Vitamins are organic substances essential in small amounts for the body's normal growth and activity. They are obtained naturally from plant and animal foods. Vitamins have two classifications, fat- or water-soluble, depending on the materials in which they dissolve. Fat-Soluble Vitamins: Fat-soluble vitamins include A, D, E and K. These vitamins are stored in the body's fat tissues before they are absorbed in the blood stream. Because the body stores these vitamins, it is not always necessary to get a fresh supply each day. Caution should be used when taking fat-soluble vitamins to avoid the potential of harmful, toxic levels. Fat-soluble vitamins are required for the maintenance of healthy bones, skin and hair and for bringing nourishment to the cells. Vitamin A is essential for vision, especially night vision. Vitamin K is essential for the formation of blood-clotting proteins. The major dietary sources of these vitamins are green leafy vegetables, deep orange or yellow fruits and vegetables, cod liver oil, sardines, butter, egg yolks, fortified milk, almonds, wheat germ, peanut butter, corn oil, sunflower seeds, and liver. Water-Soluble Vitamins: Water-soluble vitamins include B1, B2, B3, B6, B12 and vitamin C, as well as folic acid and biotin. Water-soluble vitamins, unlike fat-soluble vitamins, are not easily stored in the body and are often lost from foods in the cooking process. It is therefore important to include these vitamins in a daily dietary regimen. B vitamins are involved in fat and protein breakdown. The B vitamins are required for healthy nervous system function, healthy skin, hair, eyes and liver function. Some of the B vitamins require other B vitamins to work correctly in the body. Vitamin C (ascorbic acid) is important to the body in the production of collagen, creating connective tissue and supporting our organs. Other functions include protecting the fat-soluble vitamins and preventing scurvy. The major dietary sources of these vitamins are cereal grains, meat, poultry, eggs, fish, milk, legumes and fresh vegetables. Vitamin C is found in citrus fruits, guava, red bell pepper, papaya, orange juice, broccoli, green bell pepper, strawberries, cantaloupe, tomato juice, mango, potato, cabbage, tomato, collard greens, spinach, Brussels sprouts, turnip greens, cauliflower, blackberries, and blueberries.