chem_note5

chem_note5 - Nutrition Physical performance Nutrition to...

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137 Sport Nutrition Dr. A P L Tong Nutrition Physical performance 138 Macro Macronutrients (few grams daily) carbohydrate lipid protein water • (as biological fuels) provide energy to maintain body functions (during rest & all forms of activities) • maintain the organism’s structural and functional integrity Nutrition • is often defined as the total of processes of ingestion, digestion, absorption, and metabolism of food and the subsequent assimilation of nutrient materials into the tissues. • 6 categories: carbohydrates, lipids, proteins, vitamins, minerals and water Food Micro Micronutrients ( <1 g per day) vitamins minerals trace elements (1) Promotion of growth & development (protein) (2) Provision of energy (carbohydrate & fat) (3) Regulation of metabolism (vit, minerals & protein) Nutrients to take in for digestion 139 photosynthesis Food respiration Energy • all nutrients except water and minerals contain carbon (organic) 140 Carbohydrates Carbohydrates • carbon + water, general formula: [CH 2 O] n all living cells contain carbohydrates main source: plants Glucose – the most typical sugar (6-carbon), simple sugar, also called dextrose or blood sugar Fructose (fruit sugar) and galactose , two other simple sugars but with slight different structures to glucose (they have uniquely different biochemical characteristics). Absorbed in the small intestine where it can be directly used by cells for energy stored as glycogen in muscles or liver for later use converted to fat and stored for energy The sweetest of the simple sugars 141 Kinds & Sources • 4 categories: monosaccharides, disaccharides, oligosaccharides, and polysaccharides • number of simple sugars linked together in a molecule determines each type Glucose, fructose and galactose – monosaccharides lactose (milk sugar), maltose (found in beer, cereals and germinating seeds), sucrose – disaccharides araban, xylan – oligosaccharides (3-9) cellulose, glycogen, starch (amylose and amylopectin) polysaccharides (10 – thousands) Carbohydrates Glucose + galatose Glucose x 2 Glucose + fructose, sucrose is the most common dietary disaccharide Source: seed legumes [CH 2 O] n 142 Sucrose = glucose + fructose • the most common dietary disaccharide , ~25% of the total caloric intake in the US • occurs naturally in most food containing carbohydrates e.g. cane sugar, brown sugar, maple syrup and honey Carbohydrates
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143 Plant polysaccharides - Starch and Fibre Starch – serves as the storage form of carbohydrate in plants – plentiful in seeds, corn and various grains that make bread, cereal, spaghetti, and pastries, also found in peas, beans, potatoes and roots –twoforms: amylose , a long straight chain of glucose units twisted into a helix, amylopectin , a highly branched monosaccharide linkage (is more easily digested due to its larger surface area) Carbohydrates polymers of glucose sticky e.g.) Glutinous rice (high % of amylopectin) 144 Fibre – includes cellulose, cannot be digested – exists exclusively in plants
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chem_note5 - Nutrition Physical performance Nutrition to...

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