FC_C8_Helena C & D

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Chapter 8

NUTRITION

Nutritional Requirements: Components of a Healthy Diet  Essential nutrients = substances the body must get from food because it cannot manufacture them at all or fast enough to meet its needs  Proteins  Carbohydrates  Fats  Vitamins  Minerals  Water Chapter 8

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Energy from Food  Three classes of essential nutrients supply energy. Which ones?  Kilocalorie = a measure of energy content in

food; the amount of heat it takes to raise the temperature of 1 liter of water 1°C; commonly referred to as “calorie”

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Sources of Energy in the Diet

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Proteins—The Basis of Body Structure  Protein = a compound made of amino acids that contains carbon, hydrogen, oxygen, and nitrogen  Of twenty common amino acids in foods, nine are essential  Proteins form key parts of the body’s main structural components—muscles and bones— and of blood, enzymes, cell membranes, and

some hormones

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Fats—Essential in Small Amounts  Fats supply energy, insulate the body, support and cushion organs, absorb fatsoluble vitamins, add flavor and texture to

foods  Essential fats are key regulators of body process such as the maintenance of blood pressure and the progress of a healthy pregnancy Chapter 8

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Types and Sources of Fats  Saturated fat = a fat with no carbon-carbon double

bonds; usually solid at room temperature  Found primarily in animal foods and palm and coconut oils  Monounsaturated fat = a fat with one carbon-carbon double bond; usually liquid at room temperature  Found in certain vegetables, nuts, and vegetable oils  Polyunsaturated fat = a fat with two or more carboncarbon double bonds; usually liquid at room temperature  Found in certain vegetables, nuts, and vegetable oils and in fatty fish Chapter 8

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Fats and Health  Fats also affect triglyceride levels,

inflammation, heart rhythm, blood pressure, and cancer risk  Best choices = monounsaturated fats and polyunsaturated omega-3 fats  Limit intake of saturated and trans fats

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Fats and Health  Fats affect blood cholesterol levels  Low-density lipoprotein (LDL) = “bad”

cholesterol  High-density lipoprotein (HDL) = “good” cholesterol  Saturated and trans fats raise levels of LDL; trans fats also lower levels of HDL  Unsaturated fats lower levels of LDL

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Carbohydrates—An Ideal Source of Energy  The primary function of dietary carbohydrate is to supply energy to body cells.  Some cells, such as those in the brain, nervous

system, and blood, use only carbohydrates for fuel  During high-intensity exercise, muscles get most of their energy from carbohydrates  During digestion, carbohydrates are broken into single sugar molecules such as glucose for absorption; the liver and muscles take up glucose and store it in the form of glycogen Chapter 8

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Simple and Complex Carbohydrates  Simple carbohydrates contain one or two sugar units in each molecule  Found naturally in fruits and milk and added to many other

foods  Include sucrose, fructose, maltose, and lactose

 Complex carbohydrates consist of chains of many sugar molecules  Found in plants, especially grains, legumes, and tubers  Include starches and most types of dietary fiber

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Whole Grains  Before they are processed, all grains are whole grains consisting of an inner layer of germ, a middle layer called the endosperm, and an outer layer of bran  During processing, the germ and bran are often removed, leaving just the starchy endosperm  Refined carbohydrates usually retain all the calories of a whole grain but lose many of the nutrients Chapter 8

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Refined Carbohydrates Versus Whole Grains  Whole grains are higher than refined carbohydrates in fiber, vitamins, minerals, and other beneficial compounds  Whole grains take longer to digest  Make people feel full sooner  Cause a slower rise in glucose levels

 Choose foods that have a whole grain as the first item on the ingredient list on the food label  Whole wheat, whole rye, whole oats, oatmeal, whole-

grain corn, brown rice, popcorn, barley, etc.

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Reading a Food Label

1. Serving Size  The first place to start when you look at the Nutrition Facts label  Serving sizes are standardized to make it easier to compare 

 



similar foods; They are provided in familiar units, such as cups or pieces, followed by the metric amount, e.g., the number of grams. The size of the serving on the food package influences the number of calories and all the nutrient amounts listed on the top part of the label. Pay attention to the serving size, especially how many servings there are in the food package. Then ask yourself, "How many servings am I consuming"? (e.g., 1/2 serving, 1 serving, or more) In the sample label, one serving of macaroni and cheese equals one cup. If you ate the whole package, you would eat two cups. That doubles the calories and other nutrient numbers, including the %Daily Values as shown in the sample label.

2. Calories (and calories from fat)  Calories provide a measure of energy  The calorie section of the label can help you manage your weight.  Only about 30% of your calories should come from fat.  Remember: the number of servings you consume determines the number of calories you actually eat (your portion amount).  A guide: 40 Calories is low, 100 Calories is moderate and 400 Calories or more is high

3. The nutrients Limit These Nutrients

Eating too much fat, saturated fat, trans fat, cholesterol, or sodium may increase your risk of certain chronic diseases, like heart disease, some cancers, or high blood pressure.

Get Enough of These

Eating enough of these nutrients can improve your health and help reduce the risk of some diseases and conditions.

Remember: You can use the Nutrition Facts label not only to help limit those nutrients you want to cut back on but also to increase those nutrients you need to consume in greater amounts.

5. Understanding the Footnote on the Bottom of the Nutrition Facts Label

This statement must be on all food labels.

6. The Percent Daily Value (%DV) 5%DV or less is low and 20%DV or more is high

Plain vs Fruit Yogurt

Glycemic Index  Consumption of carbohydrates causes insulin and

glucose levels in the blood to rise and fall  Glycemic index = a measure of how the ingestion of a particular food affects blood glucose levels  Foods with a high glycemic index cause quick and dramatic changes in glucose levels  Diets rich in high glycemic index foods are linked to increased risk of diabetes and heart disease  High glycemic: Bread, Pasta, Rice, Baked goods

 Low glycemic: Fruits, Vegetables, Whole grains Chapter 8

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Acceptable Macronutrient Distribution Ranges: Summary  Protein = 10–35% of total daily calories  Fat = 20–35% of total daily calories

 Carbohydrate = 45–65% of total daily calories

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Fiber—A Closer Look  Dietary fiber = nondigestible carbohydrates and

lignin that are present naturally in plants  Functional fiber = nondigestible carbohydrates isolated from natural sources or synthesized in a lab and added to a food or supplement  Total fiber = dietary fiber + functional fiber

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Types of Fiber  Soluble (viscous) fiber = fiber that dissolves in water or is broken down by bacteria in the large intestine  Slows the body’s absorption of glucose  Binds cholesterol-containing compounds

 Insoluble fiber = fiber that doesn’t dissolve in water  Makes feces bulkier and softer  Helps prevent constipation, hemorrhoids, and diverticulitis

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Sources of Fiber  All plant foods contain fiber, but processing can remove it  Good sources of fiber:      

Fruits (especially whole, unpeeled fruits) Vegetables Legumes Oats (especially oat bran) Whole grains and wheat bran Psyllium (found in some cereals and laxatives)

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Vitamins—Organic Micronutrients  Vitamins = organic (carbon-containing) substances needed in small amounts to help promote and regulate chemical reactions and processes in body cells.  Four vitamins are fat-soluble (A, D, E, and K)  Nine vitamins are water-soluble (C and the eight Bcomplex vitamins: thiamin, riboflavin, niacin, vitamin

B-6, folate, vitamin B-12, biotin, and pantothenic acid) Chapter 8

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Vitamins  Vitamins are abundant in fruits, vegetables, and grains; they are also added to some processed foods  If you consume too much or too little of a particular vitamin, characteristic symptoms of excess or deficiency

can develop  Vitamins commonly lacking in the American diet:    

Vitamin A Vitamin C Vitamin B-6 Vitamin E

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Minerals—Inorganic Micronutrients  Minerals = inorganic (non-carbon-containing) compounds needed in small amounts for regulation, growth, and maintenance of body tissues and functions  There are about 17 essential minerals:  Major minerals (those that the body needs in amounts

exceeding 100 mg per day) include calcium, phosphorus, magnesium, sodium, potassium, and chloride  Essential trace minerals include copper, fluoride, iodide, iron, selenium, and zinc

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Minerals  If you consume too much or too little of a particular mineral, characteristic symptoms of excess or deficiency can develop  Minerals commonly lacking in the American diet:  Iron = low intake can cause anemia  Calcium = low intake linked to osteoporosis  Potassium = low intake linked to elevated blood pressure

and bone mineral loss

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Water—A Vital Component  Human body is composed of about 60% water; you can live only a few days without water  Foods and fluids you consume provide 80–90% of

your daily water intake  Adequate intake to maintain hydration:  Women need to drink about 9 cups of fluid per day  Men need to drink about 13 cups of fluid per day

 Drink in response to thirst; consume additional fluids for heavy exercise Chapter 8

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Other Substances in Food: Antioxidants  Antioxidant = a substance that protects against the breakdown of body constituents by free radicals; actions include binding oxygen, donating electrons to free radicals, and repairing damage to molecules  Free radical = a chemically unstable, electron-seeking

compound that can damage cell membranes and mutate genes in its search for electrons

 Many fruits and vegetables are rich in antioxidants such

as vitamin C, vitamin E, selenium, and carotenoids

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Should You Take Supplements?  The Food and Nutrition Board recommends supplements only for certain groups:  Folic acid for women capable of becoming pregnant (400

µg/day)  Vitamin B-12 for people over age 50 (2.4 mg/day)

 Other possible situations for supplements:    

Vitamin C for smokers Iron for menstruating women Vitamin K for newborns People with certain special health concerns Chapter 8

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Leading Sources of Calories in the American Diet 1. Regular soft drinks (7.1% of total calories) 2. Cake, sweet rolls, doughnuts, pastries (3.6%) 3. Hamburgers, cheeseburgers, meat loaf (3.1%) 4. Pizza (3.1%) 5. Potato chips, corn chips, popcorn (2.9%) 6. Rice (2.7%) 7. Rolls, buns, English muffins, bagels (2.7%) 8. Cheese or cheese spread (2.6%) 9. Beer (2.6%) 10. French fries, fried potatoes (2.2%) Source: Block, G. 2004. Foods contributing to energy intake in the U.S.: Data from NHANES III and NHANES 1999–2000. Journal of Food Composition and Analysis 17: 439–447.

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Alternative Food Plans: Healthy Eating Pyramid

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Alternative Food Plans: Canada’s Food Guide

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Dietary Challenges for Special Population Groups: Athletes  Energy intake—adequate calories and nutrients  Carbohydrates—60 to 65% of total daily calories for most athletes, up to 70% for endurance athletes  Protein (grams per day per kilogram of body weight)  Endurance athletes: 1.2 to 1.4 grams  Heavy strength training: 1.6 to 1.7 grams

 Fluids—remain hydrated  14 to 22 oz of fluid two hours before strenuous event  6 to 12 oz every 15–20 minutes during exercise  Replace fluids after event (check body weight)

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A Personal Plan: Applying Nutritional Principles  Assess your current diet  Set goals for change  Try additions and substitutions to bring your

current diet closer to your goals  Plan ahead for challenging situations Make smart choices about nutrition! See the following recommendations.

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What Type of Food Should People Choose? The type of food that people eat is just as important as the amount.  Eat at least one dark green and one orange vegetable each day.  Have vegetables and fruit more often than juice.  Make at least half of your grain products whole grain each day.  Drink skim, 1% or 2% milk each day.  Have meat alternatives such as beans, lentils and tofu often.  Eat at least two Food Guide Servings of fish each week.  Include a small amount of unsaturated fat each day.  Satisfy your thirst with water. Chapter 8

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Lowering fat  It is best to reduce the total amount of fat in your diet and

reduce the amount of saturated and trans fats you consume.  Higher fat foods are often higher in saturated and trans fats. These kinds of fats put people at higher risk of cardiovascular disease.  Saturated fats are found in fatty meats, higher fat milk products, butter, lard, shortening, hard margarines and tropical oils such as coconut and palm oil.  Trans fats are found in many deep-fried foods, fast foods, salty snacks and baked goods made with shortening or partially hydrogenated vegetable oils. Chapter 8

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Lowering salt  Most people get more sodium than they need,

especially if they eat packaged, processed foods and meals made outside of the home.  Some of the foods that can be high in sodium include snack foods, such as crackers, nachos, potato chips and pretzels, cheese, gravies and sauces, processed luncheon meats, canned or dried soups and frozen meals.  People should compare the Nutrition Facts table on similar products and choose the one that has a lower number for the % Daily Value of sodium.

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Lowering sugar  Baked goods and desserts, such as cakes, candies,

chocolate, cookies, doughnuts, ice cream, muffins, pastries and pies, and sweetened cold and hot beverages, such as energy drinks, fruit flavoured drinks, soft drinks, sports drinks, hot chocolate and specialty coffees, can be high in sugar and should be limited. When cooking, try roasting, grilling, baking, stir-frying, steaming or poaching - all methods that require little or no added fat. For tips on preparing foods with little or no added fat, sugar or salt.

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Remember  Think before you eat!  Move! (energy balance)  Make a plan for yourself – it is your body, your

health!  Enjoy your life but do it in a smart way!

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