Vitamins are essential micronutrients, or substances that the body uses in small amounts for proper functioning and metabolic activities, as compared to macronutrients, which are the proteins, fats, and carbohydrates that make up all food. Vitamins are present in food, especially in fruits, vegetables and are synthesized in the intestinal flora such as vitamins K and E.
Adequate quantities of vitamins may be affected when food is overcooked, processed, or improperly stored and intestinal activities are inhibited with antibiotics and alcohol. For instance, processing whole wheat grain into white flour reduces the contents of vitamins B and E, fiber and minerals, including zinc and iron. The loss of adequate quantities of vitamins mostly occurs in vitamins B and C because of their volatility.The body requires vitamins to support its basic biochemical functions, and deficiencies or excesses over time can lead to illness and disease. Vitamins are either water-soluble or fat-soluble. Water-soluble vitamins dissolve in water and pass through the body quickly, meaning that the body needs them on a regular basis. Water-soluble vitamins include the B-complex vitamins and vitamin C. Fat-soluble vitamins are stored in the body's fatty tissue, meaning that they remain in the body longer. Fat-soluble vitamins include vitamins A, D, E, and K. The amount of vitamins needed by the body has been the subject of much research. The U.S. government has published recommended dietary allowances (RDAs) for each vitamin for the general population. These figures can be used as guidelines, but individuals may have different needs depending on gender, age, and health conditions as well the vulnerable groups which include children, pregnant mothers, lactating mothers and the elderly.
Vitamins can be natural or synthetic. Natural vitamins are obtained from food sources, while synthetic vitamins are formulated in laboratory processes. The only vitamin for which there is a noted difference between the natural and synthetic forms is vitamin E. The natural form is labeled d-alpha-tocopherol while the synthetic form is named dl-alpha-tocopherol, with the extra "l" signifying laboratory production. Natural vitamin E has been shown to be slightly more absorbable by the body than the synthetic version, although for other vitamins no significant differences in absorption have been noted.
By - Chidebere