Difference between revisions of "Vitamin A"

Revision as of 09:12, 27 September 2013

Other Names: 3-Dehydroretinol, 3-Déhydrorétinol, Acétate de Rétinol, Antixerophthalmic Vitamin, Axerophtholum, Dehydroretinol, Déhydrorétinol, Fat-Soluble Vitamin, Oleovitamin A, Palmitate de Rétinol, Retinoids, Rétinoïdes, Retinol, Rétinol, Retinol Acetate, Retinol Palmitate, Retinyl Acetate, Rétinyl Acétate, Retinyl Palmitate, Rétinyl Palmitate, Vitamin A Acetate, Vitamin A Palmitate, Vitamin A1, Vitamin A2, Vitamina A, Vitamine A, Vitamine A1, Vitamine A2, Vitamine Liposoluble, Vitaminum A.
Is a yellow, fat-soluble vitamin found in egg yolks and the livers of many animals. Vitamin A and beta-carotene are closely related nutrients. The difference is that all vitamin A is preformed—and comes from animal sources (meat, eggs, milk, cheese), while beta carotene is a precursor of vitamin A (also called Provitamin A), which means that it comes in a form that the body converts to retinol by normal metabolic processes. Beta carotene comes from fruits and vegetables such as sweet potatoes, carrots, kale, spinach, turnip greens, winter squash, collard greens, cilantro, and fresh thyme. Beta-Cryptoxanthin is a source of vitamin A, but about 2 times less strong than beta-carotene.

Special Precautions of Vitamin A

High doses of vitamin A can raise concerns about toxicity, because this fat-soluble vitamin accumulates in the body and tax the liver. For this reason, some practitioners prefer beta carotene, which does not accumulate in the body and is associated with fewer risks. However, those interested in using either vitamin A or beta carotene for cancer treatment or prevention should consult with a health practitioner knowledgeable about these nutritional therapies for guidance with the best forms and dosages, as well as possible combination therapies to enhance effectiveness.

• Some scientific research suggests that higher doses might increase the risk of osteoporosis and hip fracture, particularly in older people. Adults who eat low-fat dairy products, which are fortified with vitamin A, and a lot of fruits and vegetables usually don’t need vitamin A supplements or multivitamins that contain vitamin A.
• Long-term use of large amounts of vitamin A might cause serious side effects including fatigue, irritability, mental changes, anorexia, stomach discomfort, nausea, vomiting, mild fever, excessive sweating, and many other side effects. In women who have passed menopause, taking too much vitamin A can increase the risk of osteoporosis and hip fracture.
• There is growing concern that taking high doses of antioxidant supplements such as vitamin A might do more harm than good. Some research shows that taking high doses of vitamin A supplements might increase the chance of death from all causes and possibly other serious side effects.
• Vitamin A is likely safe for children when taken in the recommended amounts. When amounts greater than those recommended are taken, side effects can include irritability, sleepiness, vomiting, diarrhea, loss of consciousness, headache, vision problems, peeling skin, increased risk of pneumonia and diarrhea, and other problems. The maximum amounts of vitamin A that are safe for children are based on age:
  • Less than 2000 units/day in children up to 3 years old.
  • Less than 3000 units/day in children ages 4 to 8 years old.
  • Less than 5700 units/day in children ages 9 to 13 years old.
  • Less than 9300 units/day in children ages 14 to 18 years old.
• Pregnancy and breast-feeding: Vitamin A is LIKELY SAFE for pregnant or breast-feeding women when taken in recommended amounts of less than 10,000 units per day. Larger amounts are POSSIBLY UNSAFE. Vitamin A can cause birth defects. It’s especially important for pregnant women to monitor their intake of vitamin A from all sources during the first three months of pregnancy. Forms of vitamin A are found in several foods including animal products, primarily liver, some fortified breakfast cereals, and dietary supplements.
• Excessive use of alcohol: Drinking alcohol may increase vitamin A’s potentially harmful effects on the liver.
• A type of high cholesterol called "Type V hyperlipoproteinemia:" This condition might increase the chance of vitamin A poisoning. Don’t take vitamin A if you have this condition.
• Liver disease: Too much vitamin A might make liver disease worse. Don’t take vitamin A if you have liver disease.
• Medications for skin conditions (Retinoids) interacts with VITAMIN A
• Antibiotics (Tetracycline antibiotics) interacts with VITAMIN A
• Medications that can harm the liver (Hepatotoxic drugs) interacts with VITAMIN A
• Warfarin (Coumadin) interacts with VITAMIN A

The benefits of Vitamin A are

• This critical vitamin contributes to eye health, respiratory health, and helps build a strong immune system.
• Vitamin A has also been proven to inhibit the spread of cancer cells and to restore normal, healthy cell growth patterns. Its effects are especially potent against leukemia and certain head and neck cancers.
• vitamin A is good for the eyes since it contain retinoids and the most popular vegetable that is most known for its vitamin A content are the carrots.
• wrinkles are reduced, it erases those dark spots and it also makes your skin smooth.

Medical Disclaimer

This information is not meant to be substituted for medical advice. Always consult a medical professional regarding any medical problems and before undertaking any treatment or dietary changes.