NUTR 202 Ch 7 - Flashcards
20 Cards in this Set
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Vitamin
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organic essential nutrients required in tiny amounts
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*Bloavallavillty
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rate and extent to which nutrient is absorbed and used
Vitamins can be damaged by light, oxygen, heat and washing.
Refrigeration slows deterioration as does cooking minimum time in minimum water. Preparation method can be important.
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Precursor
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substance that preceeds others – some precursors can be converted to an active vitamin inside the body
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Fortification
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Adding nutrients to foods to prevent deficiencies or promote health
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Enrichment
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adding nutrients to restore those lost in processing
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Vitamin Functions: Coenzymes, Antioxidants
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Coenzymes
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that increase activity of enzymes – B vitamins are especially important in extracting energy in Krebs cycle
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Antioxidants
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prevent cellular damage by preventing free radical formation
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Water-Soluble Vitamins
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carried freely in watery blood and excesses are excreted by kidneys, thus are not very toxic, but excess can cause problems. These are carried in the blood stream to the liver
Vitamins come from a varied food supply – especially fruits & vegetables.
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Toxicity is dose related response
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more is not always better – fat-soluble vitamins and minerals can be toxic at high doses with no good excretion route
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Fat soluble vitamins
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carried initially in chylomicrons in the lymph system till protein carriers are attached.
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Water Soluble Vitamins
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include 8 B vitamins and Vitamin C: B vitamins serve as coenzymes in energy metabolism (TCA cycle and Electron Transport Chain) so deficlencles lead to a lack of energy
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Thiamine
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coenzyme in energy release from nutrients - nerves and muscle & in synthesis of neurotransmitters for nerve cells
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Beri-Beri
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Deficiency disease discovered with advent of rice polishing
Also involved in Warnike-Korsakoff syndrome in alcoholics when alcohol decreases absorption of thiamine
No reported toxicity
Source - pork, whole grains, legumes - Leaches into cooking water
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Riboflavin (Coenzyme)
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coenzyme - energy release from nutrients – all body cells
Deficiency – inflammation of membranes especially eyes and mouth
Source – milk, whole grains, green vegetables
UV light destroys but not heat – pasteurized milk is packaged in opaque cartons to protect riboflavin
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Niacin
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coenzyme in energy transfer - lowers cholesterol, functions in glucose and fatty acid metabolism
Body can make it from tryptophan
Deficiency – pellagra (4 D’s – diarrhea, dermatitis, dementia, death) was common in South till WW 1due to high corn diets deficient in niacin
Toxicity – nia…
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Biotin
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coenzyme that carries CO2 in TCA cycle
Deficiency – rare can be induced by raw egg whites which have Avidin – causes nausea, hair loss, lethargy
Source – egg yolks & widespread in foods
No reported toxicity
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Panothenic acid
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part of coenzyme A - crossroads compound in metabolic pathways
Deficiency – rare – involves general failure all body systems
Sources - widespread in meats, cereals, vegetables
Relatively nontoxic
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Vitamin B6
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coenzyme in amino acid metabolism, hemoglobin and DNA synthesis – works with more than 100 enzyme systems
Deficiency – depression & confusion – hastened by high protein diet making needs more
Toxicity – only with supplements – causes neurological damage
Source – meat, fish, poultry, ve…
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Folate (folic acid)
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Nutrition 202 Exam 1 Flashcards