1 / 21

Introduction to the Science of Nutrition

Introduction to the Science of Nutrition. NS 332 9/4/09. Nutrition: the process by which a living organism assimilates food and uses it for growth and maintenance of tissues. Nutrients- components of food: Provide energy Provide structural materials

felice
Download Presentation

Introduction to the Science of Nutrition

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Introduction to the Science of Nutrition NS 332 9/4/09

  2. Nutrition: the process by which a living organism assimilates food and uses it for growth and maintenance of tissues Nutrients- components of food: • Provide energy • Provide structural materials • Provide regulatory agents that support cell growth, maintenance, and repair of tissues • May reduce the risk of certain diseases

  3. Definitions - Homeostasis • Food • Diet • Organic (vitamins) • Inorganic (minerals) • Essential nutrient (3 criteria) • Phytochemical: non-essential, but may optimize nutritional status

  4. An Abbreviated History of Nutrition • 1747: Dr. Lind discovered that limes prevented scurvy • 1770: Levoisier documented that food and oxygen in the body produces in heat and water • 1897: Eijkman discovered that brown rice as opposed to white rice prevented Beri-Beri • 1912: McCollum discovered vitamin A

  5. Current Nutrition • Determine: • Optimal levels of nutrients that lead to optimal health • The role of phytochemicals- non essential but may lead to greater health • Optimal nutrition for individuals

  6. Classes of Nutrients • Macronutrients - Carbohydrate - Lipid - Protein - Water • Micronutrients • Vitamins • Minerals

  7. Classes of Nutrients: Carbohydrates - Main source of energy - Fruits, vegetables, grains - Composed of carbon (C), hydrogen (H), and oxygen (0) - Sugars, starches, and fiber

  8. Classes of Nutrients: Lipids - Energy source, component of cell walls - Oils, fats, nuts, fatty fish, avocado - C, H, O, sometimes phosphorous (P) and nitrogen (N) - Saturated, unsaturated, essential, and trans fats

  9. Classes of Nutrients: Proteins - Main structural material in the body and nitrogen source - Meat, poultry, fish, soy based products, dairy, legumes, grains - C,H,O,N,S - Composed of amino acids - Complete vs incomplete

  10. Classes of Nutrients: Water - Essential for all life • Functions as a solvent, a lubricant, and a medium for transporting nutrients into cells • Human body is 60% water

  11. Classes of Nutrients Vitamins - Organic compounds (13 known essential) - Necessary for specific biochemical reactions in cells - Water or fat soluble Minerals - Inorganic elements (16 known essential) - Key roles in the nervous and skeletal system as well as necessary for biochemical reactions in cells - Major and trace

  12. Nutrient Composition of the Body versus Food

  13. Energy: the Capacity to do Work • Without energy, we couldn’t move or breathe • Food is a form of chemical energy measured in calories • Calorie is a unit of heat energy: • 1 kilocalorie = 1000 calories • 1 kcal = the amount of energy necessary to increase the temperature of 1 kg of water 1°C (a relatively small amt of heat) • Food is more accurately expressed in kcal • Food labels use ‘calories’ but they really mean kcal

  14. Energy in Biological Systems: ATP • Without energy we couldn’t move or breathe • Adenosine triphosphate • Energy from food is captured as ATP through metabolism • ATP drives any biological reaction that requires energy

  15. How do we know how much energy (calories) is in the food we eat? • 4-9-4 rule: • Carbohydrate = 4 kcal/gram • Fat = 9 kcal/gram • Protein = 4 kcal/gram • 1 medium banana • carbs 30g x 4 kcal/g = 120 kcal • fat 0.5g x 9 kcal/g = 5 kcal • protein 1.0g x 4 kcal/g = 4 kcal • Total = 129 kcal

  16. Daily intake of Macronutrients Carbs: 300 g x 4 kcal/g = 1,200 kcal (62% total) Fat: 50 g x 9 kcal/g = 450 kcal (23% total) Protein: 70g x 4kcal/g = 280 kcal (15% total) 1,930 total kcal

  17. Nutrient Density • A ratio of vitamin and mineral content of a food to its energy content 5%-- Energy-------4% 0%-- Protein------18% 0%-- Vitamin A---21% 0%-- Vitamin C---0% 0%-- Thiamine---10% 0%-- Riboflavin---44% 0%-- Niacin--------2% 0%-- Calcium------24% 0%-- Iron-----------0% 8 oz 8 oz (shown as a %RDA for adolescent females)

  18. Energy Density • A ratio of the energy content of a food (kcal) with its weight (g)

  19. Nutritional Assessment • Anthropometric measurements • Biochemical testing • Clinical Assessment • Diet history

  20. Malnutrition • Undernutrition • Biochemical lesion • Clinical lesion • Primary deficiency • Secondary deficiency

  21. Malnutrition • Overnutrition • Obesity – excess of energy • Excess of micronutrients

More Related