Transcript ppt
What is Nutrition? •The science of food, the nutrients and the substances therein, •their action, interaction, and balance in relation to health and disease, •and the process by which the organism ingests, digests, absorbs, transports, utilizes, and excretes food substances. States of Nutritional Health Desirable Nutrition nutrients consumed support body functions and stores for times of increased need. Malnutrition –Undernutrition nutrient intake does not meet minimal needs; can lead to reduced biochemical function and serious long term effects –Overnutrition* nutrients are consumed in excess of the body needs; can lead to toxicity or obesity * biggest problem in the US due to excess of saturated fats and salt high in fiber and fluid high in fruit low in saturated and trans fats * high in whole grains little or no alcohol high in vegetables adequate in nutrients moderate in calories Nutrition and your Health Leading Cause of Death in the U.S. •4 of top 6 are nutrition-dependent Nutrition and Your Health Poor diet is a risk factor for several chronic diseases and ailments –heart disease –cancer (e.g., colon, breast) –diabetes –stroke –hypertension –Anemia (iron-deficiency) –osteoporosis –cirrhosis of the liver –fetal alcohol syndrome –stunted growth Poor diets kill 300,000 people/year from these top 3 diseases alone Nutrition, Disease, and Genetics New Research Fields: •nutritional genomics •molecular nutrition •nutrigenomics How Aware are You of your Nutritional Health? •overall population is getting fatter •probably due to an increasingly sedentary lifestyle, •poorer diets, •and a busier work schedule Why Do We Eat? We eat to get Nutrients. Nutrients are the nourishing substances we must obtain from food. These essential substances are vital for growth and maintenance from infancy to adulthood. The minimum diet for healthy growth, development, and maintenance MUST contain about 45 essential nutrients. Classes of Nutrients and Their Elements Function of Nutrients •Energy Providers •Growth and Development Providers •Body Processes Regulators Energy Providing Nutrients Food Energy is measured in calories (kilocalorie, Calorie): The amount of heat energy necessary to raise the temperature of a liter (1 kilogram) of water 1 degree Celsius. Metabolic Rate (MR): The overall rate at which nutrients are broken down to produce energy for ATP and heat Basal Metabolic Rate (bMR): The rate at which a quiet, resting, fasting body breaks down nutrients to liberate energy. The thyroid hormone is the main regulator of bMR •Energy Producing Nutrients: •Carbohydrates •Fats/Lipids •Proteins Table 1-3, p. 6 Growth and Development Nutrients Body Process Regulator Nutrients •Vitamins •Minerals •Water •Proteins (some functions) •Fiber (from carbohydrates) Why Do We Eat What We Do? Body Image The Science of Nutrition •Nutrition is true science but a young science –1897 – first vitamin identified –1940’s – first protein structure •It is a complex, interactive science •Research Design can take many forms: –Epidemiological study –Case study –Laboratory study –Intervention study Scientific Method Nutritious Diet Characteristics •Adequacy –Foods provide enough of each essential nutrient, fiber, and energy •Balance –All food groups are represented; one is not overrepresented •Calorie Control –Food provides enough energy to maintain weight •Moderation –There is no excess nor unwanted food groups •Variety –Foods differ from one day to the next Dietary Reference Intakes (DRI) Represent up-to-date optimal, and safe nutrient intakes for healthy people in the US and Canada They are based on scientific investigation DRI Committee Goals are to: 1. Set Recommended Intake Values (RDA, AI) 2. Facilitate Nutrition Research and Policy (EAR) 3. Establish Safety Guidelines (UL) 4. Prevent Chronic Diseases (AMDR) Nutrient Standards Daily Values Standards used only on food labels to enable customers to compare the nutrient values among foods They reflect the needs of an average person – someone eating 2000-2500 calories/day Are much less useful as nutrient intake goals for individuals 1992 Nutritional Requirements The New 2005 MyPyramid Process to replace the 1992 model was secret No more food hierarchies According to USDA staff: Influence of food lobbies is •Keep physically active apparent •Eat in moderation •Make personalized food choices •Eat a variety of foods in the recommended number of servings •Pursue gradual dietary improvement What’s Your Excuse? Most Often Knowledge is Key 2005 US Dietary Guidelines Fig. 1-5a, p. 16 2005 US Dietary Guidelines Fig. 1-5b, p. 16 2005 US Dietary Guidelines Fig. 1-5c, p. 16 2005 US Dietary Guidelines Fig. 1-5d, p. 16 2005 US Dietary Guidelines Fig. 1-5e, p. 16 2005 US Dietary Guidelines Fig. 1-5f, p. 16 2005 US Dietary Guidelines Fig. 1-5g, p. 16 2005 US Dietary Guidelines Fig. 1-5h, p. 16 U.S. Nutrition Objectives 2010