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Transcript
Chapter 5 Nutrition and Supplements Chapter 5 Extended Lecture Outline Nutrition Basics o Nutrition is the science of the substances that are found in food that are essential to life o Major Roles of nutrients Growth, repair and maintenance of all tissues Regulation of body processes Production of energy o Essential nutrients must be supplied by the diet o Six Classes of nutrients Carbohydrates (CHO) Fats (Lipids) Proteins Water Vitamins Minerals o Vitamins, minerals and water are micronutrients which are necessary for regulating normal body functions o Nutrient Dense Foods: Supply adequate amounts of vitamins and minerals in relation to caloric value o Junk Foods: Provide excessive calories from fat and sugar in relation to vitamins, and minerals – not nutrient dense Energy Sources o Carbohydrates Body’s most efficient source of energy Intake should account for 55-70% of total caloric intake o Sugars: simple (sugars) or complex (starch and most forms of fiber) Monosaccharides: Simple sugars found in fruit, syrups, honey and glucose (blood sugar) Disaccharides: Milk sugar (lactose), table sugar (sucrose) – combination of two monosaccharides Amount of sugar eaten should account for less than 15% of the total caloric intake o Starches Complex Carbohydrates Made up of long chains of glucose units Food sources include rice, potatoes, and breads Body cannot use starches directly from food sources for energy – broken down during digestion and converted to glucose (glycolysis) Glucose that is not needed for immediate energy is stored s glycogen in the liver and muscle cells Body can only store limited amounts of glucose as glycogen – extra amounts of glucose is converted to body fat o Fiber Two kinds of dietary fiber: Soluble and Insoluble Soluble fiber: oatmeal, legumes and some fruits Insoluble fiber: whole grain breads and bran cereals Fiber passes through the intestinal tract and adds bulk as it is not digestible Aids in normal elimination of wastes through the digestive tract Believed to reduce the risk of colon cancer and coronary artery disease Recommended amount of fiber in the diet 25 grams per day o Fats Most concentrated source of energy Recommended daily intake should be limited to less than 30% of total calories with saturated fat less than 10% Prentice, Principles of Athletic Training , 15e LO-5 | 1 Chapter 5 Nutrition and Supplements Fats may be saturated or unsaturated Unsaturated fat: Omega – 3 fatty acids (found in cold-water fish) have capability to reduce likelihood of diseases such as heart disease, stroke and hypertension Trans fatty acids – physical properties of saturated fatty acids. Found in cookies, crackers, dairy products, meats and fast food. Increase risk of heart disease by boosting levels of bad cholesterol. o Other fats Phospholipids and sterols represent the remaining 5 percent of fats Cholesterol is best know sterol Fat substitutes: Simplese and Olean, contain no cholesterol and 80% fewer calories than similar products made with fat o Proteins Make up the major structural components of the body Needed for growth, maintenance, and repair of all body tissues Protein intake should be around 12-15% of total calories Amino Acids: basic units that make up proteins, essential amino acids are obtained through food No advantage to consuming more protein, the body must convert the excess to fat for storage Protein supplementation is not necessary Increased physical activity increases a person’s need for energy, not necessarily for protein Regulator Nutrients o Vitamins Thirteen vitamins have specific roles in the body (Table 5-1) Classified into fat-soluble (dissolved in fat and stored in the body) and water-soluble (dissolved in watery solutions and are not stored) o Fat-Soluble: Vitamins A, D, E, and K (found in fatty portions of food and in oils and stored in the body’s fat) o Water-Soluble: Vitamins C (asorbic acid), B-Complex (thiamin, riboflavin, niacin, B6, folate, B12, biotin and pantothenic acid): Should be supplied in diet each day o Antioxidants: Vitamin C, Vitamin E, and beta-carotene o May prevent premature aging, certain cancers and heart disease o Protects vital cell components from destructive effects of certain agents, including oxygen o Vitamin Deficiencies: Vitamin deficiency diseases are rare Vitamin supplements can cause toxic effects if taken in large enough quantities (Table 51) o Minerals (Table 5-2) Most minerals are stored in the body, especially in the liver and bones Have essential roles in the body and must be supplied by the diet Include Magnesium, sodium, potassium, iron, calcium, copper, zinc, iodine, fluorine, and phosphorus o Water Most essential of all the nutrients Accounts for approximately 60% of body weight – varies due to age and percent of body fat by (+/- 10%) Adequate supply of water is necessary for: Energy production in all cells Assists with digestion and maintains proper environment inside and outside cells Temperature control Elimination of waste products of nutrient and body metabolism Average adult requires a minimum of 2.5 liters or about 10 glasses of water a day o Electrolyte Requirements Sodium, chloride, potassium, magnesium and calcium are electrically charged ions dissolved in body water Prentice, Principles of Athletic Training , 15e LO-5 | 2 Chapter 5 Nutrition and Supplements Electrolytes maintain the balance of water inside and outside the cell Electrolyte losses can produce muscle cramping and heat intolerance Thirst is not an indicator of hydration Nutrient Requirements and Recommendations o A nutrient requirement is the amount of the nutrient that is needed to prevent the nutrient’s deficiency disease o U.S. Recommended Dietary Allowances (US RDA) have been changed to Dietary Reference Intakes (DRI’s) o DRI’s include recommended intakes (RDA’s) and also tolerable upper intake levels (UL’s) RDA: help individuals meet their daily nutritional requirements UL’s: help individuals avoid harm from consuming too much of a nutrient EAR (Estimated Average Requirements): are the average daily nutrient intake level estimated to meet the requirement of half the healthy individuals in a particular age group AI (Adequate Intake): the recommended average daily intake level based on experimentally developed estimates of nutrient intake that are used when the RDA cannot be determined (Appendix E) o Food Labels In early 1990’s new format of labels with information in the form of percentages of daily values based on a standard 2,000 calorie diet o MyPlate (Figure 5-3) My Plate was introduced in 2011 by USDA to replace MyPyramid Balance Calories Foods to Increase Foods to Reduce MyPyramid was introduced in 2005 by USDA – replaces the Food Guide Pyramid Dietary Supplements o No scientific basis for ingesting levels of nutrients above the DRI levels. Exercise increases the need for energy, not for proteins, vitamins and minerals o Vitamin Supplementation Many athletes believe taking large amounts of vitamin supplements can lead to superior health and performance A megadose of a nutrient supplement is essentially an overdose, as the amount far exceeds the DRI Vitamin requirements do not increase during exercise If an athlete is not eating a well balanced diet, taking a multiple vitamin once a day would be helpful o Mineral Supplementation Calcium Supplements: Calcium most abundant mineral in the body, essential for bones and teeth, muscle contraction and conduction of nerve impulses If calcium intake is too low to meet needs, the body can remove calcium from the bones – leading to osteoporosis Calcium AI for young adults is 1,000 mg (an 8 ounce glass of milk contains 300 mg’s) High protein diets and alcohol consumption also increase calcium excretion from the body Exercise causes calcium to be retained in bones o Individuals that are lactose intolerant (dairy products upset their stomachs, lack lactase enzyme to digest milk sugar) may need supplementation Calcium supplementation may be necessary preferably as calcium carbonate or citrate rather than phosphate o Iron Supplements Iron is needed to properly form hemoglobin Anemia (iron deficiency) reduces the oxygen carrying ability of the red blood cells, so muscles cannot obtain enough oxygen to generate energy. Prentice, Principles of Athletic Training , 15e LO-5 | 3 Chapter 5 Nutrition and Supplements o o o Supplementation according to the DRI may be required Protein Supplementation To build muscles, athletes should consume 1-1.5 grams of extra protein per kilogram (0.5 – 0.7 grams per pound) of body weight every day An active adult will most likely require 0.6 gram per pound or 66 percent more than the DRI Creatine Supplementation Creatine is a naturally occurring organic compound synthesized by the kidneys, liver and pancreas Creatine also obtained from eating meat and fish that contain approximately 5 grams per kilogram Integral role in energy metabolism Two Types of Creatine Free Creatine Phosphocreatine (Stored in skeletal muscle and used during anaerobic activity to produce ATP with assistance from enzyme creatine kinase) Phosphocreatine (Stored in skeletal muscle and used during anaerobic activity to produce ATP with assistance from enzyme creatine kinase) Physiological effects Increases resynthesis of ATP; allows for increased intensity in a workout Functions as lactic acid buffer; prolongs maximal effort and improving exercise recovery time during maximal intensity activities Stimulates protein synthesis Decreases total cholesterol; improving HDL-to-LDL ratio Decreases total triglycerides Increases fat-free mass Side Effects Weight Gain, gastrointestinal disturbances and renal dysfunction No long-term side effects noted Dosage Loading phase – ingest .3 grams per kilogram of bodyweight per day, dosage should be split over 4-5 times per day with approximately 16 ounces of water Loading phase lasts for 5 days After loading phase for maintenance should take .03 grams per kilogram of bodyweight for a month Wash-out phase – No supplementation for 1 month August 2000, NCAA Committee on Competitive Safeguards and Medical Aspects of Sports banned distribution of all muscle-building substances, including creatine by NCAA institutions. The use of creatine itself is not banned. Herbal Supplements (Focus Box 5-1) Herbs are used as alternatives to drugs and medicines Herbs can offer the body nutrients that are reported to nourish the brain, glands and hormones Herbs do not need to be taken with food as they provide their own digestive enzymes Herbs are not drugs but rather are body balancers that work with the body’s functions so it can heal and regulate itself No federal or governmental controls regulating sales Using Ephedrine Ephedrine is a stimulant used in diet pills, illegal recreational drugs and legitimate over-the-counter medications to treat congestion and asthma Similar to an amphetamine December 2003, FDA banned the use of ephedrine as a dietary supplement NCAA, NFL, NBA, minor league baseball and the USOC have banned the use of ephedrine Prentice, Principles of Athletic Training , 15e LO-5 | 4 Chapter 5 Nutrition and Supplements Adverse reactions: heart attack, stroke, tachycardia, paranoid psychosis, depression, convulsions, fever, coma, vomiting, palpitations, hypertension and respiratory depression o Glucose Supplements Ingesting large quantities of glucose (honey, candy bars, or pure sugar) immediately before physical activity may have significant impact on performance The increase in glucose (blood sugar) stimulates the release of hormone insulin Insulin allows cells to use the circulating glucose so that blood sugar levels soon return to normal Recent evidences indicates that eating large quantities of CHO’s is beneficial Eating and Drinking Practices o Caffeine Consumption Caffeine is a central nervous system stimulant Large amounts of caffeine cause nervousness, irritability, increased heart rate and headaches Caffeine enhances the use of fat during endurance exercise, thus delaying the depletion of glycogen stores – this delay would help endurance performance Caffeine also makes calcium more available to the muscle during contraction – allows muscle to work more efficiently Olympic officials consider caffeine a drug and may not be found in a competitors blood level greater than that resulting in drinking 5-6 cups of coffee o Alcohol Consumption Each gram of pure alcohol (ethanol) supplies seven calories Sources of alcohol supply little nutritional value Effects of Alcohol Depressant effects on CNS – decreased physical coordination, slowed reaction times and decreased mental alertness Increases production of urine – diuretic effect o Eating Organic, Natural or Health Foods Organic foods are grown without the use of synthetic fertilizers and pesticides All foods (except water) are organic – they contain the element carbon No advantage to consuming organic food products Natural Foods are subjected to little processing and contain no additives such as preservatives or artificial flavors Processing can protect nutritional value Preservatives save food that would otherwise spoil o Vegetarianism Vegetarians use plant foods to form the foundation of their diet; animal foods are either totally excluded or included in a variety of eating patterns Total vegetarians or vegans: Consume plant but no animal foods; meat, fish, poultry, eggs and dairy products are excluded from their diet Lactovegetarians: Consume milk products along with plant foods; meat, fish, poultry and eggs are excluded from their diet Ovolactovegetarians: Consume dairy products and eggs in their diet along with plant foods; meat, fish, and poultry are excluded Semivegetarians: Consume animal products but exclude red meats. o Pre-event Nutrition The importance and content of the pre-event meal has been heatedly debated among coaches, athletic trainers, and athletes. The trend has been to ignore logical thinking about what should be eaten before competition and to upholding the tradition of “rewarding” the athlete for hard work by serving foods that may hamper performance. For example, the traditional steak-and-eggs meal before football games is great for coaches and athletic trainers; however, the athlete gains nothing from this meal. The important point is that too often people are concerned primarily with the pre-event meal and fail to realize that the nutrients consumed over several days before competition are much more important than what is eaten three hours before an event. Prentice, Principles of Athletic Training , 15e LO-5 | 5 Chapter 5 Nutrition and Supplements o o o o The purpose of the pre-event meal should be to maximize carbohydrate stored in the muscles as well as blood glucose. It has been suggested that the athlete consume carbohydrates 3-4 hours prior to practice or competition. But it has also been suggested that consuming carbohydrates immediately prior to competition causes an increased release of insulin, which increases the rate at which muscles burn carbohydrate thus lowering blood glucose levels (hypoglycemia). Different carbohydrates are digested and absorbed at different rates. The glycemic index (GI) is a scale that indicates the how much different types of carbohydrate effects blood glucose levels.73 Consuming foods that have a low to medium GI prior to an event is recommended because they produce only small fluctuations in blood glucose and insulin levels and release energy more slowly over a longer time period. Ingesting carbohydrates that have a high GI within an hour of exercise may actually lower blood glucose. (Figure 5-4) lists the glycemic index range for common foods. Additionally the foods selected should minimize gastrointestinal distress, and should be foods that the individual athlete prefers. It is also critical to make certain that the athlete is appropriately hydrated. Liquid Food supplementation Recently (Gatorade nutrition shake, exceed) have been recommended as effective preevent meals Supplements supply 225-400 calories per average serving Athlete’s using these supplements report elimination of usual pre-game symptoms of dry mouth, abdominal cramps, leg cramps, nervous defecation and nausea Advantage of liquid supplements is that they clear both the stomach and the upper bowel before game time, thus making available the caloric energy that would otherwise still be in an unassimilated state Eating Fast Foods (Table 5-3) Biggest concern of eating fast foods is 40-50% of the calories consumed are from fat More fast food restaurants have broadened their menus to include better food choices such as whole wheat breads and rolls, salad bars, and low-fat milk products Selecting fast foods (Focus box 5-3) Low Carbohydrate Diets Many different versions, all of which recommend a strict reduction in the consumption of carbohydrates Replace carbohydrates with a high fat and moderate protein Overweight individuals became overweight due to a condition called hyperinsulinemia (elevated insulin levels in the blood) Restricting CHO intake puts the body into a state of ketosis in which blood glucose levels stabilize, insulin level drops, and because the body is burning fat, fairly rapid weight loss occurs Glycogen Supercompensation Maximizing the amount of glycogen that can be stored can be beneficial for endurance events Athletes can increase glycogen supplies in muscle and liver by reducing the training program a few days before competing and by significantly increasing CHO intake during the week before the event (glycogen supercompensation) Reducing training for at least 48 hours before competition can eliminate any metabolic waste products that may hinder performance High CHO diet restores glycogen levels in muscle and the liver The quantity of glycogen stored in the muscle directly affects the endurance of that muscle Accomplished over a six day period divided into three phases Phase I: (days 1 & 2) training should be hard and dietary intake of CHO’s restricted Phase II: (days 3-5) training is cut back and the individual eats plenty of CHO’s Phase III: (day 6) the day of event – during which a normal diet must be consumed Prentice, Principles of Athletic Training , 15e LO-5 | 6 Chapter 5 Nutrition and Supplements Only of value in long-duration events that produce glycogen depletion such as a marathon Recommended not to be done more than 2-3 times a year o Recommendations for Restoring Muscle Glycogen and Exercise When the time period between exercise sessions is relatively short (less than eight hours), the athlete should begin consuming carbohydrates to restore supplies of muscle glycogen as soon as possible after the workout to maximize recovery between sessions. Ideally the foods should have a high glycemic index. Given that complete muscle glycogen restoration takes at least twenty to twenty-four hours, athletes should not waste time. They should ingest approximately 0.45 to 0.55 gram of carbohydrate per pound of body weight for each of the first four hours after exercise or until they eat their next large meal. During this period, nutrient-rich carbohydrate foods, such as fruits and vegetables or a high-carbohydrate drink, are recommended. Over a twenty-four-hour period, carbohydrate intake should range from 2.3 grams to as much as 5.5 grams per pound of body weight, depending on the intensity of the activity. Pasta, potatoes, oatmeal, and sports drinks are recommended. It has been suggested that adding protein to a carbohydrate supplement enhances aerobic endurance performance above that which occurs with carbohydrate alone, but the reason for this improvement in performance has not been established. Most evidence supports a 4:1 carbohydrate to protein ratio, while others argue for a oneto-one or three-to-one ratio. Peanut butter and tuna are recommended as good sources of protein. o Fat Loading Some endurance athletes have used fat loading in place of CHO loading to have a better source of energy at their disposal Deleterious effects outweigh any benefits Can cause cardiac protein and potassium depletion, causing arrhythmias and increased levels of serum cholesterol Body Composition and Weight Control o Body Composition Ideal body weight often determined by age related height and weight charts – these charts are inaccurate (involve broad ranges and often fail to take individual body types into account) Body composition refers to both the fat and nonfat components of the body Percentage of body fat = the portion of total body weight composed of fat tissue Lean body weight = the total body weight that is composed of nonfat or lean tissue which includes muscles, tendons, bones and connective tissue Average college-aged female has 20-25% of total body weight made up of fat and average college-aged male has between 12-15%. Endurance female athletes 10-18% and males 8-12% body fat Body fat percentages should not go below 3% in males and 12% in females as the internal organs tend to lose their protective padding of essential fat, potentially subjecting them to injury. Obestiy – Excessive amount of fat, females over 30% and males over 20%. Two factors determine the amount of fat in the body – the number of fat or adipose cells and the size of the adipose cell Adipose cells store triglyceride (a form of liquid fat) – the liquid fat moves in and out of the cell according to energy needs The greatest amount of fat is used in activities of moderate intensity and long duration One pound of body fat is made up of approximately 3,500 calories stored as triglyceride within the adipose cell o Assessing Body Composition Several methods are used: hydrostatic or underwater weighing, measurement of skinfold thickness, and measurement of electrical impedance Prentice, Principles of Athletic Training , 15e LO-5 | 7 Chapter 5 Nutrition and Supplements o o o o o o o Skinfold technique measures the thickness of the subcutaneous fat layer with skinfold calipers Accuracy is relatively low – error is plus or minus 3 – 5% Technique by Jackson and Pollack measures thigh, triceps, suprailiac, abdominal, and chest Hydrostatic Weighing involves placing a subject in underwater tank to determine body density Tank is expensive and technique is very time consuming Bioelectrical impedance involves the measurement of resistance to the flow of electrical current through the body between selected points Fat is poor conductor of electrical energy, and lean tissue is good conductor Impedance levels can be affected by levels of hydration – if dehydrated will overestimate the percentage of body fat Equipment is fairly expensive Determining Body Mass Index Use the persons body weight and height to calculate BMI BMI is ratio of body weight to height A BMI of 25-30 indicates that a person is overweight and a BMI over 30 equals obesity Assessing Caloric Balance Caloric balance = Number of calories consumed (–) number of calories expended If more calories are consumed than expended = weight gain If more calories are expended than consumed = weight loss Caloric Consumption or Intake Caloric balance is determined by the number of calories consumed regardless of whether the calories are contained in fat, CHO, or protein. CHO = 4 calories per gram, Protein = 4 calories per gram, Fat = 9 calories per gram, Alcohol = 7 calories per gram Estimations of caloric intake for college athletes = 2,000-5,000 calories per day Estimations of caloric expenditure range between 2,200 – 4,400 calories on average Caloric Expenditure Calories may be expended in three different processes: Basal metabolism, work (defined as any activity that requires more energy then sleeping), and excretion Specific energy expenditures can be determined by consulting charts that predict energy used in an activity based on: Time spent in each activity in minutes The metabolic costs of each activity in kilocalories per minute per pound (kcal/min/lb) of body weight Methods of Weight Loss Weight loss through dieting alone is difficult and in most cases ineffective means of weight control 35-45% of weight decrease due to dieting results in loss of lean tissue Minimum caloric intake should not go below 1,000 – 1,200 calories a day for females and 1,200 – 1,400 for males Weight loss through exercise involves an 80-90% loss of fat tissue with almost no loss of lean tissue Most efficient method of weight loss is combination of diet and exercise Goal with any weight loss program is loss of 1.5-2 pounds per week, weight loss of more than 4-5 pounds per week may be attributed to dehydration as opposed to body fat Methods of Weight Gain Aim of weight gaining program is to increase lean body mass Recommend rate of weight gain is 1-2 pounds per week To gain one pound of muscle, an excess of approximately 2,500 calories is needed, to lose one pound of fat, approximately 3,500 calories in excess of intake must be expended in activities Prentice, Principles of Athletic Training , 15e LO-5 | 8 Chapter 5 Nutrition and Supplements o Adding 500-1,000 calories a day to the usual diet will provide energy needs of gaining 12 pounds per week Weight training must be a part of the weight gaining program Disordered Eating Defined as spectrum of abnormal eating behaviors, ranging from mild food restriction and occasional binging and purging, to severe conditions of bulimia nervosa and anorexia nervosa Multi-factorial disorder includes social, familial, physiological and psychological components Screening tests are now being used to detect eating disorders Types of eating disorders Bulimia Nervosa o Commonly female ranging from adolescence to middle age o 1-2% of population will develop bulimia nervosa, anorexia nervosa or both o Typically gorges self with thousands of calories after a period of starvation and then purges self though induced vomiting and further fasting or through use of laxatives or diuretics o Typically is white, middle-upper class family, perfectionistic, obedient, overcompliant, highly motivated, successful academically, well liked by peers and a good athlete o Commonly participates in gymnastics, track and dance, males included in wrestling and gymnastics o Binge-purge patterns can cause stomach rupture, disruption of hear rhythm, liver damage, tooth decay from vomiting and chronically inflamed mucous lining of mouth and throat Anorexia Nervosa o 30-50% of individuals with anorexia nervosa will also develop some symptoms of bulimia nervosa o Characterized by distorted body image and a major concern about weight gain o 15-21% of individuals diagnosed with anorexia nervosa ultimately die from the disorder o Deny hunger, are hyperactive, engage in abnormal amounts of exercise, and are highly secretive o Getting the patient to realize they have a problem through treatment and early intervention is the key to treatment Anorexia Athletica o Condition specific to athletes characterized by several of the features common to anorexia nervosa without the self-starvation practices o Exhibit signs including: disturbance of body image, weight loss greater than 5% of body weight, gastrointestinal complaints, primary amenorrhea, menstrual dysfunction, absence of medical illness explaining the weight reduction, excessive fear of becoming obese, binging or purging, compulsive eating and/or restriction of caloric intake Female Athlete Triad Syndrome o Combination of an eating disorder (either bulimia or anorexia), amenorrhea, and osteoporosis o The major risk of this syndrome is that bone lost in osteoporosis may not be regained Prentice, Principles of Athletic Training , 15e LO-5 | 9