Vitamin A is also known as carotene (from plant-sources) and retinol (from animal sources). As a general rule, fruits and vegetables rich in vitamin A tend to be deep green or yellow-orange colored - the darker and richer the color, the higher the carotene content. Carotene and beta-carotene are converted to vitamin A when consumed by the human body. Animal sources are already in an active state of vitamin A.
Natural Food Sources
Apricots, asparagus, broccoli, cantaloupe, carrots, collard greens, egg yolks, fish-liver oils, kale, leaf lettuce, liver, milk and milk products, papaya, pumpkin, spinach, sweet potatoes, tomatoes, watermelon, winter squash.
This antioxidant (especially in the form of alpha carotene and beta carotene) is important for vision care and helps prevent night blindness. It is also necessary for the growth, repair and maintenance of bones, teeth, skin, hair and mucous membranes - vitamin A keeps them moist, which helps fend off infections. Beta carotene may also protect you against cancer and heart disease.
It takes some time to develop a deficiency in vitamin A - the average person has a 2-year supply stored in their liver. Night blindness (the inability of the eyes to adjust to bright light and darkness) and dry eyes may signal a vitamin A deficiency. Other symptoms include dry, itchy skin, susceptibility to respiratory infections, poor sense of taste and smell, dental cavities and a slower healing of wounds.
Toxicity only occurs with retinol - the worst that can happen from consuming too much carotene is your skin turns orange. Possible toxicity symptoms include headache, dizziness, blurred vision, fatigue, vomiting, bone pain and hair loss. A daily level of more than 50,000 units of vitamin A can lead to toxicity - difficult to achieve from food sources, but can happen with an overdose of supplements.
Recommended Dietary Allowance
Men: 1000 mcg
Women: 800 mcg