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

Vitamin A (Retinol & Beta-Carotene) vs. Vitamin B12 (Cobalamin)

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

Comparing:
Vitamin A (Retinol & Beta-Carotene)
Vitamin B12 (Cobalamin)
Vitamin A (Retinol & Beta-Carotene) →

Vitamin A is an essential fat-soluble isoprenoid comprising preformed retinol and provitamin A carotenoids. Adult RDA is 900 µg RAE (men) / 700 µg RAE (women), with a Tolerable Upper Limit of 3,000 µg/day preformed retinol, essential for rhodopsin retinal photoreception, epithelial differentiation, and immune cell proliferation.

View full Vitamin A (Retinol & Beta-Carotene) spec sheet →
Vitamin B12 (Cobalamin) →

Vitamin B12 is a cobalt-containing water-soluble corrinoid synthesized exclusively by microorganisms. Adult RDA is 2.4µg/day (no Upper Limit established), required for DNA synthesis, methionine synthase homocysteine conversion, and myelin sheath maintenance.

View full Vitamin B12 (Cobalamin) spec sheet →

Specification Comparison Table

9 Parameters
Parameter / Spec
Vitamin A (Retinol & Beta-Carotene)
Vitamin B12 (Cobalamin)
Nutrient Type
Fat-Soluble Isoprenoid Vitamin Water-Soluble Corrinoid Vitamin
Adult RDA / RDI
900 µg RAE / day (Men) / 700 µg RAE / day (Women) 2.4 µg / day (2.6µg pregnancy, 2.8µg lactation)
Tolerable Upper Limit (UL)
3,000 µg / day (10,000 IU) (Preformed retinol only; no UL for beta-carotene) None Established (Extremely low toxicity)
Chemical Forms
Retinyl Palmitate (Preformed Animal), All-Trans Retinol, Beta-Carotene (Plant Provitamin) Methylcobalamin (Active), Adenosylcobalamin (Active), Cyanocobalamin (Stable synthetic)
Primary Biological Function
11-cis-retinal rhodopsin visual cycle, RAR/RXR nuclear receptor gene transcription, Mucosal barrier immunity Methionine synthase cofactor, Methylmalonyl-CoA mutase cofactor, Myelin integrity, Erythropoiesis
Deficiency Condition
Nyctalopia (Night blindness), Xerophthalmia, Bitot's spots, Keratinization of mucous membranes Pernicious / Megaloblastic Anemia, Irreversible Neurological Peripheral Neuropathy
Top Whole Food Sources
Beef Liver, Cod Liver Oil, Sweet Potatoes, Carrots, Spinach, Curly Kale, Butter Oysters, Beef Liver, Sardines, Salmon, Beef, Dairy, Eggs (Absent in unfortified plant foods)
Hepatic Storage
80–90% of total body Vitamin A is stored in hepatic stellate cells as retinyl esters —
Absorption Mechanism
— Requires Gastric Acid, R-Protein, and Intrinsic Factor (IF) via Ileal Cubam receptors

Other Alternatives to Compare

Compare Vitamin A (Retinol & Beta-Carotene) vs. Calcium (Elemental Ca) → Compare Vitamin A (Retinol & Beta-Carotene) vs. Iodine (Elemental I) → Compare Vitamin A (Retinol & Beta-Carotene) vs. Iron (Heme & Non-Heme) → Compare Vitamin A (Retinol & Beta-Carotene) vs. Magnesium (Elemental Mg) → Compare Vitamin A (Retinol & Beta-Carotene) vs. Potassium (Elemental K) → Compare Vitamin A (Retinol & Beta-Carotene) vs. Selenium (Elemental Se) → Compare Vitamin A (Retinol & Beta-Carotene) vs. Sodium (Elemental Na) → Compare Vitamin A (Retinol & Beta-Carotene) vs. Vitamin B1 (Thiamine) → Compare Vitamin A (Retinol & Beta-Carotene) vs. Vitamin B2 (Riboflavin) → Compare Vitamin A (Retinol & Beta-Carotene) vs. Vitamin B3 (Niacin / Nicotinic Acid & Nicotinamide) → Compare Vitamin A (Retinol & Beta-Carotene) vs. Vitamin B5 (Pantothenic Acid) → Compare Vitamin A (Retinol & Beta-Carotene) vs. Vitamin B6 (Pyridoxal 5'-Phosphate / PLP) → Compare Vitamin A (Retinol & Beta-Carotene) vs. Vitamin B7 (Biotin / Vitamin H) → Compare Vitamin A (Retinol & Beta-Carotene) vs. Vitamin B9 (Folate & Folic Acid) → Compare Vitamin A (Retinol & Beta-Carotene) vs. Vitamin C (L-Ascorbic Acid) → Compare Vitamin A (Retinol & Beta-Carotene) vs. Vitamin D3 (Cholecalciferol) → Compare Vitamin A (Retinol & Beta-Carotene) vs. Vitamin E (d-Alpha-Tocopherol) → Compare Vitamin A (Retinol & Beta-Carotene) vs. Vitamin K1 (Phylloquinone) → Compare Vitamin A (Retinol & Beta-Carotene) vs. Zinc (Elemental Zn) →