Vitamin A: symptoms of deficiency

Although dietary deficiency of vitamin A is rare in North America and Western Europe, it is the leading cause of childhood blindness worldwide, especially in Southeast Asia, parts of Africa and Central and South America.

In a well nourished person, vitamin A stores are generally sufficient to last many months on a vitamins A-deficient diet before signs of deficiency appear.

Vitamin A structure

Protein deficiency reduces levels of retinal-binding protein, the blood carrier protein that transport vitamin A in the blood.

The initial symptoms of vitamin A deficiency are night blindness and keratinization of hair follicles. Night blindness usually becomes apparent when the patient enters a dark place or is caught in the glare of oncoming headlights while driving at night.

Continued deficiency leads to damage to eye tissue and irreversible blindness. Vitamin A deficiency interacts with other nutrients deficiencies and with infection, worsening respiratory infections or diarrhea and causing countless deaths.
Vitamin A: symptoms of deficiency