Nurition Unit 10 & 11

Nurition Unit 10 & 11 - Unit 10 & 11 Vitamin...

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Vitamin Characteristics Organic Essential nutrients Required in tiny amounts to perform specific functions that promote growth, reproduction, or the Name derived from: o Vita: life o Amines: containing nitrogen (First vitamins discovered contained Nitrogen) How Vitamins Differ from CHOs, fats and proteins Structure: o Individual units Function: o Do not yield energy o Assist enzymes that release energy from macronutrients (Coenzyme) Food contents: o Measured in micrograms ( μ g) or mg Vitamin Availability from food depends on 1) Quantity provided by food 2) Bioavailability: o Factors affecting bioavailability: Previous nutrient intake and status Other foods consumed at the same time Method of food preparation Source of nutrient Precursors Precursors are: o Substances that precede others o Vitamin precursors are compounds that can be converted into active vitamins o Vitamin precursors are known as provitamins Organic Nature of Vitamins Vitamins can be destroyed by: o Prolonged heating o UV light o Oxygen Ways to reduce vitamin loss/destruction: o Refrigeration o Storage in airtight containers o o Microwave or steam in small amounts of water. Differences in Water Soluble and Fat Soluble Vitamins
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Water-Soluble Vits: B Vits and Vit C o Absorption Vascular system – Hydrophilic o Transport Travel freely o Storage Circulate freely in water-filled body parts o Excretion Kidneys detect and remove excess in urine o Toxicity Toxicity possible with supplements o Requirements Needed in frequent doses (every 1-3 days) Fat-Soluble Vits: Vit A, D, E, and K o Absorption First into lympthatic system; then into vascular system – Hydrophobic o Transport Many require protein carriers o Storage Stored in fat cells o Excretion Not readily excreted; tend to remain in fat-storage sites o Toxicity Toxicity likey with supplements o Requirements Needed in periodic doses (perhaps weeks or even months) Toxicity Currently tolerable upper levels (TULs) established for the following water- soluble vitamins: o Niacin o Vitamin B6 o Folate o Choline o Vitamin C The B Vitamins Thiamin – Vitamin B 1 o Coenzyme form TPP (thiamin pyrophosphate) o Chief function Coenzyme in energy metabolism o Food sources All nutritious foods Whole-grain Fortified, enriched, or grain products Pork o Deficiency disease
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Beriberi o Deficiency symptoms Wet beriberi Edema Enlarged heart Cardiac Failure Dry beriberi Muscle wasting “high stepping gait” o Toxicity symptoms None reported o Associated conditions Wernicke-Koraskoff syndrome Severe thiamine deficiency in alcoholics Symptoms include: o Disorientation o
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This note was uploaded on 10/06/2008 for the course NTDT 20403 taught by Professor Gorman during the Spring '07 term at TCU.

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Nurition Unit 10 & 11 - Unit 10 & 11 Vitamin...

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