From lung cancer to pancreatic cancer, low sodium levels are a common sign of developing cancer. Along with identifying low sodium, cancer symptoms, and medical screening, oncologists are increasingly using sodium levels as a cancer red flag. 

Does Sodium Cause Cancer? 

High sodium intake has been linked to an increased risk of stomach cancer and a potential risk to other types of digestive cancers. Sodium is a proven contributor to other lifestyle diseases, including diabetes, obesity, and hypertension. These diseases may increase the risk of a cancer diagnosis as well. Variations of sodium are common food ingredients, making it difficult to meet the Centers for Disease Control and Prevention’s recommended limit of 2,300 milligrams per day

Related: Are Artificial Flavors Bad For You?

Cancer and Low Sodium Levels: A Warning Sign

Low sodium levels, or hyponatremia, are common but not universal in several types of cancer. Hyponatremia is the result of cancer cells absorbing elevated amounts of sodium from extracellular fluid. In most cases, patients receive a diagnosis of hyponatremia when blood serum sodium levels are mild (130-135 mmol/L), moderate (120-129), and severe (<120).  Hyponatremia symptoms vary, but typically include:

  • Fever
  • Nausea
  • Confusion
  • Fatigue
  • Seizures

Hyponatremia isn’t always a sign of cancer, of course. Natural blood sodium levels vary by individual, diet, and other factors. Older adults are more likely to experience hyponatremia because they tend to take medication that elevates their risk. 

What Type of Cancer Causes Low Sodium Levels?

Low sodium levels and lung cancer have the closest known relationship. Specifically, hyponatremia is linked to non-small lung cancer, followed by breast cancer, cancers of the head and neck, and colorectal cancer. While less prevalent, low blood sodium levels are also recorded with other cancer types. 

Low Sodium As A Diagnostic

It’s important to note that low sodium levels do not replace a comprehensive series of cancer tests, but they are useful diagnostic tools for several types of cancer. Even within hospitalized populations, individuals with hyponatremia are more likely to have cancer than those without, and they tend to have a worse overall survival rate than patients with a positive cancer diagnosis but with normal blood sodium levels. 

Low sodium levels are much more common in cancer patients receiving treatment. This is often the result of both cellular cancer behaviors, as noted above, as well as cancer-related complications and the impact of treatment. 

Can Balancing Sodium Levels Improve Cancer Survival?

Corrective medication and lifestyle changes require additional study. While more research is needed, there is some evidence that treating hyponatremia can improve patient quality of life and may lead to positive treatment outcomes. Still, the simple and accessible treatment (intravenous infusion of saline solution with 3% sodium chloride) is a low-risk option for medical experts, as long as the patient has a strong history of renal health. 

Decoding Sodium and Cancer with Prevention in Mind

High sodium intake contributes to cancer risk, while low sodium levels serve as a cancer warning sign. The contrasting factors are yet another sign of cancer’s complex impact on the human body. At Less Cancer, we’re working to decode sodium’s impact on human health by supporting cancer-focused programming and prevention-first initiatives across the US. Learn more about our work to make the world a healthier place, and consider donating to our cause today!