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Food Choices: Nutrients and Nourishment BIOL 103 Chapter 1
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What is Nutrition? The science of foods (e.g. nutrients and other substances), including the relationships to health and disease; processes within the body (ingestion, digestion, absorption, transport, storage, functions, and disposal of end products); and the social, economic, cultural and their components, and psychological implications of eating.
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Factors that Influence Food Choices 1.Sensory 2.Cognitive 3.Genetics 4.Environmental 5.Health status
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Why do we eat the way we do? Sensory 1.Flavor/Taste 2.Texture 3.Appearance
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Why do we eat the way we do? Cognitive 1.Learned food habits/food reward 2.Social factors 3.Comfort/discomfort foods Behavioral motives 4.Advertising 5.Nutrition and health beliefs
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Why do we eat the way we do? Environment 1.Economics 1.Lifestyle 1.Availability 1.Cultural Influences 1.Religion
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The American Diet “Meats and potatoes” Americans age 2 and older consume, on average, 2157 calories (based on 2000 calories diet) How healthful is the “American” diet? Too little: fruits, dairy, vegetables, whole grain foods Too much: saturated fat, sodium, and sugar
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Nutrients Definition: Any substance that provides nourishment essential for growth and the maintenance of life. Essential vs. Non-essential nutrient – Essential nutrient: ______________________ – Non-essential: _________________________ How to determine if it is an nutrient?
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The six classes of nutrients (Problem Set#1, Q2) 1.Carbohydrates 2.Proteins 3.Lipids (fat) 4.Vitamins 5.Minerals 6.Water Macronutrients vs. Micronutrients
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General Functions of Nutrients (what do they do in our body) 1.Provide ____________ 2.Regulate ____________ processes 3.Build ______________ body structures
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What does Organic mean? Organic or Inorganic? – What does it mean if food is organic, in science?
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Carbohydrates Carbohydrates: “hydrate of carbon” – Made of sugar molecules Function: – ________________ for cells and tissues Dietary sources: starches and sugars found in grains, vegetables, legumes (dry beans and peas), fruits, dairy products
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Lipids Lipids (fats, oils, cholesterol, phospholipids) – Made of: ______________ ______________________ Functions: 1.Energy storage as triglycerides 2.Carries fat-soluble vitamins 3.Provides structure for body cells Food sources: fats, oils, meat, dairy, some plants (avocado, coconut)
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Proteins Made of: ____________ Functions: 1.Energy source 2.Structure for cells/tissues/body structures 3.Regulation of body processes Food sources: meats, dairy products, grains, legumes, vegetables.
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Vitamins Made of: carbon, hydrogen, and any one or combo of the following (N, O, P, S, or other elements) Functions: 1.helps regulate body processes 2.help extract energy from carbs, fat, and proteins Food sources: meats, vegetables, grains, dairy, fats
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Fat vs. Water-Soluble Vitamins Fat Soluble Vitamins – Stored in larger quantities Water Soluble Vitamins
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Minerals Inorganic substances Functions: 1.Structure 2.Regulation Food sources: all food groups
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Dietary Minerals – Macrominerals: Na, Cl, K, Ca, P, Mg – Microminerals or “trace minerals”: Fe, Zn, Cu, Mn, Mo, Se, I, Fl
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Water Most important nutrient Functions: 1.Temperature control 2.Lubrication of joints 3.Transportation of nutrients and wastes Food sources: beverages, foods like fruits and vegetables.
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Macronutrients
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Macronutrients: From Food to Fuel
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Energy in Food We eat nutrients so that we can gain energy – Energy: capacity to do work – Q: Which nutrients contain sources of potential energy? Kcal vs. Calories How do we measure energy in Nutrition? – Kilocalories (kcal) 1000 calories = 1 kilocalorie 1 kcal: the amount of energy/heat needed to raise the temperature of 1 kilogram (kg) of water by 1 degree Celsius.
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Energy in Food Use calorie as a general term for energy and kilocalorie as a specific measurement or unit of that energy.
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Problem Set #1, Q3 A) Jeff is eating a snack with 20g of carbohydrates, 5 grams of proteins, and 3 grams of fat. What is the total amount of available energy (in kcal) in his snack? (Note: you will need to show your work for full credit in an exam).
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Problem Set #1, Q3 B) Determine the percentages of kilocalories of carbohydrate, protein, and fat in Jeff’s snack.
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Many of the leading causes of death can be avoided by good diet and exercise
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More than 2/3 of U.S. Adults are overweight/obese
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Diet and Health Healthy: “a state of complete physical, mental, and social well-being AND not merely the absence of disease or infirmity.” (WHO) Disease – Acute: ____________________________ Examples: – Chronic: __________________________ Examples:
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Diet and Health Factors that influence Obesity: 1.Behavior 1.Calorie imbalance 2.Sedentary lifestyle 2.Environment Barriers to or opportunities for an active lifestyle 3.Genetics Role of heredity
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Diet and Health Physical Activity – Role in long-term weight management At least ____ mins/day of moderate activity – Weight-management At least ____ mins/day of moderate activity – What is moderate activity?
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Common Study Designs used in Nutrition Research (PS#1, Q 4 and 5) 1.Cell culture studies: effect of nutrients on cells 1.Animal Studies: effect of nutrients on animals 1.Epidemiological studies: study of disease/death rates in population groups 1.Case Control Studies: disease vs. those without disease 1.Clinical/Intervention Trials: experimental vs. control group – Placebo-controlled
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Junk Science
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Evaluating Information on the Internet There are no rules for posting on the internet Consider the source Keep in mind the scientific method Be on the lookout for “junk science” – May distort facts through omission of details
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