Vitamin A

Definition

Vitamin A is a fat-soluble vitamin essential for vision, immune function, and skin health. It exists in two main forms: preformed vitamin A (retinol) and provitamin A carotenoids (beta-carotene).

5 Must Know Facts For Your Next Test

1. Vitamin A is crucial for maintaining healthy vision, particularly night vision.
2. Deficiency in Vitamin A can lead to xerophthalmia, which can cause blindness.
3. Beta-carotene, a precursor to Vitamin A, is an antioxidant found in colorful fruits and vegetables.
4. Vitamin A supports skin integrity by promoting cell growth and differentiation.
5. Excessive intake of preformed Vitamin A (retinol) can be toxic and lead to hypervitaminosis A.

Review Questions

• What are the two main forms of Vitamin A?
• How does a deficiency in Vitamin A affect vision?
• Why is beta-carotene important as a precursor to Vitamin A?

Related terms

Carotenoids:

Plant pigments that are precursors to Vitamin A and have antioxidant properties.

Retinol:

The active form of Vitamin A found in animal products like liver and dairy.

Hypervitaminosis A: Toxic condition caused by excessive intake of preformed Vitamin A, leading to symptoms like headaches and liver damage.