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

Iodine (Elemental I) vs. Vitamin B7 (Biotin / Vitamin H)

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

Comparing:
Iodine (Elemental I)
Vitamin B7 (Biotin / Vitamin H)

Iodine is an essential halogen trace element required exclusively as an essential structural component of thyroid hormones thyroxine (T4) and triiodothyronine (T3), regulating metabolic rate, cellular respiration, and fetal neurodevelopment. Adult RDA is 150 µg, with an Upper Limit of 1,100 µg/day.

View full Iodine (Elemental I) 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 Trace Halogen Element Water-Soluble Ureido-Tetrahydrothiophene Vitamin
Tolerable Upper Limit (UL)
1,100 µg / day (Avoid Wolff-Chaikoff thyroid autoregulatory shutdown) None Established (No adverse effects recorded)
Chemical Forms
Iodide (I- / Potassium Iodide KI, Potassium Iodate KIO3 in iodized salt), Molecular Iodine D-Biotin (Biologically active isomer), Biocytin (Biotinyl-lysine)
Primary Biological Function
Constituent of Thyroxine (T4, 4 iodine atoms / 65% by weight) and Triiodothyronine (T3, 3 iodine atoms / 59% by weight) Prosthetic group for Pyruvate Carboxylase (Gluconeogenesis), Acetyl-CoA Carboxylase (Fatty acid synthesis), Propionyl-CoA Carboxylase, Histone biotinylation
Deficiency Condition
Endemic Goiter (Compensatory thyroid enlargement), Congenital Hypothyroidism / Cretinism (Permanent neurodevelopmental impairment), Maternal miscarriages Alopecia (Hair loss), Erythematous scaly periorofacial rash, Brittle nails, Neurological depression / hallucinations
Top Whole Food Sources
Kombu Kelp, Nori Seaweed, Atlantic Cod, Eastern Oysters, Iodized Table Salt, Greek Yogurt, Dairy Milk, Eggs Egg Yolk, Beef Liver, Salmon, Pork Chop, Sunflower Seeds, Almonds, Sweet Potatoes
Adult RDA / RDI
150 µg / day (220 µg pregnancy / 290 µg lactation)
Iodized Salt Public Health Impact
Universal salt iodization (45–75 mg KI / kg salt) is hailed as one of the greatest global public health achievements, eradicating cretinism worldwide
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