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

Vitamin B9 (Folate & Folic Acid) vs. Vitamin D3 (Cholecalciferol)

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

Comparing:
Vitamin B9 (Folate & Folic Acid)
Vitamin D3 (Cholecalciferol)
Vitamin B9 (Folate & Folic Acid) →

Vitamin B9 comprises natural dietary folates (polyglutamates) and synthetic folic acid (monoglutamate). Adult RDA is 400 µg DFE, with a Tolerable Upper Limit of 1,000 µg/day synthetic folic acid, essential as a single-carbon donor in thymidylate DNA synthesis and neural tube closure.

View full Vitamin B9 (Folate & Folic Acid) spec sheet →
Vitamin D3 (Cholecalciferol) →

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

9 Parameters
Parameter / Spec
Vitamin B9 (Folate & Folic Acid)
Vitamin D3 (Cholecalciferol)
Nutrient Type
Water-Soluble Pteroylglutamate Vitamin Fat-Soluble Secosteroid Prohormone
Adult RDA / RDI
400 µg DFE / day (600 µg DFE pregnancy / prevents neural tube defects) 600 – 800 IU / day (15 – 20 µg)
Tolerable Upper Limit (UL)
1,000 µg / day (Synthetic folic acid only; masks B12 deficiency neuropathy) 4,000 IU / day (100 µg) (Endocrine Society: up to 10,000 IU safe)
Chemical Forms
(6S)-5-Methyltetrahydrofolate (5-MTHF, active circulating form), Tetrahydrofolate (THF), Folic Acid (Pteroylmonoglutamic acid, synthetic) Cholecalciferol (D3 - Animal/Lichen), Ergocalciferol (D2 - Fungi)
Primary Biological Function
1-Carbon transfer reactions, dUMP -> dTMP methylation (Thymidine DNA synthesis), Methionine-Homocysteine cycle, Erythropoiesis Calcitriol receptor (VDR) activation, intestinal calcium/phosphorus absorption, antimicrobial peptide synthesis
Deficiency Condition
Neural Tube Defects (Spina bifida, anencephaly in fetuses), Megaloblastic Macrocytic Anemia, Elevated Homocysteine Rickets (children), Osteomalacia (adults), Immune dysregulation
Top Whole Food Sources
Beef Liver, Spinach, Asparagus, Brussels Sprouts, Roman Lentils, Chickpeas, Fortified Flours Sunlight UVB, Atlantic Salmon, Sardines, Egg Yolk, Fortified Milk
MTHFR Genetic Polymorphism
Homozygous MTHFR C677T variant reduces folate reduction activity by ~70%, benefiting from direct 5-MTHF supplementation —
Target Serum 25(OH)D Level
— 30 – 50 ng / mL (75 – 125 nmol / L)

Other Alternatives to Compare

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