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Micronutrients
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
The phenomenon caused by vitamin deficiency in the body is called avitaminosis, and is easily cured by vitamin supply through food or supplements. In contrast, an excess of vitamins in human body, called hypervitaminosis, is toxic for the organism and can also cause ailments. It would be interesting to emphasize the difference and the similarity between vitamin and vitamer. Essentially all vitamins exist with multiple nutritionally active chemical species, often called vitamers (34). Vitamer is a member of vitamin. The term vitamin is generally designed for natural compounds found in nature (plants, animals), while different derivatives, artificial synthetic compounds or chemical names of the vitamin are called vitamer. For example, vitamin D has several vitamers which are all fat-soluble, including vitamin D2 or ergocalciferol found in mushrooms, vitamin D3 or cholecalciferol present in the human or animal body, three other vitamers rarely occuring in nature, and four synthetic analogs. Among 13 essential vitamins, there are only three vitamins endowed with antioxidant properties: vitamins A, C, and E. Some vitamins act specifically as coenzymes. The 13 vitamins will be described as follows.
Experimental Stomatology
Published in Samuel Dreizen, Barnet M. Levy, Handbook of Experimental Stomatology, 2020
Samuel Dreizen, Barnet M. Levy
All volunteers were in good condition and free from signs and symptoms of avitaminosis when the experiment began. During the 3rd and 4th week, they developed a fine, scaly, nonpruritic dermatitis that disappeared spontaneously. During the 7th and 8th weeks all showed a striking grayish pallor of the skin out of proportion to the blood picture interpreted as evidence of peripheral vasoconstriction. During the same period, the three white subjects showed definite atrophy of the lingual papillae; patchy and productive of a “geographic” tongue in the first, generalized in the second, and confined to the lateral third of the dorsum in the third. The black subject showed no changes in the tongue until the 14th week when a rather rapid denudation of the lingual papillae began. In each, the tongue remained pale throughout without any of the capillary engorgement characteristic of pellagra or ariboflavinosis. Other evidence of biotin deficiency included anorexia, nausea, vomiting, mental depression, muscle pains, paresthesias, and precordial discomfort. All signs and symptoms cleared rapidly following parenteral administration of a concentrate representing 150 to 200 μg biotin per day.
General Survey of Geomedicine
Published in Jul Låg, Geomedicine, 2017
The geographical distribution of diseases which are caused by deficiency of vitamins (avitaminosis), shows instructive geomedical examples. Often the natural factors have been decisive, but on some occasions man’s pretreatment of food and feed has had unfortunate results.
Retinopathy of prematurity in Africa: a systematic review
Published in Ophthalmic Epidemiology, 2019
Daniel Wang, Roseline Duke, Rv Paul Chan, J. Peter Campbell
ROP is a disease that did not exist 100 years ago. It emerged as health systems improve and neonatal mortality reduces. In LMIC, accurate estimates of the incidence of ROP in preterm infants are often lacking, and this is particularly true in Africa. With an estimated population more than a billion, Africa is the world’s second most populous continent after Asia.6 More than 60% of the world’s pre-term births occur in South Asia and Sub-Saharan Africa (SSA).7 Nigeria, the most populous country in SSA has the 3rd highest rate of prematurity in the world.7 A decade ago, ROP was not a leading cause of blindness in SSA, where diseases such as avitaminosis and measles are the primary contributors of preventable blindness, however this is changing.8,9 As a result, ROP has been largely neglected by several blindness prevention programs in Africa.6