Vitamin A (Serum)

Vitamin A toxicity can occur from taking pre-formed vitamin A from sources other than plant sources.

Vitamin A deficiency may occur with chronic alcoholism, zinc deficiency, hypothyroidism, and use of laxatives.

Vitamin A deficiency may result in night blindness, impaired immunity, impaired healing, increased risk of infection, thyroid disorders, leukoplakia or keratosis.

Assess zinc status to assess if zinc deficiency has led to secondary functional deficiency of vitamin A release from liver stores.

Food sources of vitamin A include: cod liver oil, liver (turkey, beef, pork, fish and chicken), dandelion greens, fortified cereals and milk, butter, eggs, sweet potato, pumpkin, carrot, cantaloupe, mango, spinach, broccoli leaf (broccoli florets have much less), kale, and butternut.

The RDA for vitamin A is 700mcg RAE/day for women and 900 mcg RAE/day for men. This is the amount needed to prevent chronic deficiency, but more may be needed for optimal health.

These measurements are the equivalent of 2500 IU/day for women and 3000 IU/day for men of pre-formed vitamin A sources (animal sources).

The upper intake level (UL) for vitamin A in adults is set at 3,000 μg RAE/day.

Vitamin A is a group of fat-soluble vitamins which includes retinol, retinal, retinoic acid, and several provitamin A carotenoids, among which beta-carotene is the most important.

Vitamin A has multiple functions including: growth and development in infants, children and adolescents, maintenance of the immune system, and healthy vision.

Vitamin A is needed by the retina of the eye for both low-light and color vision.

Vitamin A also functions as retinoic acid, an important hormone-like growth factor for epithelial and other cells.

Other important roles that vitamin A plays in the body include: gene transcription, haematopoiesis, and antioxidant activity.