HCl$) in the stomach. This stomach acid is necessary for proper digestion, helping to break down food and activate digestive enzymes. In addition, chloride works alongside sodium to help transport nutrients like glucose and amino acids across cell membranes.

Health implications of imbalanced levels

Maintaining the right balance of sodium chloride is crucial for health. Both deficiency and excess can lead to serious complications. For most people in modern societies, the primary concern is consuming too much sodium chloride, often from processed and packaged foods.

Dangers of high sodium intake (Hypernatremia)

Excessively high levels of sodium in the blood, a condition known as hypernatremia, can occur due to high intake combined with insufficient fluid. Chronic overconsumption of sodium is a major risk factor for several health issues:

High Blood Pressure (Hypertension): Leads to increased risk of heart disease, stroke, and kidney damage.
Cardiovascular Disease: The extra strain on the heart and blood vessels can lead to conditions like heart failure.
Kidney Issues: The kidneys work hard to excrete excess sodium, and high intake can damage these vital organs over time.
Osteoporosis: High sodium intake can increase calcium excretion, potentially weakening bones.
Stomach Cancer: Some studies suggest a link between high salt diets and an increased risk of stomach cancer.

Consequences of low sodium intake (Hyponatremia)

While less common from dietary restriction alone, low sodium levels (hyponatremia) can also be dangerous, particularly for athletes or those with certain medical conditions.

Fatigue and Weakness: The body's inability to maintain proper electrical signals can lead to low energy and muscle cramps.
Neurological Symptoms: Severe hyponatremia can cause headaches, confusion, seizures, and even coma due to brain swelling.
Gait Instability: Chronic mild hyponatremia has been linked to attention deficits and an increased risk of falls.

Dietary considerations for sodium intake

For most people, the challenge is reducing high sodium intake, not getting enough. A balanced diet of whole foods is the best approach for maintaining healthy sodium levels.


Comparison of Sodium Sources	Source	Sodium Content Contribution	Health Implications
Processed & Packaged Foods	Largest source, often hidden in items that don't taste salty (breads, cereals, sauces).	Primary driver of excessive intake, linked to hypertension and other chronic diseases.
Restaurant & Take-out Food	Major source, as many dishes are pre-seasoned with high levels of salt.	Contributes significantly to daily sodium, making it hard to control intake when eating out.
Home-cooked Meals	Controlled source; adding table salt while cooking accounts for a smaller portion of total intake.	Allows for precise control over sodium levels and substitution with other flavorings.
Natural Whole Foods	Low in sodium (fruits, vegetables), some contain natural sodium (milk, meat).	Best foundation for a healthy diet, naturally providing necessary sodium without excess.

Medical applications of sodium chloride

In addition to its dietary importance, sodium chloride has several vital medical uses, most commonly in the form of saline solution.

Intravenous (IV) Therapy: A sterile 0.9% sodium chloride solution (normal saline) is used to treat dehydration and electrolyte imbalances, particularly in cases of gastroenteritis or diabetic ketoacidosis.
Wound Care: Saline is the standard for cleaning and flushing wounds, as it is safe and does not cause irritation.
Nasal Irrigation: Nasal sprays or rinses containing saline help relieve congestion by moistening nasal passages and clearing mucus.
Eye Drops: Sodium chloride eye drops are used to treat dryness and swelling of the cornea.

Conclusion

In summary, what does sodium chloride do for a person? It provides the body with essential electrolytes—sodium and chloride—that are critical for regulating fluid balance, conducting nerve impulses, and facilitating muscle function. While a minimum amount is necessary for survival, the average diet often provides far more than needed, increasing the risk of serious health conditions like high blood pressure and heart disease. The key to good health is achieving and maintaining the right balance through mindful dietary choices, focusing on whole foods, and consulting with healthcare professionals for personalized advice regarding sodium intake. A balanced approach is necessary to reap the benefits of this essential nutrient while avoiding its potential pitfalls. For more on dietary guidelines, a great resource is the American Heart Association website.

Frequently Asked Questions

Sodium ($Na$) is a mineral and one of the chemical elements found in salt. Sodium chloride ($NaCl$) is the chemical compound known as table salt, which is composed of 40% sodium and 60% chloride. Nutritionally, most of our sodium intake comes from sodium chloride.

The recommended intake for sodium is generally less than 2,300 mg per day for adults, which is equivalent to about one teaspoon of salt. Some individuals, like those with high blood pressure, may need to consume even less.

Yes, excessive sodium chloride intake is a major health concern. It can lead to increased blood pressure, heart disease, kidney problems, and other complications due to fluid retention and strain on the body's systems.

Symptoms of low sodium, known as hyponatremia, can include nausea, headaches, confusion, fatigue, muscle weakness, and cramps. In severe cases, it can lead to seizures and coma.

Yes, medically, sodium chloride is used in several forms. Saline solution, which is a mix of salt and water, is used for intravenous drips to treat dehydration, for flushing wounds, and in eye and nasal drops.

To maintain healthy sodium levels, focus on eating fresh foods and limiting processed and packaged goods. Flavor your meals with herbs, spices, and citrus instead of relying heavily on salt. Getting enough potassium through fruits and vegetables can also help balance sodium's effects on blood pressure.

While different salts like table salt, sea salt, and kosher salt have minor differences in processing and trace mineral content, they all contain roughly 40% sodium by weight. From a nutritional standpoint, the differences are minimal.