• Vitamin A is found in animal products such as organ meat, full fat milk, butter, and cod liver oil. Although it’s found in a number of plants as well, the amount of vitamin A in plants is tiny compared to animal matter. When it comes to plants, however, few things beat carrots for vitamin A content.
• Carotenoids are plant pigments which aid in photosynthesis. One type of carotenoid is called beta-carotene, which is an antioxidant. Carotenoids and beta-carotene are actually named after the carrot because carrots contain so much of them. The only vegetables with more beta-carotene than carrots are dandelion greens and baked sweet potatoes. Pumpkins, apricots, leafy greens, and cantaloupe are also high in carotenoids.
• Not only do carotenoids give carrots their color, but they also act as the precursors to vitamin A. In the digestive tract, enzymes snip each carotenoid molecule in half, and the result is two molecules of vitamin A.
• Vitamin A is essential for helping the eye convert light into a signal that can be transmitted to the brain, allowing people to see in low light. Without vitamin A, the rods and cones in the retina cannot function properly, and the cornea may wither and disappear. Persistent lack of vitamin A results in night blindness, and a prolonged deficiency can result in permanent blindness.
• Eating more carrots will not improve eyesight, unless poor eyesight is caused by a vitamin A deficiency.
• Vitamin A also plays an important role in keeping the immune system vigorous and healthy. However, taking extra vitamin A won’t help if there is already enough vitamin A in the diet. In fact, overdosing on it can be fatal.
• Some vitamins, such as vitamin C and also the B vitamins, are water-soluble, meaning they are flushed out of the body and need to be constantly replenished. Other vitamins such as vitamin A and vitamin D are fat-soluble, and are stored in the body. Vitamin A is stored in the liver which typically contains about 300 international units of vitamin A for every gram of liver. But some animals, particularly those living in arctic regions, concentrate vitamin A at far greater levels. The liver of a polar bear might contain 20,000 international units per gram.
• Overdosing on vitamin A can lead to illness and death. Sometimes early Arctic explorers attempting to stave off starvation ate the liver of polar bears, seals, or their own sled dogs, all of which contained extraordinarily high levels of vitamin A. Sometimes they died.
• Because vitamin A is stored in the liver, the human body can usually survive up to a year without any vitamin A at all. But after that, a person who is not getting vitamin A will first experience night blindness and then go blind entirely. This problem is particularly prevalent in sub-Saharan Africa and South Asia. The World Health Organization estimates that between 500,000 and a million children go blind every year, and up to 90% die of complications related to vitamin deficiency. Over 70 countries have programs to deliver vitamin A supplements to reduce child mortality and blindness.
• A single serving of 3.5 ounces (about ¾ of a cup, or 100 g) of carrot yields over 100% of the recommended daily dose of vitamin A.
• One square yard of U.S. carrot production is adequate to fulfill the vitamin A needs for one adult for one entire year. 30% of American vitamin A intake comes from carrots.
