How did vitamin A get its name? A Polish biochemist, Casimir Funk, came up with the word "vitamine" in 1912. "Vita" is Latin for "life" and at the time it was thought that all these substances were amines (later proven wrong). Hence the word "vitamin". As far as vitamin A is concerned, it was just lucky enough to be the first one identified and labeled, so it got the letter "A". SOURCES Vitamin A is a fat soluble vitamin found naturally in such foods as orange and yellow fruits, vegetables such as spinach, and animal fats. Fat soluble vitamins can generally be stored in the body. In vegetables, vitamin A is found in the form of beta-carotene which is water soluble. Among other things, this means that excess of this form of vitamin A can be eliminated from the body through natural processes. When vitamin A is acquired from animal fats or egg yolks, it is taken in as the fat soluble form of vitamin A and has the potential to build up within the body, possibly to toxic levels. AFFECTS Vitamin A is normally required in steady doses to help maintain healthy skin and good eyesight. We have all heard about eating carrots to get vitamin A which will help prevent night blindness. In fact, ancient Egyptian physicians commonly prescribed liver, which contains Vitamin A, to help prevent night blindness. Vitamin A is also important for proper growth in childhood. It is also recognized as an antioxidant, making it valuable for cancer prevention and anti-ageing. It also enhances the performance of the immune system. ABSORPTION Proper absorption of vitamin A requires some fat. Therefore, if you are on a restricted diet or low fat diet, you might not be getting as much benefit from your vitamin A supplement as you believe! Proper absorption also depends on a sufficient level of protein in the diet. DOSES The recommended daily dose of vitamin A is presently 3,000 to 10,000 IU (International Units), depending on age and health. Again, beta carotene is a safer form of vitamin A and can be safely taken in doses of 10,000 to 50,000 IU. DEFICIENCIES Vitamin A deficiencies can result in acne and other skin problems, growth problems in children, increased infections, and night blindness. In view of its value as an antioxidant, a vitamin A deficiency may put you at greater risk for cancer and you will lose out on any anti-ageing affects. WARNING Too much Vitamin A can result in pain in bones, joints, and the abdomen. It may produce severe lethargy, headache, nausea, menstrual difficulties, gastrointestinal problems and itching. Very high doses of vitamin A have been linked to birth defects. |
Index
