Vitamin A

Vitamin A Deep Dive

Vitamin A (Essential Fat-Soluble Vitamin)

Classification: Fat-soluble vitamin (Retinoids and Carotenoids)

Primary Roles: Rhodopsin formation for low-light vision, cellular differentiation and mucosal integrity, and regulation of gene expression.

Quick Summary

Vitamin A is a key regulator of vision, epithelial tissue health, and immune resilience. Diets low in preformed retinol and variable carotenoid conversion capacity can leave functional gaps that are not always obvious in routine clinical screening.

Core Benefits

Visual Preservation: Supports rhodopsin biology in the retina for low-light vision and helps maintain corneal hydration.
Infection Defense: Helps restore mucosal barrier integrity in the respiratory and gastrointestinal tracts.
Immune Generation: Supports T-cell development and mucosal antibody production involved in frontline immune function.

Nutrient Web

Zinc: Required for synthesis of retinol-binding protein used to transport vitamin A from liver stores.
Dietary Fat: Fat intake stimulates bile flow needed for intestinal absorption of fat-soluble vitamin A.
Vitamins D and K2: Works alongside D and K2 in broader mineral-signaling pathways related to calcium handling and tissue targeting.

Recognizing Deficiency

Poor dark adaptation and progressive night-vision difficulty
Dry, rough, or persistently scaly skin despite topical care
Increased frequency of respiratory or gut infections

How to Get It

Source Type	Best Options	Notes
Environmental/Plant superfoods	Carrots, sweet potatoes, spinach	Provide provitamin A carotenoids; conversion to active retinol varies significantly, and up to 40% of people carry a genetic variant that limits it.
Dietary staples	Egg yolks, full-fat dairy	Steady, moderate preformed retinol suited to regular, everyday intake.
Dietary support	Beef liver, cod liver oil	The most concentrated, immediately bioavailable preformed retinol; a single weekly serving covers the full requirement, ideal for topping up when plant conversion is poor.

Testing and Target Ranges

Serum retinol is homeostatically regulated and may only fall late, so interpret results with clinical context and intake pattern.

Required Test: Fasting Serum Retinol
Target Range: Typically 1.05-3.00 umol/L, with >1.05 umol/L used as a practical sufficiency floor.

Males

Age Group	RDA
9–13 years	600 mcg_rae
14–18 years	900 mcg_rae
19–30 years	900 mcg_rae
31–50 years	900 mcg_rae
50+ years	900 mcg_rae

Females

Age Group	RDA
9–13 years	600 mcg_rae
14–18 years	700 mcg_rae
19–30 years	700 mcg_rae
31–50 years	700 mcg_rae
50+ years	700 mcg_rae

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Vitamin A at a Glance