What Happens If You Don't Consume Enough Sodium

Spilled salt shaker on black countertop

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People concerned about getting too much sodium in their diets will often try to cut it out entirely, checking food labels and recipes for any sign of added salt (sodium chloride). While this may be a prudent thing to do, especially if you have high blood pressure, there may be risks if you consume too little sodium.

Sodium's Function in Your Body

As much as sodium has been demonized in the American diet—mostly because we consume far too much—it actually plays as vital a role in the functioning of our bodies. Sodium (like calcium, magnesium, phosphate, and potassium) is an electrolyte, meaning that it creates an electrically charged ion when dissolved in fluids like blood.

Our bodies need electrolytes to facilitate nerve impulses and regulate body functions such as heart rate, digestion, respiration, brain activity, and blood pressure. Sodium helps maintain the fluid balance in and around cells (including the volume of fluid in the blood) and helps regulate nerve and muscle function.

High sodium levels in your blood—above 145 milliequivalents per liter (mEq/L)—can affect fluid balance and contribute to high blood pressure. By contrast, low sodium levels (below 135 mEq/L) decrease blood pressure and interfere with the activity of nerve cells and the muscles of the heart and digestive tract.

Causes of Sodium Deficiency

While you lose a little sodium every day when you sweat or urinate, it is generally not enough to cause a sodium deficiency unless you are severely malnourished. By and large, the foods we eat provide us with more than enough sodium to replace what we lose.

However, it is possible to be sodium-deficient if you overexert yourself and lose excessive amounts of sodium in sweat. You can also drive your sodium levels down by drinking too much water and diluting the concentration of sodium in your body.

Both of these things can lead to a potentially dangerous condition known as hyponatremia. With hyponatremia, the extreme loss of sodium can trigger symptoms ranging from muscle cramps, nausea, vomiting, and dizziness to shock, coma, and death.

This is why athletes are routinely advised to consume electrolyte-rich sports drinks during strenuous activities to compensate for the loss of sodium and other essential minerals. However, athletes still need to be careful. If you drink too much (even sports drinks) during an endurance event, such as a marathon, you can quickly develop hyponatremia.

This is because our kidneys can eliminate between 5 and 7.5 gallons of water a day, but can't get rid of more than 27 to 34 ounces per hour. As a result, endurance athletes are advised to hydrate well before exercise, and then consume about 13.5 to 27 ounces per hour. However, this can vary from person to person, so it's best to calculate hydration needs by weighing yourself before and after exercise to determine sweat loss.

There are other conditions that can cause hyponatremia by either depleting fluid level or causing the excessive retention of fluids. This is especially true among older adults who take medications or have medical conditions that place them at risk. Risk factors include:

  • Chronic kidney disease
  • Cirrhosis
  • Congestive heart failure
  • Diuretics ("water pills") used to treat high blood pressure and edema (fluid overload)
  • Hypothyroidism (low thyroid function)
  • Lung cancer and secondary adrenal gland tumors
  • Remeron (mirtazapine), a tetracyclic antidepressant
  • Tegretol (carbamazepine), an anticonvulsant
  • Tricyclic antidepressants

Recommended Sodium Intake

According to the Office of Disease Prevention and Health Promotion (ODPHP), you need around 1,500 milligrams (mg) of sodium per day to replace whatever you lose in urine and sweat. In most cases, we consume enough in our regular diet and then some.

The ODPHP recommends that American adults consume less than 2,300 milligrams of sodium per day as part of a healthy dietary routine. Furthermore, African Americans, people with high blood pressure, and those over 50 are advised to limit their intake to 1,500 milligrams per day due to the increased risk of cardiovascular disease.

Consider how quickly the sodium levels add up if you eat just four ounces of beef (60mg), 1 cup of milk (140mg), 1 cup of greens (100mg), two eggs (350mg), an ounce of blue cheese (375mg), and 1 slice of refined white bread (175mg), and a cup of plain yogurt (150mg). Even without a grain of added salt, you're already more than halfway to your 1,500-milligram target.

Unfortunately, Americans tend to eat far more than this. In fact, according to ODPHP, the average American consumes around 3,400mg of sodium day. About 70% of daily intake comes from packaged and restaurant foods.

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