Nutrition 1

• Nutrition


  Process of taking in food and converting it into energy and other vital nutrients required for life
• Nutrients


  Any substance used by an organism to survive, grow, and reproduce
• Macronutrients


  • Carbohydrates
  • Protein
  • Lipids
• Essential nutrients


  Required in minute quantities (micrograms to milligrams per day)
• Macronutrients


  Required in relatively larger amounts than other nutrients

  
• Macronutrients


  • Provide your body with energy and the components it needs to maintain its structure and functions
  • Considered essential nutrients
  • Needed in relatively larger amounts than other nutrients
  • Required in large quantities: 10 grams plus per day

  
• Energy requirements


  Energy is required in the body for metabolic processes, physiological functions, muscular activity, heat production, growth and synthesis of new tissues
• Energy sources


  Carbohydrates, proteins, fats and, to a lesser degree, alcohol
• Average amount of energy released ranges from approximately 16.7 kJ/g for carbohydrates or protein to 29.3 kJ/g for alcohol and 37.7 kJ/g for fats

  
• Estimated Energy Requirement (EER)

  • The Estimated Energy Requirement for Maintenance (EERM, or actual energy requirement) is the dietary energy intake that is predicted to maintain energy balance (plus extra needs for pregnancy, lactation and growth) in healthy individuals or groups of individuals at current levels of body size and level of physical activity
  • The Desirable Estimated Energy Requirement (DEER, or energy reference value) is the dietary energy intake that is predicted to maintain energy balance (plus extra needs for pregnancy, lactation and growth) in healthy individuals or groups of individuals of a defined gender, age, weight, height and level of physical activity consistent with good health and/or development

  
• Personal energy requirement


  1. Basic energy requirement = 1.3 calories x hours x kg body weight

  2. Extra energy requirement = 8.5 calories x hours x kg body weight
• Functions of carbohydrates


  • Energy production
  • Energy storage
  • Building macromolecules
  • Sparing protein
  • Lipid metabolism
• Simple carbohydrates


  Monosaccharides and disaccharides
• Complex carbohydrates


  Polysaccharides such as starch
• Glucose


  Simple sugar with the molecular formula C₆H₁₂O₆, the most abundant monosaccharide, the principal fuel used by the brain and nervous system and by red blood cells

  
• Fructose


  Absorbed almost entirely by the liver as most cells lack its transporter glut-5, does not stimulate insulin release, poorly absorbed from gastrointestinal tract, does not suppress grehlin, predominantly absorbed passively from the intestinal lumen via the hexose transporter SLC2A5, also known as GLUT5, which has high affinity for fructose (Km = 6 mM), rapidly phosphorylated by ketohexokinase (KHK, also known as fructokinase) to generate fructose-1-phosphate (F1P), F1P is metabolized to dihydroxyacetone phosphate (DHAP) and glyceraldehyde 3-phosphate (G3P), which enter the glycolytic/gluconeogenic metabolite pools
• Glycemic index (GI)


  A measure of the potency of a test food at raising blood glucose level compared to potency of glucose, ranks the glycemic potency of foods, calculated as the incremental area under the curve (iAUC) for blood glucose after consumption of a test food divided by the iAUC of a reference food containing the same amount of carbohydrate

  
• Glycemic load


  Refers to the amount of carbohydrate consumed multiplied by the rate at which the carbohydrate is metabolized and enters the bloodstream (glycemic index), takes size of portions into account, indicates how much a given serving of a test food will raise blood glucose, calculated as (GI / 100) x g of carbohydrate in serving

  
• Functions of proteins


  • Growth and maintenance
  • Causes biochemical reactions
  • Acts as a messenger
  • Provides structure
  • Maintains proper pH
  • Balances fluids
  • Transports and stores nutrients
  • Provides energy
• Essential amino acids


  • List of essential amino acids
• Essential fatty acids


  • List of essential fatty acids