# item.guide
Side-by-Side Comparison Essential Vitamins & Minerals

Potassium (Elemental K) vs. Vitamin D3 (Cholecalciferol)

Comparing 2 standards across 10 specifications. 10 key differences identified.

Comparing:
Potassium (Elemental K)
Vitamin D3 (Cholecalciferol)

Potassium is the primary intracellular cation (140 mEq/L intracellular vs 4 mEq/L extracellular), maintaining the cellular resting membrane potential via the Na+/K+-ATPase pump and regulating vascular tone. Adequate Intake (AI) is 3,400 mg (men) / 2,600 mg (women).

View full Potassium (Elemental K) spec sheet →

Vitamin D3 is a secosteroid prohormone synthesized endogenously in skin via solar UVB irradiation of 7-dehydrocholesterol. Adult RDA is 600–800 IU (15–20µg), with a Tolerable Upper Limit of 4,000 IU (100µg)/day, regulating systemic calcium absorption and immune gene expression.

View full Vitamin D3 (Cholecalciferol) spec sheet →

Specification Comparison Table

10 Parameters
Parameter / Spec
Nutrient Type
Essential Macromineral / Major Intracellular Electrolyte Fat-Soluble Secosteroid Prohormone
Tolerable Upper Limit (UL)
None Established (Whole foods; healthy kidneys clear excess; renal impairment requires clinical restriction) 4,000 IU / day (100 µg) (Endocrine Society: up to 10,000 IU safe)
Chemical Forms
Potassium Citrate, Potassium Chloride (KCl / Salt substitute), Potassium Gluconate Cholecalciferol (D3 - Animal/Lichen), Ergocalciferol (D2 - Fungi)
Primary Biological Function
Na+/K+-ATPase resting membrane potential (-70mV), Cardiac myocardial repolarization, Endothelial nitric oxide vasodilation (lowers blood pressure), Blunts sodium-induced fluid retention Calcitriol receptor (VDR) activation, intestinal calcium/phosphorus absorption, antimicrobial peptide synthesis
Deficiency Condition
Hypokalemia (Serum K+ < 3.5 mmol/L): Cardiac arrhythmias (U-waves, ventricular tachycardia), Muscle weakness, Ileus, Hypertension Rickets (children), Osteomalacia (adults), Immune dysregulation
Top Whole Food Sources
Baked Russet Potato (with skin), Orange Sweet Potato, Spinach, Bananas, Atlantic Salmon, Black Beans, Hass Avocado, Coconut Water Sunlight UVB, Atlantic Salmon, Sardines, Egg Yolk, Fortified Milk
Adult Adequate Intake (AI)
3,400 mg / day (Men) / 2,600 mg / day (Women) (WHO Target: >3,510 mg/day)
Dietary Sodium-to-Potassium Ratio
Ancestral human ratio was 1:4 (Na:K); modern Western diets average 2:1, significantly contributing to hypertension
Adult RDA / RDI
600 – 800 IU / day (15 – 20 µg)
Target Serum 25(OH)D Level
30 – 50 ng / mL (75 – 125 nmol / L)