Understanding Nutrition and Your Diet
Chapter 5Chapter 5
NutrientsNutrients
• Nutrients = elements in food that are required for the growth, repair, and regulation of body processes1. Carbohydrates2. Fats3. Protein4. Vitamins5. Minerals6. Water7. Fiber
Energy from FoodEnergy from Food
Calorie = unit of energy1 calorie = amount of energy needed
to raise the temperature of 1 gram of water by 1 degree Celsius
In common usage, “calorie” refers to “kilocalorie” (1,000 calories)
CarbohydratesCarbohydrates
Major energy source: 4 calories/gramTypes
MonosaccharidesDisaccharidesPolysaccharides
Recommended intake: 45-65% of total calories from carbohydrates
CarbohydratesCarbohydrates
Simple sugars Average American adult consumes about
140 pounds of sweeteners each year Sugar, corn sweetener, syrup, honey Sodas, candy, bakery and processed goods
Sugar substitutes Saccharin Aspartame Sucralose, tagatose Sorbitol, xylitol Acesulfame potassium Neotame
FatsFats
Functions: Insulation, carrier of vitamins, storage of long-term energy, and satiety
Energy source: 9 calories/gram Types
SaturatedMonounsaturatedPolyunsaturatedTrans
Recommended intake: 20-35% of total calories
Types of FatsTypes of Fats
Saturated fats Solid at room temperature Primarily found in animal fats Negative effects on heart health
Monounsaturated and polyunsaturated fats Liquid at room temperature Vegetable oils Positive effects on heart health Omega-3 polyunsaturated fats found in fish are
considered especially healthful
Composition of Dietary FatsComposition of Dietary Fats
Types of Fats: Trans FatsTypes of Fats: Trans Fats
Altered form of unsaturated fat (hydrogen added)
Associated with unhealthy changes in cell membranes
Raises levels of “bad” cholesterol and lowers levels of “good” cholesterol
Found in margarine, snack foods, and some deep fried fast foodsCheck food labels
Types of Fats: CholesterolTypes of Fats: Cholesterol
White fatlike substance found in cells of animal origin
Functions: Synthesizes cell membranes; starting material in formation of hormones and bile
The liver can synthesize cholesterolExcess cholesterol in the body can
clog arteries and increase risk of cardiovascular disease
FatsFats
Low-fat does not necessarily mean low-calorie
Higher price tag Low-fat dairy and
salad dressings have less saturated fat
Simplesse, Olestra Fats cannot be
broken down and absorbed by body
Unpleasant side effects
Low-fat foods Fat substitutes
Fats: General Fats: General RecommendationsRecommendations
20-35% of total daily calories from fat Less than 10% of calories from
saturated fat Less than 300 mg/day of cholesterol Keep trans-fatty acid consumption as
low as possible Get most fats from sources of
unsaturated fats Fish Nuts Vegetable oils
ProteinProtein
Functions: Growth and maintenance of tissue, acid-base balance
Energy source: 4 calories/gramAmino acids = building blocks of
protein11 can be built by the body
Nonessential amino acids9 must be obtained from food
Essential amino acids
ProteinProtein
Complete protein sources supply all essential amino acidsAnimal foods, soybeans
Incomplete protein sources supply some but not all essential amino acidsPlant foods
Recommended intake: 10-35% of total calories
VitaminsVitamins
Organic compounds needed in small amounts for normal growth, reproduction, and maintenance of health
Serve as co-enzymes Provide no energy: 0 calories/gram Types
Water soluble B-complex vitamins and vitamin C
Fat soluble Vitamins A, D, E, K
Vitamins: Should I Take a Vitamins: Should I Take a Supplement?Supplement?
Following dietary recommendations would allow most Americans to meet their nutrient needs without supplements Many people eat too many nutrient-deficient foods
Caution with using supplementsHypervitaminosis = toxicity Megadoses of any vitamin can be harmful
Recommendations for certain groups Folic acid, vitamin B-12, vitamin D
PhytochemicalsPhytochemicals
Phytochemicals = physiologically active components of foods that may deactivate carcinogens
Many phytochemicals function as antioxidants May protect cells from damage caused by
unstable molecules (“free radicals”) Examples
Carotenoids Polyphenols Allyl sulfides
MineralsMinerals
Inorganic materials that act as structural elements and regulators of numerous body processes
Provide no energy: 0 calories/gramTypes
Macronutrients: “Major minerals” found in high amounts in the body
Micronutrients: “Trace elements” found in small amounts in the body
Water and FluidsWater and Fluids
Average adult loses about 10 cups of water per day Urination, bowel movements, breathing,
perspiration Functions: Provide medium for nutrients,
waste transport, temperature control For every pound of body weight, you need
about 0.5 ounce of fluid Sources: Beverages, fruits, vegetables
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Vitamins Minerals Water ProteinCarbohydrates
SugarsStarches
Cellulose
Fats
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Calories per gram:Calories per gram:Protein 1 Gram = 4 caloriesCarbohydrates 1 Gram = 4 caloriesFat 1 Gram = 9 calories
Generally speaking, You need to have save about 3000 Calories (kcals)In order to lose a pound of weight
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Variables which affect nutrient needs:
1. Age
2. Gender
3. Activity Level
4. Climate
5. Health
6. State of nutrition
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Trans fats reviewTrans fats review
triglyceride
FiberFiber
Cellulose-based plant material that cannot be digested
Provides no energy: 0 calories/gram Types:
Soluble (gel-forming) Insoluble (absorbs water)
Benefits Moves stool through digestive tract Lowers blood cholesterol levels Steadies blood sugar levels
Recommended: 21-38 grams/day Most American adults: 11 grams/day
Dietary Reference IntakesDietary Reference Intakes
Dietary Reference Intakes (DRIs) = recommended nutrient intakes Estimated Average Requirement (EAR) Recommended Dietary Allowance (RDA) Tolerable Upper Intake Level (UL)
Acceptable Macronutrient Distribution Range (AMDR)—percent of total daily calories
45-65% as carbohydrate20-35% as fat10-35% as protein
The Digestive System: The The Digestive System: The Absorption of NutrientsAbsorption of Nutrients
© 2009 McGraw-Hill Higher Education. All rights reserved.
© 2009 McGraw-Hill Higher Education. All rights reserved.
Tools for Planning a Tools for Planning a Healthy DietHealthy Diet
The USDA Food Guide: MyPyramid
The Dietary Guidelines for Americans
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The old food pyramidThe old food pyramid
MyPyramidMyPyramid
MyPyramidMyPyramid
Personalized approachAmounts recommended from each food
group vary based on age, gender, and activity level
Visit www.mypyramid.govBalance food intake and physical
activity
MyPyramid Food GroupsMyPyramid Food Groups
Fruits 2 cups/day for a 2,000-calorie diet Eat a variety of fruits Favor whole fruits over fruit juices
Vegetables 2 1/2 cups/day for a 2,000-calorie diet Eat a variety of vegetables
Dark green vegetables Orange vegetables Legumes Starchy vegetables Other vegetables
MyPyramid Food GroupsMyPyramid Food Groups
Milk and milk products3 cups/day for a 2,000-calorie dietFavor fat-free or low-fat productsVegans and those who are lactose
intolerant should choose other sources of calcium
MyPyramid Food GroupsMyPyramid Food Groups
Meat, poultry, fish, eggs, dry beans, and nuts5 1/2 ounce-equivalents for a 2,000-
calorie diet1 ounce equivalents:
1 ounce cooked meat, poultry, fish1 egg1/4 cup legumes or tofu1 tablespoon peanut butter1/2 ounce nuts or seeds
Choose lean and low-fat foods
MyPyramid Food GroupsMyPyramid Food Groups
Breads, cereals, rice, and pasta6 ounces/day for a 2,000-calorie diet3 or more ounces/day should be whole
grains
1 ounce equivalents:1 slice bread1 cup dry cereal1/2 cup cooked rice, pasta, cereal
MyPyramid Food GroupsMyPyramid Food Groups
Oils (vegetable oils, fish, nuts, seeds)24 grams or 6 teaspoons/day for a 2,000-
calorie diet1 teaspoon equivalents:
1 teaspoon vegetable oil or margarine1 tablespoon low-fat mayonnaise2 tablespoons light salad dressing
Discretionary calories
http://www.thecaloriecounter.com/foods/1400/14533/food.aspx
Dietary Guidelines for Dietary Guidelines for AmericansAmericans
Adequate nutrients within calorie needsConsume nutrient-dense foods within and
among the food groupsWeight management
Balance calories from foods and beverages with calories expended
Make small decreases in calorie intake to prevent gradual weight gain over time
Dietary Guidelines for Dietary Guidelines for AmericansAmericans
Physical activityRegular moderate physical activity
30 minutes/day to reduce risk of chronic disease
60 minutes/day to prevent gradual, unhealthy weight gain
60-90 minutes/day to sustain weight lossDecrease sedentary activities
Dietary Guidelines for Dietary Guidelines for AmericansAmericans
Food groups to encourage Fruits Vegetables Milk
Fats Total fat: 20-35% of total calories Saturated fat: <10% of total
calories Cholesterol: <300 mg/day Limit trans fats
Dietary Guidelines for Dietary Guidelines for AmericansAmericans
CarbohydratesChoose whole grains oftenLimit added sugars
Sodium and potassiumSodium: Consume less than 2,300 mg/day
(about 1 teaspoon of salt)Potassium: Consume potassium-rich foods
such as fruits and vegetables
Dietary Guidelines for Dietary Guidelines for AmericansAmericans
Alcoholic beveragesThose who choose to drink should do so
sensibly and in moderationUp to 1 drink/day for womenUp to 2 drinks/day for men
Food safetyTake steps to avoid microbial foodborne
illness
Vegetarian DietsVegetarian Diets
Reliance on plant sources for most of the nutrients the body needs Ovovegetarian: Includes eggs Lactovegetarian: Includes dairy Ovolactovegetarian: Includes eggs and dairy Vegan: Excludes all animal products
Requires more planning Need to maintain adequate intake of vitamin B-12,
calcium, iron, zinc, vitamin D Semivegetarian: Great reduction (but not
elimination) of meat products Pescovegetarian: Includes fish, eggs, dairy products
MyPyramid for MyPyramid for Ovolacto-Ovolacto-
vegetariansvegetarians
Nutrition and the Older AdultNutrition and the Older Adult
Older adults may find food less tasteful, harder to chew
Lower energy requirementsPsychosocial factors
Social isolationDepressionAlcohol consumption Limited transportation
Food LabelsFood Labels
Required by the FDA since 1973
New in 2006Amount of trans fatProteins derived from
major food allergen sources
Nutrition Nutrition Facts LabelFacts Label
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NuValNuVal
http://www.nuval.com/Shop/trading
Fast FoodsFast Foods
Fat density of fast foods40-70% of calories in fast foods is fatRecommended intake: 20-35% of total
daily calories from fatMost people underestimate the
calorie content in a fast food meal by as much as 500 calories
Functional FoodsFunctional Foods
Foods capable of contributing to the improvement or prevention of specific health problemsProbiotics: Living bacteria that help
prevent disease and strengthen the immune system (e.g., yogurt)
Garlic, olive oil, high-fiber foods, calcium-rich foods, antioxident-rich foods
Foods enriched with folic acid
Dietary SupplementsDietary Supplements
Products that supplement the total daily intake of nutrients in the diet
Ingested in tablet, capsule, softgel, gelcap, and liquid form
Not in themselves used as conventional foods or as the only items in a meal or diet
Must be deemed safe for human Cannot claim to cure or treat diseases
Americans spent over $19 billion on supplements (in 2005)
Food AllergiesFood Allergies
Allergy = reaction in which the immune system attacks an otherwise harmless food or ingredient Different from a food intolerance, which is
usually caused by an enzyme deficiency Common food allergens include peanuts,
milk, soy products, shellfish, and wheat Allergic reactions can develop slowly over
several exposures Symptoms range from mildly unpleasant to
life threatening
Food SafetyFood Safety
Preventing foodborne illnessSafe handling,
cooking, and storage of foods
Food SafetyFood Safety
Food irradiationUse of radiation to kill foodborne
pathogensSafe farming techniques
More humane treatment of farm animalsImproved food qualityReduced exposure to antibiotic-resistant
bacteria, prions (cause of “mad cow disease”), and chemicals
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What is Mad Cow disease?What is Mad Cow disease?
Food SafetyFood Safety
Organic foodsNo use of growth
hormone or antibioticsNot genetically
engineered or irradiatedNo use of chemical
fertilizers or sewage sludge
Diseases, pets, and weeds treated or controlled primarily with nonchemical means
Food SafetyFood Safety
Food additivesProvide color or flavorReplace sugar or fatImprove nutritional content, texture, or
shelf lifeFDA tested
Genetically modified foodsAltered to improve yields and reduce
costs
Chapter Five: Chapter Five: Understanding Nutrition and Your DietUnderstanding Nutrition and Your Diet
© 2009 McGraw-Hill Higher Education. All rights reserved.
Discussion questionsDiscussion questionsWhy does it cost more to eat healthy, but it is cheap to eat poorly?
How can we incorporate more fiber in our diet and what advantage does it serve?
How can sodium levels be exceeded and what problems do they cause
What are the advantages from getting vitamins from foods rather than supplements?
What is the advantage of so called functional foods?