subject: Know Your Vitamin A [print this page] Vitamin A belongs to the family of commonly shaped molecules called as retinoids completing the lefts of vitamin sequence in the body. The best part of vitamin A is the retinyl group available in different forms. In many animal foods the important factor of vitamin A is known as ester called as retinyl palmitate, and which is later converted into alcohol in the smaller intestine. One should understand that vitamin A is present in aldehyde of the body. The retinoic acid which is a metabolite contains hardly any vitamin A activity do not show function in the retina of the eye. Precursors of vitamin A are already available in foods of plant origin .
Each forms of vitamin A contains beta-ionone ring by which an isoprenoid chain is joined . Vitamin A this structure is important for vitamin activity in the body. So the orange pigment of carrots - beta-carotene reflects two connected retinyl groups having the usage in the body for increasing vitamin A levels. In the same way alpha-carotene and gamma-carotene do have single retinyl group showing vitamin A activity in the body. There are several forms of vitamin A such as carotenoid beta-cryptoxanthin carrying an ionone group performing vitamin A activity in human body. One knows that retinyl group belongs to the vitamin A having a specified protein which is the light absorber in visual perception in the retina of the eye.
Consumers of Vitamin A should know that one can avail it in varied forms like retinol which is another form of vitamin A absorbed through animal food sources, yellow, fat-soluble, vitamin having role in vision and bone growth. The other form is retinoids which is a class of chemical compounds of vitamin A having the usage in medicine. The carotenes alpha-carotene, beta-carotene, gamma-carotene and the xanthophyll beta-cryptoxanthin and no other carotenoids works as vitamin A in many herbivores and omnivore animals. Mostly vitamin A is present in several foods such as liver, carrot, broccoli leaf, sweet potato, kale, butter, spinach, pumpkin and many more. Vitamin A also plays an important role in many functions such as vision, gene transcription, immune function, embryonic development and reproduction, bone metabolism, haematopoiesis, skin health, and antioxidant Activity etc.
