Bio 200: Human Nutrition Introduction

1. Bio 200: Human NutritionIntroduction Lecture 1 01/05/2012

2. Objectives and Contents • Objective: To give an overview of some of the concepts we will be looking at this quarter • Contents: • Nutrition: What is it and it’s impact • Anatomy and Physiology • Essential and non-essential nutrients • Energy balance • The “SAD” diet: an assessment

3. What is Nutrition? • The science and study of food on the health and disease of an organism • This includes how the organism ingests, digests, absorbs transports and excretes food • Studies the relationship between food and nutrients

4. Difference between food and nutrients • Food – provides the energy and materials needed to build and maintain all cells and tissues within the body • Nutrients • One specific biological function must be identified • Lack of nutrient results in decline in certain biological function • Replacing the nutrient before permanent damage occurs restores normal biological function

5. Why is nutrition important? • In America, poor nutrition and related disorders can account for two-thirds of all deaths • According to US government surveys, poor diet and lack of exercise add up to ~350,000 fatal cases of CV disease, cancer and diabetes • Obesity is considered to be second leading cause of preventable death in America

6. Anatomy and Physiology • The body is composed of trillions of cells • Cells of the same type are grouped together to form tissues • One tissue or groups of tissues with similar function are grouped together to form organs • Multiple organs involved in similar processes form organ systems • All of the organ systems form the organism

8. There are 6 classes of nutrients • Carbohydrates • Lipids • Proteins • Vitamins • Minerals • Water

9. Carbohydrates • Composed primarily of carbon, oxygen and hydrogen. • Major energy source for the body; 4 kcal/gram • Hydrophilic • Exist as simple sugars and complex carbohydrates • Monosaccharides: single sugar molecules, i.e: glucose • Disaccharide: two monosaccharides joined together, i.e: table sugar is fructose and glucose • Polysaccharide: long strands of monosaccharides strung together (aka. complex carbohydrates), i.e: starch is made up of long strands of glucose molecules

10. Glucose: an example Glucose as a Disaccharide Sucrose: (table sugar) consists of glucose and fructose Glucose as a Monosaccharide Glucose as a polysaccharide: Starch molecule consisting of multiple glucose molecules Pictures courtesy of Wikipedia

11. Lipids: Fats and Oils • Similar to carbohydrates, composed of mainly carbon, hydrogen and oxygen. Much less oxygen however • Have high energy density; 9 kcal/gram • Hydrophobic • Triglyceride is primary form in the body and food • Exist in two main groups • Saturated fatty acids: all carbons are single bonds; solid and room temp • Unsaturated fatty acids: contain one or more double bond; liquid at room temp

12. Saturated vs. Unsaturated Fat Courtesy of Wikipedia

13. Proteins • Composed of carbon, oxygen, hydrogen, and nitrogen • Main structural and functional material in the body • Can also be used for energy however only done under very certain circumstances – 4kcal/gram • Amino acids are bonded together to form proteins

14. Proteins Courtesy of Proteopedia

15. Vitamins • Varying complexity in chemical structure • Composed of carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur, and other elements • Provide no caloric energy • Main function is to enable chemical reactions • 13 divided into two groups • Fat-soluble • Water-soluble

16. Vitamins

17. Minerals • Inorganic compounds • Broken down into two main categories • Major minerals; daily recommended intake > 100mg • Trace minerals; <100mg Daily recommended intake • Minerals that conduct electricity when dissolved in water are also termed elctrolytes

18. Minerals

19. Water • Comprises ~60% of the human body • Acts as a solvent and lubricant • Transports waste • Average intake: ~3L for men and 2.2L for women • Primary sources other than the tap: Fruit and vegetables

20. Non-essential Nutrients: Phytochemicals • Plant components that provide significant health benefits but not shown to be “essential” • Usually found in whole foods • Include things like Carotenoids, Capsaicin, and Flavanoids • Currently a hot topic in research – clinical trials are ongoing for a number of phytochemicals that are thought to beneficial for cancer • The drug Taxol was a phytochemical isolated from the Chinese Yew Tree.

21. Metabolism & Energy Balance • Metabolism: The sum of all chemical reactions within the body • Catabolism-the breakdown of food and organic compounds to provide energy; ie: glucose into ATP • Anabolism-Using energy to build structures and components; ie: making proteins or cell membrane

22. Metabolism & Energy Balance • Energy in food is measured in calories • The energy needed to raise the temperature of 1g of water by 1oC. • Food calories are reported as Calories • Calories = 1000 calories = 1 kcal • Average human needs ~ 2000 calories/day • The problem is when “calories in” > metabolism

23. The Standard American Diet“SAD” • AKA: Western pattern diet • Typically consists of: • High amounts of red meat • High in saturated fats • Refined grains • Refined sugars • Low fiber • ~25% of Americans eat fast food every day • Average daily sugar intake = 22.2 tsp which is twice what is recommended

24. VisualEconomics.com

25. Final Thoughts • Hopefully by understanding the physiological requirements of the body you will be able to understand the nutritional requirements and food choices that you make everyday.