Boost Your Immune System With Vitamin A
Vitamin A is a generic term for a large number of related compounds. Retinol (an alcohol) and retinal (an aldehyde) are often referred to as preformed vitamin A. Retinal can be converted by the body to retinoic acid, the form of vitamin A known to affect gene transcription. Retinol, retinal, retinoic acid, and related compounds are known as retinoids. Beta-carotene and other carotenoids that can be converted by the body into retinol are referred to as provitamin A carotenoids. Hundreds of different carotenoids are synthesized by plants, but only about 10% of them are provitamin A carotenoids.
Retinoic acid (RA) and its isomers act as hormones to affect gene expression and thereby influence numerous physiological processes. Vitamin A and RA is found only in foods of animal origin, some fruits and vegetables contain compounds, called cartenoids that can be converted into vitamin A by your body. Food sources of preformed vitamin A include calf liver, milk, and eggs.
Vitamin A, identified in 1913, was the first fat-soluble vitamin to be discovered. A light yellow crystalline compound, vitamin A is also given the name retinol in reference to the participation of this compound in the functions of the retina of the eye. Vitamin A has also been called the “anti-infective” vitamin due to its role in supporting the activities of the immune system.
Retinoids, such as retinal and retinoic acid, are found in animal sources like liver, kidney, and dairy produce. Carotenoids like beta-carotene (which has the highest vitamin A activity) are found in plants such as dark or yellow vegetables and carrots.
Natural retinoids are present in all living organisms, either as preformed Vitamin A or as carotenoids, and are required for a vast number of biological processes like vision and cellular growth. A major biologic function of vitamin A (as the metabolite retinal) is in the visual cycle. Research also suggests that vitamin A may reduce the mortality rate from measles, prevent some types of cancer, aid in growth and development, and improve immune function.
Vitamin A Palmitate can be found in capsule, tablet, and softgel forms in both retinol and beta-carotene forms. It is recommended that name brands be purchased to ensure quality and purity of the product you buy. Look to your local or internet health food store to ensure quality and purity of the product you purchase.
*Statements contained herein have not been evaluated by the Food and Drug Administration. Vitamins and herbs are not intended to diagnose, treat and cure or prevent disease. Always consult with your professional health care provider before changing any medication or adding Vitamins to medications.
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