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Unformatted text preview: Lecture 2: Food Choices and Nutrient Needs 1/25/10 Outline Definitions: Epidemiology Human studies cohort studies Laboratory studies animals, cells Sources Definitions • Diet: foods we eat • Calorie: o Physics: calorie = energy required to raise temp of 1 gram water 1 C o Nutrition: Kcal 1000 calories • Metric Conversions: o Fluid: 1 Liter = 1.06 quarts o Weight: 1 Kg = 2.2 lb Estimating Energy of Food using Bomb Calorimeter • Food gets heated (completely combusted) and a thermometer measures the rise in temperature of the surrounding water • Imp. Note: the bomb calorimeter burns food completely (max energy) but our real digestion system does not use all available calories Nutrients • Water—vital solvent allowing metabolism (cannot last without 7 days) • Macronutrients—provides energy o Carbs— 4 Kcal/gm, main source of energy containing Carbon, H, O o Lipids (fats)— 9 Kcal/gm, main energy and other nutrients (fatty acids). Diverse compounds such as cholesterol contains C, H, O N, P o Protein— 4 Kcal/gm, supports tissue growth, repair & maintenance, provides secondary sources of energy, contains C, H, O, Nitrogen, P o Caloric content of food used in calculation is more accurate than bomb calorimeter • Micronutrients—regulates metabolism o Vitamins (part of enzymes driving metabolic reactions), minerals Phytochemicals • “Phyto” = plants • Naturally occurring plant chemicals pigments, antioxidants, anti-cancer agents o Eg: soy, garlic, onions, tea, coffee, broccoli, barley, herbals...
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This note was uploaded on 11/02/2011 for the course NST 10 taught by Professor Amy during the Spring '08 term at Berkeley.
- Spring '08