Chapter 7 Definition and Classification of Vitamins Vitamins organic compounds that are vital to life and indispensable to body functions but are needed only in minute amounts non caloric essential nutrients Precursors provitamins compounds that can be converted into active vitamins Beta carotene an orange pigment with antioxidant activity a vitamin A precursor made by plants and stored in human fat tissue Retinol one of the active forms of vitamin A made from beta carotene in animal and human bodies an antioxidant nutrient Retina the layer of light sensitive nerve cells lining the back of the inside of the eye Cornea the hard transparent membrane covering the outside of the eye Rhodopsin the light sensitive pigment of the cells in the retina it contains vitamin A Night blindness slow recovery of vision alter exposure to flashes of bright light at night an early symptom of vitamin A deficiency Keratin the normal protein of hair and nails Keratinization accumulation of keratin in a tissue a sign of vitamin A deficiency Xerosis drying of the corneal a symptom of vitamin A deficiency Xerophthalmia progressive hardening of the cornea of the eye in advanced vitamin A deficiency that can lead to blindness Epithelial Tissue the layers of the body that serve as selective barriers to environmental factors ex cornea skin lining of digestive tract Cell differentiation the process by which immature cells are stimulated to mature and gain the ability to perform functions characteristic of their cell type Carotenoid a member of a group of pigments in foods that range in color from light yellow to reddish orange and are chemical relatives of beta carotene Many have a degree of vitamin A activity in the body Macular degeneration a common progressive loss of function of the part of the retina that is most crucial to focused vision often leading to blindness Dietary antioxidants compounds typically found in plant foods that significantly decrease the adverse effects of oxidation on living tissues Major antioxidant vitamins are E C and beta carotene Retinol activity equivalents RAE a new measure of vitamin A activity of beta carotene and other vitamin A precursors that reflects the amount of retinol that the body will derive from a food containing vitamin A precursor compounds International Units IU a measure of fat soluble vitamin activity sometimes used in food composition tables and on supplement labels Rickets the vitamin D deficiency disease in children characterized by abnormal growth of bone and manifested in bowed legs or knock knees outward bowed chest and knobs on the ribs Osteomalacia the adult expression of vitamin D deficiency disease characterized by an overabundance of unmineralized bone protein Symptoms include bending of the spine and bowing of the legs Osteoporosis a weakening of bone mineral structures that occurs commonly with advancing age Tocopherol a kind of alcohol The active form of vitamin E is alphatocopherol Free radicals atoms or molecules with one or more unpaired electrons that make the atom or molecule unstable and highly reactive Erythrocyte hemolysis rupture of the red blood cells caused by vitamin E deficiency The anemia produced by the condition is hemolytic anemia Jaundice yellowing of the skin due to spillover of the bile pigment bilirubin from the liver into the general circulation Scurvy the vitamin C deficiency disease Abscorbic acid one of the active forms of vitamin C Collagen the chief protein of most connective tissues including scars ligaments and tendons and the underlying matrix on which bones and teeth are built Prooxidant a compound that triggers reactions involving oxygen Coenzyme a small molecule that works with an enzyme to promote the enzymes activity Many have B vitamins as part of their structure Thiamin a B vitamin involved in the body s use of fuels Beriberi the thiamin deficiency disease characterized by loss of sensation in the hands and feet muscular weakness advancing paralysis and abnormal heart action Riboflavin a B vitamin active in the body s energy releasing mechanisms Niacin a B vitamin needed in energy metabolism Niacin can be eaten preformed or can be made in the body from tryptophan one of the amino acids Other forms are nicotinic acid niacinamide and nicotinamide Pellagra the niacin deficiency disease Symptoms include the 4 D s diarrhea dermatitis dementia and death Niacin equivalents NE the amount of niacin present in food including the niacin that can theoretically be made from its precursor tryptophan that is present in the food Folate a B vitamin that acts as part of a coenzyme important in the manufacture of new cells The form added to foods and supplements is folic acid Neural tube defects NTD abnormalities of the brain and spinal cord apparent at birth and believed to be related to a woman s folate intake before and during pregnancy Dietary folate equivalent DFE a unit of measure expressing the amount of folate available to the body from naturally occurring sources The difference in absorption between less absorbable food folate and highly absorbable synthetic folate added to enriched foods and found in supplements Vitamin B12 a B vitamin that helps to convert folate to its active form and also helps maintain the sheath around nerve cells Intrinsic factor a factor found inside a system The intrinsic factor necessary to prevent pernicious anemia is now known to be a compound that helps in the absorption of vitamin B12 Pernicious anemia a vitamin b12 deficiency disease caused by lack of intrinsic factor and characterized by large immature red blood cells and damage to the nervous system Vitamin B6 a B vitamin needed in protein metabolism pyridoxine pyridoxal pyridoxamine Serotonin a neurotransmitter important in sleep regulation appetite control and mood regulation amount other roles Synthesized in the body from the amino acid tryptophan with the help of vitamin B6 Carpal tunnel syndrome a pinched nerve at the wrist causing pain by numbness in the hand caused by repetitive motion of the wrist Biotin a B vitamin a coenzyme necessary for fat synthesis and other metabolic reactions Pantothenic acid a B vitamin Choline a nonessential nutrient used to make the phospholipid lecithin and other molecules Carnitine a nonessential nutrient that functions in cellular activities Inositol a nonessential nutrient found in cell membranes Lipoic acid a nonessential nutrient
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