Sodium: Too Much of a Good Thing The Dangers of Sodium Poisoning

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Our bodies are finely-tuned machines with lots of back-up systems in place. Sodium is one of many substances that our bodies need to function properly. Not surprisingly, our bodies have lots of back-up systems to keep the sodium levels in our blood exactly where they need to be.

Most of us know that too much salt in our diets is bad for people with high blood pressure. But most people don't realize that salt actually can be poisonous. Taking in a lot of sodium can overwhelm our back-up systems and cause dramatic increases in sodium levels. That's true if we take it all at once, or if we take in large amounts over a period of days or weeks.

This can mean eating ordinary table salt, rock salt, or high-sodium foods like soy sauce. In this case, a young man drank a lot of soy sauce on a dare. Long ago, salt was used to make people throw up after poisoning; this dangerous "treatment" has been fatal. In other cases, people with mental health problems have drunk soy sauce or eaten salt – or given salt to their children. A developmentally delayed man ate a lot of salt intended for a mouthwash. Infants were poisoned when salt was mistaken for sugar in formula. A woman with dementia ate salt from a salt shaker at her bedside. A child with cravings for non-food items (pica) ate rock salt. A shipwrecked man drank ocean water and suffered from salt poisoning.

Dehydration can cause high sodium levels, too; this can happen because of a lot of sweating (from high fever or high heat), a lot of vomiting, or a lot of diarrhea. There are some medical conditions which can cause sodium levels to get too high.

Too much sodium can cause dangerous, even fatal effects. When there's too much sodium in the bloodstream, water rushes out of our cells to dilute it. That's damaging to most cells; it's devastating to brain cells. As they shrink, they're torn away from their usual locations. Torn blood vessels and fluid build-up in the brain cause seizures and coma. Fluid can build up in the lungs, causing trouble breathing. Other symptoms include intense thirst, nausea, vomiting, and weakness. Kidney damage also occurs.

Most people won't eat too much salt or drink very salty liquid. It tastes bad and makes them very thirsty. That might not stop people who can't really tell what they’re doing, for example people with developmental delays or dementia. And, of course, it didn't stop the young man who drank soy sauce on a dare.

If you think someone has swallowed too much salt, give water if awake and breathing okay. Call 911 if the person won't wake up, is not breathing, or is having seizures. In any case, use the webPOISONCONTROL^® online tool for guidance or call Poison Control at 1-800-222-1222. The experts will tell you what to do right away.

Take Home Message:

• Sodium is essential to human health. But too much sodium is poisonous.
• Sodium is found in table salt, rock salt, pickling salt, and sea salt.
• Soy sauce contains high levels of sodium.
• Sodium poisoning can cause seizures, coma, and death.

Rose Ann Gould Soloway, RN, BSN, MSEd, DABAT emerita
Clinical Toxicologist