Vitamins (2) In the early 20th century the discovery of vitamins began. Today there is a chance that there are some vitamins that are still undiscovered. The definition of vitamin is: one of several substances necessary for animal nutrition, and occurring in minute quantities in natural foods; numerous types have been distinguished, and designated by the letters of the alphabet. Each and every living animal needs vitamins to grow and be healthy. Since the human body can t produce vitamins naturally or normally produce the amounts needed, food provides the body with them. There are different vitamins found in different foods. These vitamins give vital nutrients to an animal. In 1906, the British biochemist Sir. Frederick Hopkins demonstrated that foods contain accessory factors in addition to proteins, carbohydrates, fats, minerals and water. Then, in 1912, thee chemist Casimir Funk identified that the (3) antiberiberi substance in unpolished rice was an amine (a type of Nitrogen-containing compound), so Funk proposed that it be named vitamine, from vital amine. It was later discovered that different vitamins have different chemical properties. This discovery caused vitamine to be turned into vitamin. In 1912 Hopkins and Funk made a hypothesis. The hypothesis stated the absence of some vitamins could cause diseases such as beriberi and scurvy. Later a letter was assigned to each vitamin. The letters which were assigned to vitamins in the early years of vitamin research categorize them according to their functions. As research progressed, the vitamins were given scientific names. Foods that contain vitamins are very essential for good health and growth. Milk can be important because it is a source of vitamin D. Vitamin D is important because it is essential for bone growth. (4) Butter can be important because it is a source of Vitamin A. The pigments that are converted into Vitamin A, are found in most fruits and vegetables. Vitamin A is important because it can prevent diseases. Cereal and seeds can de important because of its source of Vitamin B. Vitamin B is important because of their source of Vitamin B. Vitamin B is important because it can prevent beriberi. Citrus Fruits can be important because of their source of vitamin C. Vitamin C is important for strength and metabolism. Plants can be important because of the plant oil which is a source of Vitamin E. Vitamin e is important because it is a source of oxidation in body tissues. (5) These examples prove that the distribution of vitamins in natural sources is uneven. Take vitamin D for example. It is produced only by animals, where as some other vitamins may only be found in plants. Vitamins can be synthetically produced or found naturally, but there is no proof that either natural or synthetic vitamins are superior to one another. There are two categories of vitamins needed in the human body. The first are water-soluble vitamins, like B and C. The second category is fat-soluble vitamins, such as vitamins A, D, E, and K. Water-soluble vitamins are absorbed by the intestine. Once the intestine absorbs them, the circulatory system carries them to certain tissues. Fat-soluble vitamins are also absorbed by the intestine, and the lymph system carries the vitamins to the various parts of the body. These vitamins are responsible for maintaining the structure of the cell membranes. (6) Don t think that you can have as many vitamins as you want. If too many vitamins are taken into the body, the vitamin levels in the body become toxic. Since the body can t produce the essential amounts of vitamins, there must be a certain requirement of intake of vitamins and vitamin supplements. These requirements are known as the recommended daily allowance, or RDA. If these requirements aren t met, you can become a very unhealthy person. The food and Nutrition Board of the National Academy of Science/National Research Council in the United States establishes these RDA s. For different worldwide population groups two agencies of the United Nation, the Food and Agriculture Organization and the World Health Organization have developed RDA s. It is wise to follow the RDA. Without correct interpretation of the RDA, a person could take too many or take too few vitamins. This proves that vitamins can be beneficial of harmful depending on the usage.