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Sodium

What is Sodium?

Sodium as a blood biomarker significantly influences several bodily functions. When maintained within its physiological range, sodium ensures proper nerve and muscle function, aids in maintaining fluid balance across cell membranes, and plays a vital role in the functioning of the heart and brain. It is also essential for the absorption and transport of certain nutrients and maintains the osmotic balance critical for cell health.

Hyponatremia, or low blood sodium, can result from various conditions like kidney disease, heart failure, or excessive fluid intake. This condition can lead to neurological symptoms such as headache, confusion, and fatigue, progressing to more severe complications like seizures, coma, and potentially life-threatening brain swelling. Hyponatremia affects cellular function and fluid balance, disrupting normal physiological processes.

Hypernatremia, or high blood sodium, often results from dehydration or excessive salt intake and can impair kidney function. This condition manifests as intense thirst, confusion, muscle weakness, and in severe cases, can cause neurological damage and is associated with a higher risk of mortality. Hypernatremia disrupts cellular homeostasis, leading to complications in various organ systems.

To maintain healthy blood sodium levels:

  • Stay hydrated by drinking adequate water throughout the day

  • Follow a balanced diet and be mindful of sodium intake, especially from processed and packaged foods

  • Be cautious with salt substitutes and supplements containing sodium

  • Manage underlying health conditions that may affect sodium levels, such as kidney disease or heart failure

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Measurement Units

Sodium can be measured in: mEq/L, mmol/L

Reference Ranges by Age and Gender

Reference ranges represent typical values for healthy individuals. Your healthcare provider must interpret your specific results.

Age Range Gender Unit Optimal Normal Source
All ages All genders mmol/L - 135 - 145 NHS, n.d.

Health Impact

Bone Health​

While not directly incorporated into bone structure, sodium impacts bone health indirectly. High sodium intake increases urinary calcium excretion, potentially leading to negative calcium balance and bone loss. [Teucher, 2008]

Academic References

  1. Berry DJ, Cashman KD, Dainty JR, Fairweather-Tait SJ, Flynn A, Foxall RJ, Hoogewerff JA, Jakobsen J, Majsak-Newman G, Spinks CA, and Teucher B. Sodium and bone health: impact of moderately high and low salt intakes on calcium metabolism in postmenopausal women (2008). J Bone Miner Res. DOI: 10.1359/jbmr.080408
  2. Allolio B., Annane D., Ball S., Bichet D., Nagler E., Spasovski G., and Vanholder R.. Clinical practice guideline on diagnosis and treatment of hyponatraemia (2014). European Journal of Endocrinology. DOI: 10.1530/EJE-13-1020
  3. NHS The Pathology Centre.. Urea & electrolytes (U&E) - Sodium, potassium, chloride, CO2, urea and creatinine. National Health Service. View Source

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