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

Calcium (Elemental Ca) vs. Vitamin B3 (Niacin / Nicotinic Acid & Nicotinamide)

Comparing 2 standards across 9 specifications. 9 key differences identified.

Comparing:
Calcium (Elemental Ca)
Vitamin B3 (Niacin / Nicotinic Acid & Nicotinamide)

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 B3 comprises nicotinic acid and nicotinamide, precursors to NAD+ and NADP+ coenzymes central to over 400 enzymatic cellular reactions and DNA repair by PARP enzymes. Adult RDA is 16 mg NE (men) / 14 mg NE (women), with a Tolerable Upper Limit of 35 mg/day.

View full Vitamin B3 (Niacin / Nicotinic Acid & Nicotinamide) spec sheet →

Specification Comparison Table

9 Parameters
Parameter / Spec
Nutrient Type
Essential Macromineral Water-Soluble Pyridine Vitamin
Adult RDA / RDI
1,000 mg / day (Men 19–70, Women 19–50) / 1,200 mg (Women 51+, Men 71+) 16 mg NE / day (Men) / 14 mg NE / day (Women) (NE = Niacin Equivalents)
Tolerable Upper Limit (UL)
2,500 mg / day (Adults 19–50) / 2,000 mg / day (Adults 51+) (Avoid nephrolithiasis / vascular calcification) 35 mg / day (Supplemental nicotinic acid; prevents prostaglandin flushing)
Chemical Forms
Calcium Carbonate (40% elemental Ca / requires stomach acid), Calcium Citrate (21% elemental Ca / acid-independent), Hydroxyapatite Nicotinamide (Niacinamide), Nicotinic Acid, Nicotinamide Riboside (NR), Nicotinamide Mononucleotide (NMN)
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 NAD+/NADH redox electron carrier in glycolysis/TCA cycle, NADP+/NADPH reductive biosynthesis, PARP-1 DNA repair, Sirtuin activation
Deficiency Condition
Osteoporosis, Osteopenia, Rickets (children), Tetany (Trousseau's and Chvostek's signs of hypocalcemia) Pellagra ('The 4 Ds': Diarrhea, Dermatitis on sun-exposed skin, Dementia, Death)
Top Whole Food Sources
Parmigiano-Reggiano, Sharp Cheddar, Whole Milk, Sardines with bones, Kale, Tofu (Calcium-set), Fortified Plant Milk Chicken Breast, Canned Tuna, Salmon, Beef, Turkey, Peanuts, Brown Rice, Shiitake Mushrooms
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
Tryptophan Biosynthesis Pathway
60 mg of dietary amino acid L-tryptophan converts endogenously into 1 mg of niacin (1 NE)