VITAMIN A -Bio chemical functions, Metabolism,RDA & Deficiency
Vitamin A is a fat-soluble vitamin that is naturally present in many foods.
Vitamin A is a group of unsaturated nutritional organic compounds that includes retinol, retinal, and several provitamin A carotenoids
Vitamin A is the name of a group of fat-soluble retinoids, including retinol, retinal, and retinyl esters
Vitamin A is available in dietary supplements, usually in the form of retinyl acetate or retinyl palmitate (preformed vitamin A), beta-carotene (provitamin A), or a combination of preformed and provitamin A.
Most multivitamin-mineral supplements
contain vitamin A.
Vitamin A has multiple functions: It is important for growth and development, for the maintenance of the immune system, and for good vision.
Vitamin A is important for normal vision, the immune system, and reproduction
Vitamin A also helps the heart, lungs, kidneys, and other organs work properly.
Vitamin A is involved in immune function, vision, reproduction, and cellular communication
Vitamin A is critical for vision as an essential component of rhodopsin, a protein that absorbs light in the retinal receptors, and because it supports the normal differentiation and functioning of the conjunctival membranes and cornea
Vitamin A also supports cell growth and differentiation, playing a critical role in the normal formation and maintenance of the heart, lungs, kidneys, and other organs
Vitamin A Physiological Functions
Vision
Epithelial cell “integrity’
Reproduction
Resistance to infectious disease
Bone remodeling Growth
Recommended Dietary Allowance (RDA) for vitamin A are given as retinol activity equivalents (RAE) to account for the different bioactivities of retinol and provitamin A carotenoids, all of which are converted by the body into retinol.
The Recommended Dietary Allowance (RDA) for men and women is 900 and 700 μg retinol activity equivalents (RAE)/day, respectively. The Tolerable Upper Intake Level (UL) for adults is set at 3,000 μg/day of preformed vitamin A.However, it’s important not to exceed the tolerable upper limit (UL) of 10,000 IU (3,000 mcg) for adults to prevent toxicity
Recommended dietary allowance :
Men and women – 600 mcg. Per day
Pregnancy and lactation – 950 mcg. Per day
Infants – 350 mcg. Per day
Children – 600 mcg. Per day
VITAMIN – A :-
Is widely distributed in animal and plant foods
animals –pre-formed – Retinol. plants – pro-formed – carotene
