[xtian]

Vitamin A is a fat-soluble vitamin.
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, usual 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.
Function
Vitamin A helps form and maintain healthy skin, teeth, skeletal and soft tissue, mucus membranes, and skin. It is also known as retinol because it produces the pigments in the retina of the eye.
Vitamin A promotes good vision, especially in low light. It may also be needed for reproduction and breast-feeding.
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.
? Beta-carotene supplements do not seem to reduce cancer risk.
Food Sources
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.