While it isn’t a vitamin, experts often group choline (pronounced “KO-leen”) in with them. It’s an essential micronutrient that works similarly to certain vitamins. Vitamins are nutrients that are found in the foods we eat. They’re needed for functions such as growth, metabolism, and nervous system activities. Often, a health-promoting diet can provide all. Very few foods naturally have vitamin D. Fatty fish such as salmon, tuna, and mackerel are among the best sources. Fortified foods like milk provide most of the vitamin D in American diets. Vitamins and minerals are micronutrients required by the body to carry out a range of normal functions. However, these micronutrients are not produced in our bodies and must be derived from the food we eat. Vitamins are organic substances that are generally classified as either fat soluble or water soluble. A vitamin is a small molecule that your body needs to carry out a certain reaction. Your body has no way to create vitamin molecules itself, so the vitamin molecules must come in through food that you eat. Vitamins are organic molecules (or a set of closely related molecules called vitamers) that are essential to an organism in small quantities for proper metabolic function. These essential nutrients cannot be synthesized in the organism in sufficient quantities for survival, and therefore must be obtained through consumption. All vertebrates, including humans, require dietary sources of vitamin A, vitamin D, thiamin, riboflavin, vitamin B 6, and pantothenic acid; some vertebrates, particularly the more highly evolved ones, have additional requirements for other vitamins. Learn about the functions that each vitamin and mineral performs in the body. Discover what minerals your body needs to stay healthy and work properly. Learn what vitamins your body needs and where to find them in foods. Explore an A to Z list of fact sheets for vitamin and mineral supplements. One type comes from animal sources of food. It helps you see at night, make red blood cells, and fight off infections. The other type is in plant foods. It helps prevent damage to cells and an eye. There are 13 essential vitamins. This means that these vitamins are required for the body to work properly. They are: Vitamins are grouped into two categories: Fat-soluble vitamins are stored in the body's liver, fatty tissue, and muscles. The four fat-soluble vitamins are vitamins A, D, E, and K.