Vitamin A2

Vitamin A2

Vitamin A2, also known as 3,4-didehydroretinol, is one of the forms of vitamin A, which is essential for many biological processes. It is less common than retinol, but is found in certain freshwater fish species and is believed to have similar biological activity.

Structure and Properties

Vitamin A2 is a diterpenoid and is characterized by a 20-carbon structure, which is assembled from a four carbon unit. It is a polyene compound, meaning it contains multiple double bonds. The molecule has a cyclic end group, a polyene side chain, and a hydroxyl group. The presence of the double bonds allows for the absorption of light, which is critical for the vitamin's role in vision.

Biological Role

Like other forms of vitamin A, Vitamin A2 plays a crucial role in maintaining healthy vision, growth, and tissue differentiation. It is a component of the rhodopsin molecule, which is activated when light shines on the retina, signaling the brain about light changes in the environment.

Vitamin A2 also supports the health of the skin and mucous membranes, the immune system, and bone growth. Deficiency in vitamin A2 can lead to a series of health problems, including night blindness, hyperkeratosis, and increased susceptibility to infections.

Dietary Sources and Supplementation

Vitamin A2 is found in certain freshwater fish species, such as the rainbow trout. However, it is less common in the human diet compared to retinol.

Supplementation with Vitamin A2 is not common, as the body can convert dietary sources of other forms of vitamin A into the necessary retinoids. However, in cases of deficiency or certain health conditions, supplementation may be recommended under the guidance of a healthcare professional.

See Also

• Vitamin A
• Retinol
• Rhodopsin
• Vitamin deficiency