Ads
related to: retinol vitamin a function test
Search results
Results From The WOW.Com Content Network
Vitamin A occurs as two principal forms in foods: A) retinoids, found in animal-sourced foods, either as retinol or bound to a fatty acid to become a retinyl ester, and B) the carotenoids α-carotene (alpha-carotene), β-carotene, γ-carotene (gamma-carotene), and the xanthophyll beta-cryptoxanthin (all of which contain β-ionone rings) that ...
Toxicity results from ingesting too much preformed vitamin A from foods (such as liver), supplements, or prescription medications and can be prevented by ingesting no more than the recommended daily amount. Diagnosis can be difficult, as serum retinol is not sensitive to toxic levels of vitamin A, but there are effective tests available.
Retinol, also called vitamin A 1, is a fat-soluble vitamin in the vitamin A family that is found in food and used as a dietary supplement. [3] Retinol or other forms of vitamin A are needed for vision, cellular development, maintenance of skin and mucous membranes, immune function and reproductive development. [3]
Retinol-binding protein 4 has been a drug target for eye diseases as RBP4 is the sole carrier for retinol, which is an essential nutrient for the visual cycle. Animal studies using RBP4-antagonists showed that lowering RBP4 can lead to reduction in the accumulation of lipofuscin that leads to vision loss in eye diseases like Stargardt's disease ...
Vitamin A is necessary for proper functioning of the human eye. The photopigment rhodopsin found in human rod cells is composed of retinal, a form of vitamin A, bound to an opsin protein. [35] Upon the absorption of light rhodopsin was decomposed into retinal and opsin through bleaching. [35]
Vitamin A in food exists either as preformed retinol – an active form of vitamin A – found in animal liver, dairy and egg products, and some fortified foods, or as provitamin A carotenoids, which are plant pigments digested into vitamin A after consuming carotenoid-rich plant foods, typically in red, orange, or yellow colors. [28]
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Retinal was originally called retinene, [3] and was renamed [4] after it was discovered to be vitamin A aldehyde. [5] [6] Vertebrate animals ingest retinal directly from meat, or they produce retinal from carotenoids – either from α-carotene or β-carotene – both of which are carotenes. They also produce it from β-cryptoxanthin, a type of ...