Vitamin A
The gene regulator. Vitamin A controls over 500 genes affecting vision, immunity, skin, and development. True vitamin A (retinol) is only found in animal foods.
🔬 Forms of Vitamin A
Preformed (Retinoids)
True vitamin A, ready to use. Only in animal foods.
- Retinol - Storage form, in liver
- Retinal - Vision (rhodopsin)
- Retinoic Acid - Gene regulation
Sources: Liver, egg yolks, dairy, cod liver oil
Provitamin A (Carotenoids)
Must be converted to retinol. Conversion varies widely.
- Beta-carotene - Most common
- Alpha-carotene
- Beta-cryptoxanthin
Sources: Carrots, sweet potato, leafy greens
⚠️ The Conversion Problem
Many people poorly convert beta-carotene to retinol. You may need 12-24x more carotenoids to equal retinol:
Poor Converters
- • BCMO1 gene variants (common)
- • Hypothyroidism
- • Diabetes/insulin resistance
- • Low fat diet (need fat for absorption)
- • Gut issues
Signs You're a Poor Converter
- • Yellow/orange palms (carotenemia)
- • Dry skin despite eating carrots
- • Night vision issues
- • Thyroid problems
⚡ What Vitamin A Does
Vision
Retinal forms rhodopsin for low-light vision
Immunity
Maintains mucosal barriers, T cell function
Skin/Epithelium
Cell differentiation and turnover
Gene Expression
Retinoic acid receptors regulate 500+ genes
Thyroid
Required for thyroid hormone synthesis
Iron Metabolism
Helps mobilize iron from stores
⚖️ The Vitamin A/D Balance
Vitamins A and D share receptors and must be balanced. Excess of one can functionally deplete the other:
High A, Low D
Can cause vitamin D deficiency symptoms even with adequate D. Vitamin A antagonizes D receptors.
Ideal Ratio
Some suggest ~10:1 (A:D in IU). Traditional diets from cod liver oil maintained this balance naturally.
🔻 Deficiency Signs
- • Night blindness (early sign)
- • Dry eyes, xerophthalmia
- • Dry, rough skin
- • Poor wound healing
- • Frequent infections
- • Thyroid issues
⚠️ Toxicity Signs (Excess)
- • Headaches, nausea
- • Skin peeling
- • Hair loss
- • Bone pain
- • Liver damage (chronic)
- • Birth defects (pregnancy)
Note: Beta-carotene doesn't cause toxicity—only preformed vitamin A.
Metabolic Connections
Vitamin D
Vitamin A and D work together and must be balanced
Thyroid
Vitamin A is needed for thyroid hormone synthesis
Zinc
Required for vitamin A transport and metabolism
Iron
Vitamin A mobilizes iron from storage
Immune System
Critical for mucosal immunity and T cell function
Copper
Both needed for ceruloplasmin and iron metabolism