Vitamins are a group of organic food substances or nutrients found only in living things, plants and animals. Vitamins were discovered by Dutch physician, Christiaan Eijkmann, who won the 1929 Nobel prize in physiology and medicine. The word vitamin was derived from the term vitamine. The term "vitamine" was first used in 1912 by Dr. Casimir Funk, a Polish biochemist, in reference to substances that were vital to life and contained an amine.
Vitamins are divided into two classes based on their solubility. The the fat-soluble vitamins include vitamin D, vitamin E, vitamin A, and vitamin K. The water-soluble vitamins are folate (folic acid), vitamin B12, biotin, vitamin B6, niacin, thiamin, riboflavin, pantothenic acid, and vitamin C (ascorbic acid). Fat-soluble vitamins contain only carbon, hydrogen, and oxygen while water-soluble vitamins contain these three elements plus nitrogen and some-times sulfur. Fat-soluble vitamins can be stored in appreciable amounts in the body and the water-soluble vitamins cannot be stored in the body.
Vitamins are necessary in small amounts for normal metabolism and good health. Vitamins and minerals have no calories and are not an energy source, but assist in metabolizing nutrients in food and are invaluable in keeping your body running smoothly. Vitamins make it possible for other nutrients to be digested, absorbed and metabolized by the body. Vitamins are sometimes referred to as the "spark plugs" of our human machine. They are required to do many things and their excess or depletion can lead to acute and chronic disease.
Functions of vitamins in human body
Vitamins promote normal growth, provide proper metabolism, ensure good health and protect against certain diseases. Vitamin is required by the body in small amounts for metabolism, to protect health,
and for proper growth in children. Vitamins assist in the formation of hormones, blood cells, nervous-system chemicals, and genetic material. Vitamins mainly serve as catalysts for certain reactions in the body. They combine with proteins to create metabolically active enzymes that in turn produce hundreds of important chemical reactions throughout the body. The fundamentals of cells depend greatly upon vitamins. Vitamins are responsible for keeping cells strong, binding tissues, fighting infections, etc. Without vitamins our cells would not function properly and thus our organs would suffer and eventually we would no longer be able to survive. Vitamins help regulate metabolism, help convert fat and carbohydrates into energy, and assist in forming bone and tissue.
Vitamin A plays an important role in vision, bone growth, reproduction, cell division and differentiation. Vitamin B complex improves the body's resistance to stress. Aids in digestion, promotes good muscle tone, healthy skin. Vitamin B complex reduces muscle spasms, leg cramps, hand numbness and helps regulate blood pressure. Vitamin C is responsible for helping to build and maintain our tissues and strengthening our immune system. Adequate amounts of vitamin D is necessary for preventing bone loss. Vitamin E is the most effective, fat-soluble antioxidant known to occur in the human body. The main function of vitamin E is to maintain the integrity of the body's intracellular membrane by protecting its physical stability and providing a defense line against tissue damage caused by oxidation. Alpha-lipoic acid helps to neutralize the effects of free radicals on the body. Vitamin K plays an important role in blood clotting and bone metabolism (carboxylation of osteocalcin). Bioflavonoids have antioxidant, anti-inflammatory, antiallergenic, antiviral, and anti-carcinogenic properties.
Fat soluble vitamins
Vitamin A - Vitamin A is the collective name for a group of fat-soluble vitamins. The most useable form of the vitamin is retinol. Vitamin A palmitate (retinyl palmitate) and vitamin A acetate (retinyl acetate) are the principal forms used as nutritional supplements. The precursors of vitamin A (retinol) are the carotenoids (most commonly beta-carotene). Vitamin A is one of the most versatile vitamins, with roles in such diverse functions as vision, immune defenses, maintenance of body linings and skin, bone and body growth, normal cell development, and reproduction.
Vitamin D - Vitamin D actually refers to a group of steroid molecules. Vitamin D is called the sunlight vitamin because the body produces it when the sun's ultraviolet B (UVB) rays strike the skin. Vitamin D is important for the proper absorption of calcium from food. It is vital for the control of the levels of calcium in the blood and also controls the rate at which the body excretes calcium in the urine. Low levels of vitamin D and insufficient sunlight exposure are associated with osteoporosis. Maintaining sufficient vitamin D levels may help decrease the risk of several autoimmune diseases.
Vitamin E - Vitamin E is actually an umbrella term for a group of compounds called tocopherols and tocotrienols. Alpha-tocopherol is the name of the most active form of vitamin E in humans. Vitamin E is one of the many nutrients that have protective properties. The main function of vitamin E is to maintain the integrity of the body's intracellular membrane by protecting its physical stability and providing a defense line against tissue damage caused by oxidation. Vitamin E is an antioxidant that prevents free radical damage in biological membranes.
Vitamin K - Vitamin K is a group of 2-methilo-naphthoquinone derivatives. Vitamin K is involved in the carboxylation of certain glutamate residues in proteins to form gamma-carboxyglutamate residues. Vitamin K plays an important role in blood clotting and bone metabolism (carboxylation of osteocalcin). Vitamin K supplements may improve bone mass in postmenopausal women. itamin K is used to reduce risk of bleeding in liver disease, jaundice, malabsorption, or in association with long-term use of aspirin or antibiotics.