Aldosterone

Introduction

Aldosterone is a pivotal hormone that governs the body’s electrolyte balance, fluid regulation, and blood pressure. In functional medicine, evaluating aldosterone levels can uncover underlying dysfunctions in adrenal output, cardiovascular stress, and renal performance. As a Nurse Practitioner practicing autonomously in Florida, I routinely assess this biomarker when investigating fluid retention, fatigue, hypotension, or hypertension.

What is Aldosterone?

Aldosterone is a mineralocorticoid hormone secreted by the adrenal cortex in response to activation of the renin-angiotensin-aldosterone system (RAAS). It promotes sodium retention, potassium excretion, and water reabsorption, influencing both electrolyte levels and vascular tone.

Its secretion is stimulated by:

• Low serum sodium
  
• High serum potassium
  
• ACTH (Adrenocorticotropic Hormone)
  
• Low blood pressure or blood volume
  
  

Normal and Optimal Ranges

• Upright position: 5–30 ng/dL (0.14–0.80 nmol/L)
  
• Supine position: 3–10 ng/dL (0.083–0.277 nmol/L)
  
• Optimal morning range (upright draw): 4.00–14.00 ng/dL (0.11–0.39 nmol/L)
  
  

Clinical Implications of Low Aldosterone

Addison’s Disease

Adrenal insufficiency reduces aldosterone and cortisol production, leading to hyponatremia, hyperkalemia, and hypotension.

Electrolyte Imbalance

Low aldosterone may result in hypernatremia or hypokalemia.

High Salt Intake

Dietary sodium suppresses aldosterone secretion and alters blood pressure control.

Licorice Intake

Licorice can inhibit 11β-HSD2, mimicking aldosterone effects and suppressing endogenous production.

Clinical Implications of High Aldosterone

Primary Aldosteronism

Autonomous adrenal overproduction of aldosterone (e.g., adenoma or hyperplasia) results in hypertension, hypokalemia, and metabolic alkalosis.

Edema and Fluid Overload

Seen in congestive heart failure, nephrotic syndrome, and liver cirrhosis, where RAAS activation leads to excess aldosterone.

Secondary Aldosteronism

Triggered by factors like diuretic use, hyponatremia, pregnancy, or adrenal stress.

Sleep Apnea

Chronic hypoxia may upregulate RAAS, contributing to resistant hypertension and aldosterone excess.

Interfering Factors and Drug Effects

Drugs That May Increase Aldosterone

• Diuretics
  
• Laxatives
  
• Oral contraceptives
  
• Diazoxide
  
  

Drugs That May Decrease Aldosterone

• ACE inhibitors (e.g., captopril)
  
• Fludrocortisone
  
• Propranolol
  
  

Screening and Diagnosis

A morning upright aldosterone level is often the first step. For suspected primary aldosteronism, the aldosterone-to-renin ratio (ARR) is the preferred screening method.

Confirmatory tests include:

• 24-hour urine aldosterone
  
• Sodium loading tests
  
• Imaging of adrenal glands if PA is confirmed
  
  

Lifestyle and Aldosterone

• Low-Salt Diets: May increase aldosterone but also raise insulin resistance.
  
• Excessive Exercise: Can stimulate adrenal secretion of aldosterone, especially in endurance athletes.
  
• Stress and Adrenal Dysfunction: Cortisol and aldosterone are both elevated during chronic stress.
  
  

Conclusion

Aldosterone is a critical hormone in regulating electrolyte and fluid balance. Its dysregulation is implicated in conditions such as adrenal insufficiency, electrolyte disorders, cardiovascular dysfunction, and renal disease. Functional and allopathic approaches together allow for personalized treatment strategies, lifestyle modifications, and precise supplementation.

Further Reading

1. PubMed: Aldosterone Regulation and Function
   
2. PubMed: Renin-Angiotensin-Aldosterone System Overview
3. PubMed: Hyperaldosteronism Screening and Diagnosis