Vitamins are complex "organic" (ones that contain carbon molecules) substances that the body cannot make on its own but that it requires in small amounts for a number of important bodily functions.
Scientists have identified thirteen vitamins:
Vitamins are divided into two groups: fat-soluble and water-soluble:
Stored in body fat, principally in the liver
Too much vitamin A can result in: loss of appetite, headaches, irritability, liver damage, bone pain, and neurological problems, including brain damage
While vitamin A is only found in animals, dark orange-yellow and green leafy vegetables contain carotenes (e.g., beta-carotene) that the body can use to make vitamin A. Unlike vitamin A, carotene is fairly safe when consumed in large amounts because the body stores excess carotenes (which can make the skin look yellow-orange) rather than converting them to vitamin A.