VITAMINS
The term vitamin has been applied to a number of complex substances known to exist in certain foods. An adequate supply of these vitamins is essential if we are to maintain good health. Lack of such a supply leads to so-called “deficiency” diseases such as pellagra, rickets, and beri-beri. Pellagra can be described as a chronic disease caused by niacin deficiency, while a lack of vitamin D and a lack of thiamine (B1) are the causes of rickets and beri-beri respectively. The symptoms produced by lack of vitamins have been recorded since 2600 B.C. in the writings of our ancient ancestors, and long before the first vitamin was discovered, medical men were convinced that such food factors existed.
However, vitamin A was not discovered until 1915. Its role in nutrition was determined, and a start was made toward its isolation. Since that time, some 15 other vitamins have been found. At first they were known only by letters of the alphabet: B, C, D, E, and K. However, it was later discovered that these were really vitamin families with several members. Scientists have therefore discarded the vague alphabetical designations. They now know the structure of each vitamin and its chemical properties. Each one can now be called by its right name. In contrast to the past, when accurate knowledge about vitamins was still unclear, today the whole field of vitamins has been so thoroughly investigated it has attained the status of an exact science.
The chemical structure of all the vitamins is known precisely, and investigators have recently devised tests making it possible to determine the amounts of certain vitamins which are contained in various body tissues. One of the more interesting discoveries reveals that vitamins are closely related to the hormones, those complex glandular secretions which govern many functions of the body. Along with this has come the realization that in the case of one vitamin, at least, an overdose may be just as harmful or dangerous as a deficiency.[EyA1]
The term vitamin has been applied to a number of complex substances known to exist in certain foods. An adequate supply of these vitamins is essential if we are to maintain good health. Lack of such a supply leads to so-called “deficiency” diseases such as pellagra, rickets, and beri-beri. Pellagra can be described as a chronic disease caused by niacin deficiency, while a lack of vitamin D and a lack of thiamine (B1) are the causes of rickets and beri-beri respectively. The symptoms produced by lack of vitamins have been recorded since 2600 B.C. in the writings of our ancient ancestors, and long before the first vitamin was discovered, medical men were convinced that such food factors existed.
However, vitamin A was not discovered until 1915. Its role in nutrition was determined, and a start was made toward its isolation. Since that time, some 15 other vitamins have been found. At first they were known only by letters of the alphabet: B, C, D, E, and K. However, it was later discovered that these were really vitamin families with several members. Scientists have therefore discarded the vague alphabetical designations. They now know the structure of each vitamin and its chemical properties. Each one can now be called by its right name. In contrast to the past, when accurate knowledge about vitamins was still unclear, today the whole field of vitamins has been so thoroughly investigated it has attained the status of an exact science.
The chemical structure of all the vitamins is known precisely, and investigators have recently devised tests making it possible to determine the amounts of certain vitamins which are contained in various body tissues. One of the more interesting discoveries reveals that vitamins are closely related to the hormones, those complex glandular secretions which govern many functions of the body. Along with this has come the realization that in the case of one vitamin, at least, an overdose may be just as harmful or dangerous as a deficiency.[EyA1]
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