What Is Sodium Deficiency?

  • Yue Qi Master of Science - MS, Pharmacology, UCL
  • James Elliott B.Sc. (Hons), B.Ed. (Hons), PGCE, CELTA , FSB, MMCA


Sodium’s importance extends beyond mere taste enhancement in food – sodium plays a big part in influencing essential bodily functions and is crucial in maintaining various physiological processes within the human body. As a primary electrolyte, sodium regulates fluid balance, transmits nerve impulses, and supports muscle contraction.1 In this article, we will explore sodium's critical role in bodily functions and outline the health implications of sodium deficiency, providing relevant references.

Sodium is a mineral that maintains a delicate equilibrium within the human body. It serves as an electrolyte because sodium carries an electric charge when dissolved in body fluids. This charge is part of its function in several vital physiological processes. Chief among these is the maintenance of fluid balance. The sodium concentration in and around cells influences the movement of water, ensuring cells remain hydrated and function optimally.

Furthermore, sodium is integral to nerve transmission. Neurons, (nerve cells) communicate with each other and other cells in the body by transmitting electrical signals. The sodium-potassium pump, a cellular mechanism, establishes a controlled sodium-potassium imbalance, or gradient, between the inside and outside of the nerve cell by regulating the number of sodium and potassium ions in the cell. It is this imbalance that is the fundamental basis upon which nerve impulse generation depends, in turn facilitating muscle contraction and enabling sensory perception and brain function

An abnormality in sodium levels can give rise to many health complications. Sodium deficiency, known as hyponatremia, occurs when the body does not have enough sodium. This condition can arise due to various factors, such as excessive sweating, medical conditions such as kidney disorders, certain medications, or inadequate consumption of sodium in the diet.2

Hyponatremia produces a spectrum of symptoms, ranging from mild to severe. Initial signs might include nausea, headaches, fatigue, and muscle cramps. As the deficiency worsens, individuals might experience confusion, dizziness and in extreme cases, seizures. Severe hyponatremia can lead to brain swelling, coma, or even death.3

The role of sodium in the body

  • Essential electrolyte: sodium is an electrolyte, so carries an electric charge when dissolved in body fluids. This charge is fundamentally involved in the mechanisms of many physiological processes
    Fluid balance maintenance: sodium regulates fluid movement in and around cells, ensuring optimal hydration and function
    Nerve and muscle function: sodium's involvement in the sodium-potassium pump aids nerve impulse transmission, muscle contraction, sensory perception and brain function

Causes of sodium deficiency

  • Insufficient dietary intake of sodium-rich foods: one primary cause of sodium deficiency is having a diet low in sodium-rich sources, which can lead to an inadequate intake of this essential mineral
  • Excessive sweating and fluid loss: excessive sweating due to intense physical activity or hot weather can cause significant sodium loss because sodium is removed from the body in sweat. This can deplete sodium levels and lead to a deficiency
  • Medical conditions affecting sodium absorption or excretion: certain medical conditions, such as kidney disorders or hormonal imbalances, can disrupt the body's ability to absorb and retain sodium properly. This can also result in a sodium deficiency

Signs and symptoms of sodium deficiency

  • Fatigue and weakness:  due to its important role in maintaining cellular energy balance sodium deficiency can lead to feelings of fatigue and weakness
  • Muscle cramps and spasms: because sodium is essential for muscle contraction and relaxation, inadequate sodium levels can result in muscle cramps and spasms
  • Nausea and vomiting: sodium deficiency may lead to nausea and vomiting, possibly due to its impact on nerve signal conduction and fluid balance
  • Headaches and dizziness: sodium deficiency might cause headaches and dizziness, potentially linked to fluid balance and changes in blood pressure 
  • Confusion and irritability: severe cases of sodium deficiency can manifest as confusion and irritability, possibly due to its role in nerve transmission and brain function

Diagnosing sodium deficiency

Diagnosis involves a combination of assessments including:

  • Physical examination and medical history: healthcare professionals often begin diagnosing sodium deficiency by conducting a physical examination and reviewing the patient's medical history. Symptoms such as fatigue, muscle cramps, and confusion can provide valuable clues
  • Blood tests to measure sodium levels: blood tests, particularly serum sodium measurements, are crucial in diagnosing sodium deficiency. A lower-than-normal sodium level (hyponatremia) in the blood can indicate a sodium imbalance
  • Evaluation of underlying conditions: to understand the root cause of sodium deficiency, doctors may consider and test for underlying conditions such as kidney disorders, hormonal imbalances, or medications that could affect sodium absorption or excretion

Health risks of severe sodium deficiency

  • Hyponatremia and its complications: severe sodium deficiency, known as hyponatremia, can lead to various complications. Imbalanced fluid levels caused by hyponatremia can result in swelling of cells, leading to symptoms such as nausea, headache, and muscle cramps. Hyponatremia can cause swelling of the brain, (cerebral oedema) in extreme cases, leading to seizures, coma, and even death
  • Impact on brain function and neurological health: sodium is crucial for nerve transmission and maintaining brain function. Severe sodium deficiency can disrupt these processes, leading to confusion, irritability, and altered states of consciousness. Brain cells can swell due to water influx, affecting cognitive functions and potentially causing irreversible damage
  • Potential for seizures and coma in extreme cases: the imbalance in sodium levels can lead to over-activation of nerve cells, potentially triggering seizures. Consequences of hyponatremia can progress to a coma in the most severe instances, indicating critical neurological dysfunction

Prevention and treatment of sodium deficiency

  • Incorporating sodium-rich foods in the diet: including sodium-rich foods can help prevent sodium deficiency. Foods such as table salt, certain dairy products, and processed foods contain significant amounts of sodium. However, moderation is key to avoiding excessive sodium intake
  • Managing fluid balance and hydration: balancing fluid intake is essential for preventing sodium deficiency. Avoiding excessive fluid intake and staying hydrated can help maintain a healthy sodium balance
  • Addressing underlying medical conditions: managing underlying medical conditions such as kidney disorders or hormonal imbalances is crucial to preventing recurrent sodium deficiencies. Treating these conditions can help regulate sodium levels more effectively
  • Treatment with gradual sodium intake increase under medical supervision: for individuals with sodium deficiency, treatment often involves a controlled and gradual increase in sodium intake under medical guidance. This ensures a safe correction of sodium levels while minimising the risk of complications

Balancing Sodium Intake

Maintaining an appropriate sodium intake is crucial for overall health. While sodium is essential for a healthy body, excessive consumption can lead to health issues such as high blood pressure and cardiovascular problems. Consuming sodium in moderation ensures that sodium levels in the body remain within a healthy range. Finding the right balance is vital, as sodium deficiency can lead to various health risks. whereas excessive sodium intake can contribute to hypertension and other chronic conditions. Understanding the signs of both scenarios can help people make informed dietary choices.4 The World Health Organisation suggests an intake of less than 2,000 mg of sodium per day for adults 5. These guidelines serve as a reference point for individuals to manage their sodium consumption effectively.

Special considerations in sodium deficiency

  • Athletes and people with high physical activity levels: athletes and those with high physical activity levels can experience increased sodium loss through sweat. This group must carefully maintain adequate sodium intake to prevent imbalances and related complications
  • Elderly people and sodium regulation challenges: older individuals may become increasingly susceptible to sodium deficiency due to changes in kidney function and hormonal balance with age. Monitoring sodium intake becomes important in order to avoid associated health risks6
  • Impact of sodium deficiency on specific medical conditions: certain medical conditions can exacerbate the effects of sodium deficiency. For instance, heart failure patients might have a higher risk of hyponatremia, which can further strain the cardiovascular system. Understanding how sodium deficiency interacts with existing conditions is crucial for proper management


Sodium deficiency, or hyponatremia, can significantly affect various physiological functions, including fluid balance, nerve transmission, and muscle function. The symptoms of sodium deficiency range from fatigue to muscle cramps, confusion and even life-threatening conditions such as seizures and coma. Understanding the role of sodium in the body is crucial for maintaining overall health. Both inadequate and excessive sodium intake can have detrimental effects. Recognising the signs of sodium deficiency and taking steps to prevent or treat it are essential for promoting well-being and preventing related health complications.

If you suspect sodium deficiency, seeking medical advice is of paramount importance. Proper diagnosis, often through blood tests, can guide appropriate treatment strategies. Balancing sodium intake, considering individual needs, and addressing underlying conditions are vital steps in achieving and maintaining a healthy sodium balance. Athletes, older groups and those with medical conditions require special consideration. Staying informed about sodium's significance and its potential impacts on health, empowers people to make informed choices that support their wellbeing and overall quality of life.


  1. Hurley S, Alan Kim Johnson. The biopsychology of salt hunger and sodium deficiency. Pflügers Archiv: European Journal of Physiology [Internet]. 2015 Jan 10 [cited 2023 Aug 31];467(3):445–56. Available from: https://pubmed.ncbi.nlm.nih.gov/25572931/
  2. Adrogué HJ, Madias NE. Hyponatremia. The New England Journal of Medicine [Internet]. 2000 May 25 [cited 2023 Aug 31];342(21):1581–9. Available from: https://pubmed.ncbi.nlm.nih.gov/10824078/
  3. Upadhyay A, Jaber BL, Madias NE. Incidence and Prevalence of Hyponatremia. The American Journal of Medicine [Internet]. 2006 Jul 1 [cited 2023 Aug 31];119(7):S30–5. Available from: https://pubmed.ncbi.nlm.nih.gov/16843082/
  4. He FJ, MacGregor GA. Salt reduction lowers cardiovascular risk: meta-analysis of outcome trials. The Lancet [Internet]. 2011 Jul 1 [cited 2023 Aug 31];378(9789):380–2. Available from: https://pubmed.ncbi.nlm.nih.gov/21803192/
  5. World Health Organization. Guideline [Internet]. 2015 [cited 2023 Aug 31]. Available from: https://www.who.int/publications/i/item/9789241504836
  6. Roussel R, Leopold Fezeu, Bouby N, Balkau B, Lantieri O, François Alhenc-Gelas, et al. Low Water Intake and Risk for New-Onset Hyperglycemia. Diabetes Care [Internet]. 2011 Nov 14 [cited 2023 Aug 31];34(12):2551–4. Available from: https://pubmed.ncbi.nlm.nih.gov/21994426/
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Gabriel Theophilus

MPH – University of Debrecen

Theophilus is a dedicated researcher with a vital Public Health and Zoology foundation. His passion lies in unravelling the intricate connections between nutrition, lifestyle, and cardiometabolic diseases. Theophilus has collaborated on diverse research projects, from systematic reviews to animal studies, highlighting his meticulous approach and technical acumen. Theophilus is dedicated to advancing scientific understanding in nutrition and health, focusing on improving the well-being of diverse populations.

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