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Sport Books Publisher1 The Nutritional Connection Chapter 11.

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1 Sport Books Publisher1 The Nutritional Connection Chapter 11

2 Sport Books Publisher2 Learning Objectives: Become familiar with the anatomy and physiology of the digestive system Identify the nutritional requirements and components of a healthy diet Outline the official nutritional advice provided for Canadians Understand the unique nutritional needs of various populations Appreciate the effects of nutrition on athletic performance

3 Sport Books Publisher3 Introduction

4 Sport Books Publisher4 Introduction Promotion of energy and vigor Development of chronic illness and disease NUTRITIONAL HABITS

5 Sport Books Publisher5 Nutrition Basics Choose foods that provide the necessary nutrients Limit those foods associated with disease Don’t assume that a healthy diet needs to be fat-free, low-sugar, and high-fibre all the time When making food choices, consider: VARIETY BALANCE; and MODERATION

6 Sport Books Publisher6 The Digestive System

7 Sport Books Publisher7 The Digestive System The role of the digestive system is to: Produce energy from food ingested To transfer energy-rich nutrients, water, and electrolytes into your body’s internal environment Composed of numerous structures and organs that work together The digestive tract forms a continuous route from mouth to anus The contents of the digestive tract are actually part of the external environment until absorbed through the intestinal wall

8 Sport Books Publisher8 The Gastrointestinal Tract Digestive Tract Mouth Pharynx Esophagus Stomach Small intestine Large intestine (colon) Rectum Anus Glandular Organs Salivary glands Liver Gall bladder Pancreas

9 Sport Books Publisher9 Basic Processes of the Digestive System 1. Digestion 2. Secretion 3. Absorption 4. Motility

10 Sport Books Publisher10 Digestion Processes that dissolve and break down foods into molecules that can be absorbed by the body

11 Sport Books Publisher11 Secretion The release of substances from exocrine glands Works closely with the digestion process Includes many secretions, some of which are: Saliva by salivary glands Hydrochloric acid by the stomach Bile by the liver

12 Sport Books Publisher12 Absorption Uptake of digested molecules across a layer of epithelial cells lining the gastrointestinal wall Molecules enter the blood or lymph to be distributed to body cells

13 Sport Books Publisher13 Motility The muscular contractions that mix and move the contents of the digestive tract forward Propels the contents of the digestive tract forward Mixes food with digestive juices that promote digestion

14 Sport Books Publisher14 The Digestive System The digestive system aims to absorb maximally Waste material excreted via the gastrointestinal tract is called ‘feces’ Feces consist mainly of bacteria and undigested material (including fibre)

15 Sport Books Publisher15 Functional Overview of the Gastrointestinal Organs

16 Sport Books Publisher16 Functional Overview of GI Organs: The Salivary Glands Digestion begins in the mouth The mechanical breakdown of food is achieved by chewing Saliva produced by the salivary glands Three salivary glands in the head

17 Sport Books Publisher17 Saliva contains mucus that moistens and lubricates food Saliva also contains ‘amylase’ Amylase is an enzyme that catalyzes the breakdown of carbohydrates Functional Overview of GI Organs: The Salivary Glands

18 Sport Books Publisher18 Voluntary swallowing is initiated in the oropharynx (posterior mouth) The bolus of food moves to the pharynx Involuntary swallowing occurs in the esophagus ‘Peristalsis’ is the involuntary contraction of muscles and is involved in moving food to the stomach Functional Overview of GI Organs: The Mouth and Throat

19 Sport Books Publisher19 A sac-like organ Serves as a storage site Dissolves and partially digests food Prepares food for optimal digestion and absorption in the small intestine Functional Overview of GI Organs: The Stomach

20 Sport Books Publisher20 Glands in the stomach secrete hydrochloric acid (HCl) HCl dissolves particulate matter in food (except fat) HCl also kills some bacteria that is ingested with food Functional Overview of GI Organs: The Stomach

21 Sport Books Publisher21 The precursor ‘pepsinogen’ forms the enzyme ‘pepsin’ Pepsin begins protein digestion Amylase (from the salivary glands) continues to break down carbohydrates Functional Overview of GI Organs: The Stomach

22 Sport Books Publisher22 Little absorption occurs across the stomach wall Functional Overview of GI Organs: The Stomach

23 Sport Books Publisher23 Site of completion of digestion Site where most absorption occurs Approximately nine feet in length Three segments: Duodenum Jejunum Ileum Most absorption occurs in the duodenum and jejunum (vitamins, minerals, water) Functional Overview of GI Organs: The Small Intestine

24 Sport Books Publisher24 Hydrolytic Enzymes Monosaccharides Carbohydrates AMYLASE

25 Sport Books Publisher25 Hydrolytic Enzymes Amino Acids Proteins PEPSIN

26 Sport Books Publisher26 Hydrolytic Enzymes Fatty Acids Fats LIPASE

27 Sport Books Publisher27 Secretes digestive enzymes Secretes an alkaline fluid mainly of bicarbonate ions The alkaline fluid counteracts the acidity of the contents of the stomach to protect the small intestine Alkaline substance also maintains an optimal pH range for enzymatic functions Functional Overview of GI Organs: The Pancreas

28 Sport Books Publisher28 Secretes ‘bile’ Bile contains cholesterol, bicarbonate ions, and bile salts Bile salts are essential for fat digestion and absorption Bile is stored in the gall bladder Functional Overview of GI Organs: The Liver

29 Sport Books Publisher29 Absorption in the Small Intestine Absorption within the small intestine occurs via: 1.DIFFUSION (Fatty Acids) 2.OSMOSIS (Water) 3.ACTIVE TRANSPORT (Mineral Ions) 4.CARRIER-MEDIATED TRANSPORT (Monosaccharides and Amino Acids)

30 Sport Books Publisher30 Functional Overview of GI Organs: The Large Intestine Upon reaching the large intestine, very little water remains, and salts and undigested material are left Here, the material is further concentrated by further reabsorption of salt and water

31 Sport Books Publisher31 Functional Overview of GI Organs: The Large Intestine When reabsorption is complete, the feces move to the rectum as a result of involuntary contractions (peristalsis) The coordinated relaxation of sphincter muscles results in defecation

32 Sport Books Publisher32 Nutritional Requirements: Types and Sources of Nutrients

33 Sport Books Publisher33 Nutrition The science of food and how the body uses it in health and disease

34 Sport Books Publisher34 Essential Nutrients 1. Proteins 2. Fats 3. Carbohydrates 4. Vitamins 5. Minerals 6. Water In this context, ‘essential’ refers to nutrients that the body is unable to manufacture (or not in sufficient quantities) They must be obtained from the diet

35 Sport Books Publisher35 Essential Nutrients Necessary for energy Needed for the building and maintenance of tissues Relied upon for the regulation of body functions

36 Sport Books Publisher36 Energy-Providing Nutrients Three nutrients provide the body with energy 1. Proteins 2. Fats 3. Carbohydrates

37 Sport Books Publisher37 Energy Measurements Energy is expressed in ‘kilocalories’ 1 kilocalorie = 1000 calories Kilocalorie = Calorie (note capital ‘C’) 1 kilocalorie = heat required to raise the temperature of 1kg of water 1°C An average person requires approximately 2000 kilocalories per day

38 Sport Books Publisher38 FATS 9 Cal/g ALCOHOL 7 Cal/g CARBOHYDRATES 4 Cal/g PROTEINS 4 Cal/g Calorie Densities of Various Energy Sources

39 Sport Books Publisher39 Proteins Found in every living cell Act as structural components for: 1. Muscles 2. Bones 3. Blood 4. Enzymes 5. Some hormones 6. Cell membranes

40 Sport Books Publisher40 Proteins Composed of chains of amino acids 20 commonly recognized amino acids Nine essential (can not be synthesized) amino acids 1.Histidine 2.Isoleucine 3.Leucine 4.Lysine 5.Methionine 6.Phenylalanine 7.Threonine 8.Tryptophan 9.Valine

41 Sport Books Publisher41 Protein Individual sources of protein are ‘complete’ if they supply all nine essential amino acids Complete protein sources include animal products such as meat, cheese, fish, eggs, poultry and milk

42 Sport Books Publisher42 Protein ‘Incomplete’ protein sources include those foods that do not contain all nine essential amino acids Usually from plant sources such as grains, beans, peas, and nuts Still good sources of amino acids Foods must be combined to get all amino acids (rice and beans for example)

43 Sport Books Publisher43 Protein Protein should comprise 10-15% of total caloric intake Protein consumed in excess of needs is stored as fat Inadequate protein consumption can lead to muscle wasting

44 Sport Books Publisher44 Fats Also known as lipids Concentrated source of energy Fat serves to 1.Provide a source of energy 2.Insulate the body 3.Cushion organs 4.Aid the absorption of fat-soluble vitamins 5.Add flavour and texture to foods

45 Sport Books Publisher45 Fats Fats in food are mostly triglycerides Include a glycerol (an alcohol) Three fatty acid molecules

46 Sport Books Publisher46 Fats Fats can be classified as 1.Saturated 2.Monounsaturated 3.Polyunsaturated  Based on the degree of saturation or number of double bonds that exist between carbon atoms  No double bonds = saturated  One double bond = monounsaturated  Two or more double bonds = polyunsaturated

47 Sport Books Publisher47 Saturated Fat Monounsaturated Fat Polyunsaturated Fat

48 Sport Books Publisher48 Saturated Fats Food usually contains more than one type of fat The dominant fat determines the characteristics of the fat Saturated fats are solid at room temperature Saturated fat is found predominantly in animal products Saturated fat has also been linked to cardiovascular disease

49 Sport Books Publisher49 Unsaturated Fats Monounsaturated and polyunsaturated fats usually come from plant sources Unsaturated fat is liquid at room temperature (oil) More desirable, not linked to cardiovascular disease Unsaturated fats appear to lower blood cholesterol Also shown to reduce the risk of heart disease

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51 Sport Books Publisher51 Hydrogenation Processed plant oils can be high in saturated fat Tropical oils (such as palm oil and coconut oil) used in processed foods are high in saturated fats Hydrogenated fats and oils are created from unsaturated fats are used to prevent spoiling and to add texture

52 Sport Books Publisher52 Cholesterol Elevated intake of saturated fats may increase blood cholesterol levels Hydrogenation produces trans fatty acids that may increase blood cholesterol Increased blood cholesterol and triglyceride levels have been implicated with the development of heart disease

53 Sport Books Publisher53 Carbohydrates Primary source of energy (60% of daily Calories) Three groups based on the number of saccharides Monosaccharides and disaccharides are considered sugars Polysaccharides are considered starches

54 Sport Books Publisher54 Monosaccharides Simplest sugar Include glucose, fructose, galactose Glucose makes up the blood sugar (the brain, nervous system are fueled by glucose exclusively) Glucose found in vegetables, fruit, honey Fructose found in fruits and berries

55 Sport Books Publisher55 Disaccharides Two monosaccharides One monosaccharide is always glucose, e.g., lactose = glucose + galactose Many ‘hidden’ sugars in food Primary concern related to sugar consumption is dental cavities

56 Sport Books Publisher56 Polysaccharides Found in vegetables, fruit, grains Complex carbohydrates composed of chains of many sugars Starches often contain many vitamins, minerals, water, protein Dietary fibre is an important complex carbohydrate

57 Sport Books Publisher57 Carbohydrates Liver and muscles use glucose for carbohydrate storage in the form of glycogen Carbohydrates consumed in excess of storage capacity as glycogen are stored as fat An important component of the diet for athletes competing in events of long duration

58 Sport Books Publisher58 Vitamins Serve as coenzymes in chemical reactions ‘Organic’ because they contain carbon atoms Required in small amounts Necessary for 1.Growth 2.Reproduction 3.Health Maintenance

59 Sport Books Publisher59 Vitamins Two classifications, 1.Water-soluble vitamins; and 2.Fat-soluble vitamins  Based on the ability to dissolve in either water or fat tissue, respectively

60 Sport Books Publisher60 Water-soluble Vitamins Not stored Excess eliminated in the urine Include vitamin C and B-complex vitamins Dissolve quickly in water, so overcooking fruits and vegetables in water will result in the vitamins being lost to the water

61 Sport Books Publisher61 Fat-soluble Vitamins Includes vitamins A,D,E,K When taken in excess, these vitamins are stored in fat tissue Over-consumption of these vitamins (especially A and D) can result in toxicity

62 Sport Books Publisher62 Antioxidants Formed from vitamins Aid in preserving healthy cells When the body breaks down fats, or uses oxygen, free radicals are formed Free radicals can damage cell membranes and mutate genes Antioxidants react with free radicals to decrease their negative effects Include vitamins E, C, beta carotene (from vitamin A)

63 Sport Books Publisher63 Minerals Numerous functions in the body ‘Inorganic’ because they do not contain carbon atoms Necessary for 1.Structural elements (teeth, hormones, muscles) 2.Regulation of body functions (muscle contractions, blood clotting, heart function) 3.Aid in the growth and maintenance of body tissues 4.Catalytic action in energy release

64 Sport Books Publisher64 Minerals Macronutrients (major minerals) are found in relatively large amounts in the body Calcium Phosphorus Magnesium Sulfur Sodium Potassium Micronutrients (trace elements) are needed in small amounts Zinc Iron Copper Fluoride Iodine Selenium Approximately 17-21 identified essential minerals

65 Sport Books Publisher65 Vitamins and Minerals Needed in small amounts Essential component to good health Consumption of too little or too much can have detrimental effects To ensure adequate intake, eat a balanced diet with variety

66 Sport Books Publisher66 Water Large component of our bodies and food Important for: 1. Nutrient transport 2. Waste transport 3. Digestion & absorption 4. Regulation of body temperature 5. Lubrication 6. Chemical reactions

67 Sport Books Publisher67 Water Body water is lost through: 1. Urine 2. Feces 3. Sweat 4. Evaporation in lungs  Excessive water loss through: 1. Illness 2. Exercise 3. Hot environment 4. Consumption of coffee, tea, alcohol

68 Sport Books Publisher68 Water  Need to consume approx. 1mL of water for every Calorie burned  About 8 cups of fluid per day  More if you are active or live in a warm climate  Weakness or fatigue can be a sign of dehydration

69 Sport Books Publisher69 Fibre  Fibre includes plant substances that cannot be digested by the body  Adds bulk to feces to facilitate elimination  A large intake of fibre can lead to intestinal gas

70 Sport Books Publisher70 Fibre  Rich sources include: 1. Fruit 2. Legumes 3. Oats 4. Barley  Other sources include: 1. Wheat 2. Grains 3. Vegetables 4. Whole grain foods

71 Sport Books Publisher71 Fibre Soluble fibre  Lowers blood cholesterol  Slows absorption of glucose Insoluble fibre  Facilitates feces elimination  Can prevent constipation, lower intestinal tract cancer

72 Sport Books Publisher72 Nutrition Guidelines and Recommendations

73 Sport Books Publisher73 Recommended Nutrient Intakes RNI’s Designed to meet the needs of virtually the entire healthy population RNI’s exceed the requirements of most people Allow for a margin of safety, taking into account individual variation Expressed as a daily requirement Should be regarded as an average recommended intake over a period of days or weeks

74 Sport Books Publisher74 Recommended Daily Intakes RDI’s A reference standard for nutrition labeling purposes RDI’s represent the highest RNI that exists for a nutrient for a particular age group Expressed as the percentage of RDI of the nutrient on labels Two RDI’s - one for children ( 2 yrs)

75 Sport Books Publisher75 Nutrition Recommendations for Canadians Eight recommendations made by Health and Welfare Canada Outline desirable characteristics of the Canadian diet Recommendations are intended for educators and health professionals User-friendly version includes 5 general statements to consider when choosing what to eat These statements are as follows…

76 Sport Books Publisher76 Enjoy a variety of foods

77 Sport Books Publisher77 Emphasize cereals, breads, other grain products, vegetables, and fruits

78 Sport Books Publisher78 Choose lower-fat dairy products, leaner meats, and foods prepared with little or no fat

79 Sport Books Publisher79 Achieve and maintain a healthy body weight by enjoying regular physical activity and healthy eating

80 Sport Books Publisher80 Limit salt, alcohol, and caffeine

81 Sport Books Publisher81 Canada’s Food Guide to Healthy Eating Translates nutrient recommendations into a food group plan A guide to ensure a balanced intake of essential nutrients Meets the needs of all Canadians four years of age and older Aimed at the general population

82 Sport Books Publisher82

83 Sport Books Publisher83 Food Groups Five food groups: 1. Grain Products 2. Vegetables and fruits 3. Milk products 4. Meat and alternatives 5. Other foods (such as junk food)

84 Sport Books Publisher84 Food Choices The rainbow design of the Food Guide is a visual representation of the relative amounts of each food group recommended

85 Sport Books Publisher85

86 Sport Books Publisher86 Food Servings Amount of food needed each day from the food groups varies according to: 1. Age 2. Body size 3. Gender 4. Activity level 5. If you are pregnant 6. If you are breast feeding

87 Sport Books Publisher87 Food Servings A range of servings is given in order to include the energy needs of all individuals For example, a sedentary woman may require the lower number of servings, while an active male may choose the higher number of servings

88 Sport Books Publisher88 Directional Statements within Canada’s Food Guide Enjoy a variety of foods from each food group every day Choose lower-fat foods more often Choose whole grain and enriched products more often

89 Sport Books Publisher89 Directional Statements within Canada’s Food Guide Choose dark green and orange vegetables and orange fruit more often Choose lower-fat milk products more often

90 Sport Books Publisher90 Directional Statements within Canada’s Food Guide Choose leaner meats, poultry and fish, as well as dried peas, beans, and lentils more often

91 Sport Books Publisher91 Nutrition Questions and Answers

92 Sport Books Publisher92

93 Sport Books Publisher93 Nutritional value of fast foods vary Fat (especially saturated fat) and cholesterol are major concerns for making healthy choices A limited variety of foods containing dietary fibre exists Healthy alternatives are beginning to be offered, including salads, lower-fat meats and milk products, and whole wheat breads Eaten in excess, fast foods can be detrimental to health due to high Calories, fat, and salt

94 Sport Books Publisher94

95 Sport Books Publisher95 Labels are standardized presentations of the nutrient content of food Consists of (based on serving size): 1. Heading 2. Serving size 3. Values for energy 4. Protein 5. Fat 6. Carbohydrate  May also include: 1. Breakdown of fats (saturated, monounsaturated, polyunsaturated) 2. Breakdown of carbohydrates (sugar, starch, fibre) 3. Sodium and potassium 4. Vitamins and minerals

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97 Sport Books Publisher97 Concerns about environmental contaminants in foods (pesticides) Presence of potentially dangerous additives Threat of bacteria and microorganisms causing illness Elderly people and children have a higher risk of suffering severe illness as a result of food poisoning

98 Sport Books Publisher98 Most food-borne illness is due to bacteria and is preventable through proper food preparation and storage Salmonella is common in eggs, meat, milk, and poultry Staphylococcus aureus is common in ham, cheese, eggs, and seafood More serious bacteria include Clostridium botulinum and Escherichia coli (E-coli), which usually arise from improperly canned foods

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100 Sport Books Publisher100 Various reasons cited for vegetarianism Philosophical, health, environmental reasons Can provide necessary nutrients Requires planning Children and pregnant women require special individual guidance Many types of vegetarianism Potential concern in obtaining all essential amino acids May be difficult to get adequate intakes of vitamin B 12, calcium, iron, and zinc

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102 Sport Books Publisher102 Most nutritionists agree that, given a balanced diet, supplements are not necessary Mega-doses of supplements (especially fat-soluble vitamins) may lead to toxicity If you choose to supplement, consult with a public health nutritionist, dietician, or doctor

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104 Sport Books Publisher104 The primary health concern associated with sugar intake is cavities Also, calories consumed in the form of sugar, beyond caloric requirements, is stored as fat Therefore, a high sugar diet can lead to obesity Obesity is a risk factor for developing diabetes and a host of other diseases

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106 Sport Books Publisher106 Aging leads to a lower total energy requirement as a result of less activity and a lower metabolic rate Leads to lower food intake among seniors May not have adequate vitamin and mineral intakes Constipation may further add to a declining interest in food Other diseases may also affect nutrition, including dental problems, swallowing disorders, mood disorders, and gastrointestinal disorders Psychosocial issues may also negatively affect nutrition

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108 Sport Books Publisher108 Ergogenic Aids and Supplements Canadian diet seems to be adequate to meet protein needs of athletes Athletes should focus on maintaining a balanced diet with adequate Calories rather than supplementing Carbohydrate loading can increase muscle glycogen stores for endurance-type competition, but should be supervised by a qualified coach Caffeine has been shown to enhance endurance performance but should be attempted on a trial basis, if at all

109 Sport Books Publisher109 Pre-Event Meals Meals before an event should be high in carbohydrates and low in fat Only familiar foods should be eaten before an event to avoid any strange or surprising reactions or feelings

110 Sport Books Publisher110 Hydration The need for water is increased during exercise because of increased losses through the lungs and sweat Needs also increased in warm and humid environments Drink early (prior to exercise) Drink often (during exercise) Drink after exercise Cool drinks increase performance by cooling the body effectively

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