Sodium 101: Lab Tests, Disorders, & How Much To Consume Daily

Sodium is an essential mineral for human health and was once one of the most valued commodities; in fact, the word "salary" comes from the Latin word for "salt" since salt was once used as a currency. While sodium is a critical mineral for our bodies to function properly, studies show that 90% of us are getting too much sodium. This article will discuss sodium's role in the body, how to test for it, and how to ensure enough in the diet.

[signup]

What is Sodium?

Sodium is the sixth most common element found in nature. It is technically a metal, although due to its high reactivity with other elements, it's never found as a metal in nature. Sodium makes up 2.6% of the earth's crust. The most common form of sodium is sodium chloride, commonly known as table salt.

What is Sodium's Role in The Body?

We have about 250 grams of sodium in our bodies, the equivalent of 3 or 4 saltshakers. Sodium is found in three areas of the body: the skeleton, the extracellular fluid, and the intracellular fluid. Sodium is an electrolyte and thus influences fluid balance, which can then affect nerve and muscle function. The kidneys are the primary regulator of sodium levels in the body. If sodium levels drop, the kidneys hold onto sodium and keep it in circulation. If sodium levels are increased, the kidneys release sodium in the urine.

However, when sodium levels are high enough that the kidneys cannot excrete enough to lower levels, sodium will build up in the blood, causing water to pool into the bloodstream. This results in an increased blood volume and puts more work on the body's blood pump, the heart, and also increases pressure in the blood vessels that deliver oxygenated and nutrient-rich blood, the arteries, which may contribute to high blood pressure. Chronically high blood pressure may increase the risk of kidney disease, heart disease, and stroke.

What is Hyponatremia?

Low levels of sodium, referred to as hyponatremia, can cause the following symptoms:

• Fatigue
• Weakness
• Confusion
• Muscle twitches
• Seizures

Due to sodium in the diet, hyponatremia is rare but may be seen in the following conditions:

• Adrenal insufficiency
• Sodium-losing kidney disease
• Severe burns
• Chronic diarrhea
• Continuous vomiting
• Extreme sweating for long periods of time
• Diabetic ketoacidosis
• Overconsumption of diuretic medications
• Continuous gastric suction (stomach pumping)

What is Hypernatremia?

High levels of sodium, referred to as hypernatremia, can cause the following symptoms:

• Confusion
• Muscle twitches
• Vomiting
• Diarrhea
• Increase thirst
• Low urine output
• Seizures

Hypernatremia can be seen in the following conditions:

• Dehydration
• Overconsumption of diuretic medications
• Adrenal disorders
• Kidney diseases
• Diabetes insipidus

How to Test Sodium Levels

Sodium levels can be tested as a single marker in a serum test or are parts of blood panels, including comprehensive metabolic panels (CMP), basic metabolic panels (BMP), and electrolyte panels. The standard reference range for sodium in the blood is 135 to 145 milliequivalents per liter (mEq/L), although levels may vary slightly from lab to lab.

CMPs, such as the CMP panel by Access Medical Laboratories, give electrolyte levels, including sodium, as well as markers of kidney and liver function, blood sugar, calcium and protein levels, and a marker of fluid balance. CMPs are often done during a regular checkup or if kidney or liver disease is suspected.

BMPs, such as the BMP by BostonHeart Diagnostics, include the same markers as a CMP, except for protein and liver enzymes. Like CMPs, BMPs may be done as part of a regular checkup, when in the emergency room, or if monitoring for certain health conditions.

Electrolyte panels, such as the Electrolyte Panel by Access Medical Laboratories, will give sodium levels as well as the electrolytes chloride and potassium. Additionally, these panels also show carbon dioxide (CO2) levels, as fluctuations in CO2 will cause fluctuations in electrolyte levels. Electrolytes are often checked via CMPs or BMPs, but electrolyte panels may be done by themselves to check for fluid or acid and base imbalances.

[signup]

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

The Adequate Intake (AI) for sodium, created by looking at the lowest amount of sodium intake to prevent deficiency but also allowing for intake from nutritious foods, is set at 1,500mg per day. The current recommended limit, known as the Chronic Disease Risk Reduction Intake, for sodium intake is 2,300mg, and yet studies show that the average American takes in around 3,400mg of sodium daily. Over 70% of dietary sodium is from processed foods. An estimated 40% of sodium intake comes from deli meat sandwiches, pizza, soups, pasta mixed dishes, burritos and tacos, poultry, burgers, egg dishes including omelets, and savory snacks such as chips, popcorn, and crackers.

Various types of salt have varying levels of sodium. Iodized table salt contains the most sodium of any available salt, with 2,300mg of sodium per 1 teaspoon (tsp). Himalayan salt contains 2,200mg, and fine sea salt has 2,120mg per tsp. Coarse Kosher salt has 1,920mg per tsp. Hidden sources of sodium can be in the form of the food additives monosodium glutamate (MSG), sodium bicarbonate, sodium nitrate, and sodium benzoate. The current recommendation is to avoid foods with more than 200mg of sodium per serving, as those servings can add up quickly and exceed the 2,300mg daily sodium limit.

When looking to lower sodium levels, food labels can be both helpful and misleading. Here are six sodium food labels and their meanings:

In order to lower sodium, eating at home may be helpful as restaurant foods tend to have high sodium content. Additionally, reducing the intake of processed foods while increasing the amount of fresh fruits and vegetables, foods that are naturally lower in salt, can be a good idea. Replacing salt with fresh herbs and other spices helps keep foods flavorful and enjoyable. Keeping an eye on condiment intake can also help to manage sodium levels.

[signup]

Summary

Sodium is an essential nutrient as it plays a vital role in fluid balance and nerve and muscular contraction. Too little sodium can negatively impact the body, but it is relatively rare. Too much sodium is more common, as popular foods are filled with sodium. As sodium can impact our body, checking sodium levels to ensure there is no elevation or depression is important for health.