Vitamin A Deficiency and Liquid Vitamins
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Retinol can be converted by the body to retinoic acid, the form of vitamin A known to affect gene transcription. Beta-carotene and other carotenoids can be converted by the body into retinol and are referred to as pro-vitamin A. The major functions of vitamin A in the human body are as follows: "Vision"--the retina is located in the back of the eye. When light passes through the lens, it is sensed by the retina and converted to a nerve impulse for interpretation by the brain. Retinol is transmitted to the retina via the circulation and accumulates in retinal pigment epithelial cells. Inadequate retinol available to the retina results in impaired dark adaptation known as "night vision". Vitamin A has been shown to have large impacts on the major functions of the vision process. "Immunity"--Vitamin A is also commonly known as the anti-infection vitamin, because it is required for the normal functioning of the immune process. The skin and the mucosal cells (the cells in the airways, the digestive tract, and the urinary tract) function as a barrier and form the body's first line of defense against infections. Retinol and its metabolites are required to maintain the integrity and function of those cells. Vitamin A and retinoic acid (RA) play a central role in the development and the differentiation of white blood cells. Vitamin A excess and deficiency are known to cause "birth defects". Retinol and retinoic acid (RA) are essential in embryonic development. Red blood cells, like all blood cells, are derived from precursor cells called 'stem cells". Stem cells are dependent on retinoids for the normal differentiation into red blood cells. Additionally, vitamin A appears to facilitate the mobilization of iron from storage sites to the developing red blood cells for incorporation into hemoglobin, the oxygen carrier in red blood cells. Deficiency among children in developing nations is the leading preventable cause of "blindness". The earliest deficiency is night blindness. A mild deficiency may result in changes in the conjuctiva (corner of the eye) called Bilot's spots, but vitamin A deficiency can lead to even bigger problems. A severe or a prolonged vitamin A deficiency causes a condition called dry eye, which is characterized by changes in the cells of the cornea which may result in corneal ulcers, scarring, and blindness. Vitamin A deficiency can be considered a nutritionally acquired disease. For this reason, a good liquid vitamin A supplement is a must for this vital vitamin. Even children who are mildly deficient have a higher incidence of respiratory disease and diarrhea as well as a higher rate of mortality from infectious disease as compared with children who consume sufficient vitamin A. Foods that provide sources of vitamin A include cod liver oil, fortified breakfast cereals, eggs, butter, whole milk, 2% milk and non-fat milk (vitamin D added), sweet potatoes (canned and baked), pumpkin (canned), raw carrots, cantaloupe, mango's, spinach, broccoli, kale, collards, and pumpkin squash. The principal forms of preformed vitamin A (retinol) in supplements are retinyl palmitate and retinyl acetate. Beta-carotene is also a common source of vitamin A in supplements, and many supplements provide a combination of retinol and beta-carotene. There are several very good liquid vitamins and multi-liquid vitamins in today's market including the following brands: Naturally Direct Liquid Vitamins and Vitamin A Deficiency
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