Vitamin A is a fat-soluble vitamin that helps form and maintain healthy skin, teeth,mucus membranes, skeletal and soft tissue. Vitamin A promotes good vision, especially in low light. It may also be needed for reproduction and breast-feeding.
Scientific/medical names include: Vitamin A, alpha carotene, retinol, retinoic acid, retinyl palmitate, retinoids, beta carotene and beta-cryptoxanthin.
Two different types of vitamin A are found in the diet. Preformed vitamin A is found in animal products such as meat, fish, poultry and dairy foods. The other type, pro-vitamin A is found in plant-based foods such as fruits and vegetables. The most common type of pro-vitamin A is beta-carotene.
Vitamin A is also available in dietary supplements, usually in the form of retinyl acetate or retinyl palmitate (preformed vitamin A), beta-carotene (pro-vitamin A) or a combination of preformed and pro-vitamin A.
Alternative Names: Retinol, Retinal, Retinoic acid, Carotenoids
Vitamin A is known as retinol, because it produces the pigments in the retina of the eye.
Retinol is an active form of vitamin A. It is found in animal liver, whole milk, and some fortified foods.
Carotenoids are dark-colored dyes (pigments) found in plant foods that can turn into a form of vitamin A. There are more than 500 known carotenoids. One such carotenoid is beta-carotene.
Beta-carotene is an antioxidant. Antioxidants protect cells from damage caused by substances called free radicals. Free radicals are believed to contribute to certain chronic diseases and play a role in the aging processes.
Food sources of carotenoids such as beta-carotene may reduce the risk for cancer.
Vitamin A comes from animal sources, such as eggs, meat, fortified milk, cheese, cream, liver, kidney, cod, and halibut fish oil. However, all of these sources – except for skim milk that has been fortified with Vitamin A – are high in saturated fat and cholesterol.
Sources of beta-carotene include: Bright yellow and orange fruits such as cantaloupe, pink grapefruit, and apricots. Vegetables such as carrots, pumpkin, sweet potatoes, and winter squash. Other sources of beta-carotene include broccoli, spinach, and most dark green, leafy vegetables.
The more intense the color of a fruit or vegetable, the higher the beta-carotene content. Vegetable sources of beta-carotene are fat and cholesterol-free.
If you don’t get enough vitamin A, you are more likely to get infectious diseases and vision problems. Vegetarians, young children, and alcoholics may need extra Vitamin A. You might also need more if you have certain conditions, such as liver diseases, cystic fibrosis, and Crohn’s disease. Check with your health care provider to see if you need to take vitamin A supplements.
If you get too much vitamin A, you can become sick. Large doses of vitamin A can also cause birth defects.
Acute vitamin A poisoning usually occurs when an adult takes several hundred thousand IUs of vitamin A. Symptoms of chronic vitamin A poisoning may occur in adults who regularly take more than 25,000 IU a day. Babies and children are more sensitive to vitamin A and can become sick after taking smaller doses of vitamin A or vitamin A-containing products such as retinol as found in skin creams.
Large amounts of beta-carotene will not make you sick; however, increased amounts of beta-carotene can turn the skin yellow or orange. The skin color will return to normal once you reduce your intake of beta-carotene.