The Benefits and Drawbacks of Sodium

Salt helps the body regulate fluid levels as a vital part of the sodium–potassium pump in cells. This important cell function moves sodium and potassium ions in and out of cells, maintaining a fluid balance within. If there is not enough sodium present, this pump ceases to function, and the cell becomes hypertonic or filled with water. When a cell is hypertonic for too long, it dies.

Salt also helps maintain fluid levels through the urinary tract. Urine is a combination of sodium and water; when salt intake is low, urine output decreases. Low urine output can cause problems with the bladder or kidneys.

Sweat is composed of water and essential minerals such as sodium and potassium. During exercise, the body sweats and flushes out both water and salt, which leads to dehydration if not replenished. If a person sweats heavily, the body is unable to keep up with the sodium loss, which leads to muscle twitching and cramps.

High-sodium sports drinks are specifically designed to replace these lost minerals and may help speed up recovery from muscle cramping. However, they're not usually necessary unless a person is extremely physically active.

Sodium also plays an important role in regulating brain function. Sodium facilitates nerve impulses and communication in the brain, and a low sodium level slows down these communications. As mentioned above, sodium plays a key role in fluid regulation, and the brain relies on its surrounding fluid to function optimally.

Low sodium levels can lead to brain fog, mental fatigue, and headaches. Severe sodium deficiency can lead to brain swelling, such as cerebral edema.  

Salt walks a thin line when it comes to regulating blood pressure in the body. Often the scapegoat for high blood pressure, sodium is actually essential in maintaining healthy numbers. Salt consumption increases the amount of fluid in the body and directly impacts blood volume.

People who avoid salt altogether will experience a low blood volume, which leads to low blood pressure. Experts recommend that adults consume less than 2,300 milligrams (mg) of sodium each day for optimal blood pressure levels, but remember the minimum is about 500 mg.

Sodium plays an important role in nerve signaling. Nerves send electrical impulses throughout the body that control muscle movement, sensations, and involuntary functioning. When nerves need to communicate, special channels open and allow sodium in, which signals the nerve to send its message.

The message moves from nerve to nerve by this rush of sodium until it reaches the brain. Low sodium levels make this process sluggish and ineffective, especially in people with diabetes.

While sodium plays a crucial role in optimal health, too much can cause serious problems. A high-sodium diet affects proteins responsible for heart contractions, which can lead to abnormal rhythms or even heart failure. Too much sodium also increases blood pressure levels, which increases the risk of stroke or cardiovascular disease.

Kidney stones are hard deposits of minerals and salts that form in concentrated urine. Concentrated urine occurs when the diet includes an overabundance of either salt or sugar. Sodium and calcium share the same kidney transport, so too much sodium causes the kidneys to excrete extra calcium as well, contributing to hard kidney stones.

Drinking extra water and decreasing sodium intake can help the stones pass quickly with less pain.

An overabundance of sodium can cause headaches and brain fog in some people. Too much sodium often leads to dehydration, which is a major cause of localized headaches. One study found that people with lower-sodium diets had one-third fewer headache days than those with high-sodium diets.

However, some scientists suggest that headaches are more likely attributed to high blood pressure associated with the overconsumption of sodium rather than the salt itself.

While sodium regulates fluid levels in the body, too much salt can cause the body to retain extra water. An overabundance of sodium causes cells to swell with water, and sometimes this extra liquid leaks into the surrounding tissue. This tissue then becomes inflamed and swollen, triggering edema. One study found that high-sodium diets greatly increase the occurrence of leg edema, and elderly men were the most affected group.

An abundance of research shows that an excessive intake of sodium is a direct cause of high blood pressure. One study suggests that a small reduction of 1.75g of sodium per day can lead to a staggering 4.2 systolic/2.1 diastolic mmHg reduction in blood pressure.

Similar studies found that a modest decrease in sodium consumption led to not only lower blood pressure levels but also to a decreased risk of death from cardiovascular disease.