Vitamins help to regulate the metabolic processes in the body. They are usually made up of carbon, oxygen, hydrogen, sulfur, and nitrogen. They are needed in small amounts for normal growth, maintenance and reproduction. They cannot be produced by the body. If a diet is well-balanced, usually all of the needed vitamins are provided. If not, serious vitamins deficiencies may result.
Vitamins can be either fat-soluble or water-soluble. Fat-soluble vitamins are stored in fat and they are A, D, E, and K. Vitamin A is needed for growth of bones and teeth, healthy skin tissue and is an important chemical compound for the eyes. Vitamin A is obtained in foods such as butter, fish, oils, spinach and squash. Vitamins A, C, and E are very powerful antioxidants and promote and preserve memory in the elderly ("Brain Food", 2009).
Vitamin D promotes the growth and proper mineralization of bones and teeth; it also helps the body in the use of calcium and phosphorus. Vitamin D is found in foods such as egg yolk, tuna liver, sardines and fish liver oils. Humans make 90 percent of vitamin D naturally using sunlight exposure to the skin - specifically, from ultraviolet B exposure to the skin, which initiates the conversion of cholesterol in the skin to vitamin D3. An individual probably needs from 5 to 30 minutes of exposure to the skin on the face, arms, back or legs (without sunscreen) twice every week. Since exposure to sunlight is a risk for skin cancer, a person should use sunscreen after a few minutes in the sun and even in the winter and on hazy, cloudy days (http://digghealth.com/vitamin-sun/.)
Relatively little is known about the role of vitamin E in the body, although it is believed that it does combine with oxygen, it is readily oxidized and it reduces that amount of oxygen inhibiting the oxidation of fatty acids, and carotene. It is commercially used to slow spoilage. Major sources are found in shortenings, margarines, salad oils, fats and other oils. Other sources are leafy green vegetables, breads and whole grain cereals.
Vitamin K is vital in blood clotting. It helps the liver make a substance known as prothrombin, a protein that blood needs to clot. If vitamin K is not available, he blood cannot clot properly. Vitamin K is found in leafy green vegetables, cauliflower, organ meats and egg yolks.
Vitamin C is water-soluble, it cannot be stored in the body and it must be supplied each day. Vitamin C helps in the formation and maintenance of collagen, helps make the walls of blood vessels firm, wounds heal and broken bones mend. It aids in the formation of hemoglobin and helps the body fight infection. Important sources are fresh fruit and vegetables such as citrus fruits, strawberries, cantaloupe, green peppers, broccoli and cabbage.
The B vitamins are the most complex of all and are water-soluble. Although each has its own characteristics, they all work together in the body. The B complex minerals are very important for growth and functioning of the brain. This vitamin is particularly important to the brain and plays a vital role in making energy.
B-1 (thiamin) helps promote normal appetite and digestion. Forms parts of the coenzymes needed for the breakdown of carbohydrates, keeps the nervous system healthy, and helps release energy from food.
B-2 (riboflavin) aids cells in the use of oxygen, keeps tongue and lips normal, and prevents scaly, greasy areas around the mouth and nose. Riboflavin also forms part of the coenzymes needed for the breakdown of carbohydrates in the body.
Folic acid is essential for all vertebrates, including human beings. It keeps the body producing normal blood cells and plays a part in biochemical reactions in cells whereby food is converted to energy.
Niacin helps the nervous system, skin, mouth, tongue and digestive tract stay healthy, aids cells in the use of other nutrients and forms parts of two coenzymes involved in complex chemical reactions in the body.
B-6 (pyridoxine) aids in nervous tissue functioning normally, has a role in the breakdown of proteins, fats and carbohydrates, and plays a role in the regeneration of red blood cells.
B-12 protects against anemia and plays a role in the normal functioning of cells.
Sources of vitamin B complex are liver, muscles meats, poultry, fish, other meats, eggs, ice cream, whole grain bread, cereals, milk, cheese, dried beans and peas, and leafy green vegetables.