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

Calcium (Elemental Ca) vs. Vitamin B7 (Biotin / Vitamin H)

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

Comparing:
Calcium (Elemental Ca)
Vitamin B7 (Biotin / Vitamin H)

Calcium is the most abundant mineral in the human body (1.0–1.2 kg), with 99% sequestered in hydroxyapatite bone lattice and 1% tightly regulated at 8.5–10.5 mg/dL serum for cardiac contractility, nerve signaling, and blood coagulation. Adult RDA is 1,000–1,200 mg/day.

View full Calcium (Elemental Ca) spec sheet →

Vitamin B7 is an essential sulfur-containing water-soluble vitamin serving as a prosthetic group for five carboxylase enzymes in gluconeogenesis, lipogenesis, and branched-chain amino acid catabolism. Adequate Intake (AI) is 30 µg/day (no Upper Limit established).

View full Vitamin B7 (Biotin / Vitamin H) spec sheet →

Specification Comparison Table

10 Parameters
Parameter / Spec
Nutrient Type
Essential Macromineral Water-Soluble Ureido-Tetrahydrothiophene Vitamin
Tolerable Upper Limit (UL)
2,500 mg / day (Adults 19–50) / 2,000 mg / day (Adults 51+) (Avoid nephrolithiasis / vascular calcification) None Established (No adverse effects recorded)
Chemical Forms
Calcium Carbonate (40% elemental Ca / requires stomach acid), Calcium Citrate (21% elemental Ca / acid-independent), Hydroxyapatite D-Biotin (Biologically active isomer), Biocytin (Biotinyl-lysine)
Primary Biological Function
Hydroxyapatite bone/dental structure [Ca10(PO4)6(OH)2], Troponin-C actin-myosin muscle contraction, Factor IV blood clotting cascade, Exocytosis neurotransmitter release Prosthetic group for Pyruvate Carboxylase (Gluconeogenesis), Acetyl-CoA Carboxylase (Fatty acid synthesis), Propionyl-CoA Carboxylase, Histone biotinylation
Deficiency Condition
Osteoporosis, Osteopenia, Rickets (children), Tetany (Trousseau's and Chvostek's signs of hypocalcemia) Alopecia (Hair loss), Erythematous scaly periorofacial rash, Brittle nails, Neurological depression / hallucinations
Top Whole Food Sources
Parmigiano-Reggiano, Sharp Cheddar, Whole Milk, Sardines with bones, Kale, Tofu (Calcium-set), Fortified Plant Milk Egg Yolk, Beef Liver, Salmon, Pork Chop, Sunflower Seeds, Almonds, Sweet Potatoes
Adult RDA / RDI
1,000 mg / day (Men 19–70, Women 19–50) / 1,200 mg (Women 51+, Men 71+)
Parathyroid Hormone (PTH) Homeostasis
Serum Ca2+ drop triggers PTH secretion, stimulating renal 1-alpha-hydroxylase to produce active Calcitriol (1,25-OH-D3) and osteoclast bone resorption
Adult Adequate Intake (AI)
30 µg / day (35 µg during lactation)
Raw Egg White (Avidin) Interaction
Raw egg albumen contains avidin glycoprotein which binds biotin with Kd ~10^-15 M (the strongest non-covalent bond known), completely blocking absorption unless cooked