Lecture Summaries PDF

Lecture Summaries Monday, November 18, 2024 9:10 AM Nutrition and Metabolism Creatine - peak power during repeated 10 second efforts increased significantly Performance enhancement due to increased muscle phospho-creatine stores Increases muscle size and mass (1-2kg) over the first f...

Lecture Summaries Monday, November 18, 2024 9:10 AM Nutrition and Metabolism Creatine - peak power during repeated 10 second efforts increased significantly Performance enhancement due to increased muscle phospho-creatine stores Increases muscle size and mass (1-2kg) over the first few days due to increases in intracel Chronic supplementation combined with training enhances muscle growth ○ Super training effect due to anabolic effect of creatine ○ Increased muscle water stimulates muscle protein synthesis Carbohydrate (CHO) - high CHO intake for few days prior to exercise extends time to exhaustion and high fat diet Enhanced CHO stores in the muscle and liver If CHO stores are completely depleted it can significantly decrease performance Immediate post exercise (30-60 mins) is critical for repletion of depleted CHO stores CHO loading - increase carbohydrate intake before a competition to maximise stores that can b competition Decrease exercise time leading up to competition to prevent fatigue from inhibiting perfo CHO stores Providing CHO during exercise helps maintain blood sugar and can enhance performance Energy - increase kcal intake when training to increase / maintain energy levels Women often under eat relative to energy expenditure leading to adverse effects on perf to nutrient deficiencies Relative energy deficiency syndrome - women have significant ability to down regulate m Nutrition - intake and utilization of food and supplements (ingestion, absorption, transport, me Nutrient - substance that you consume to prevent disease and maintain health (body cannot m Macronutrient = need in gram or hundred of gram quantities (CHO, fat, protein) Micronutrient = need in milligram or microgram quantities (vitamins and minerals) Three roles of nutrients 1. Provide energy 2. Promote growth and development  llular water n compared to a normal be utilized during ormance and depleting e formance or health due metabolism etabolism and utilization) make these)  Macronutrient = need in gram or hundred of gram quantities (CHO, fat, protein) Micronutrient = need in milligram or microgram quantities (vitamins and minerals) Three roles of nutrients 1. Provide energy 2. Promote growth and development 3. Regulate metabolism Nutritional screening of athletes Dietary evaluation Biochemical testing of blood or urine Body composition analysis Clinical assessment of appearance and well-being Retrospective Techniques Dietary history - last several weeks or recall last 24 hours ○ Interviewer asks athlete to describe usual food and drink patterns ○ Several weeks is more representative but can be less accurate due to recall accurac Food frequency questionnaire - list of foods consumed in amount and frequency Limitation = techniques rely on athletes memory which is often inaccurate due to judgem altering habits to please investigator, or forgetfulness Prospective Techniques Analysis of duplicate meals - most accurate but expensive Food records - weighted or estimated for 3-7 days (best practical option) Limitations ○ Cost and equipment ○ Subjects may alter their eating patterns to please investigator ○ Insufficient documentation by subjects ○ Typically these records underestimate intake up to 20% (especially women) Nutritional Terminology RNI - recommended nutrient intake (amount of nutrients necessary to meet needs of all p ○ Recommendation is always greater than the requirement because it contains a safe for people above average ○ 2 SD above requirement will meet needs of all population RDA - recommended dietary allowance (same as RNI) DRI - dietary reference intake (newer terminology for same concepts) AI - adequate intake (estimates based on observations of healthy individuals and used wh determine RDA) UL - upper limit (intake above this limit will cause health problems) EAR - estimated average requirement (amount of nutrient that would meet needs of half ESADDI - estimated safe and adequate daily dietary intake cy ment on portion sizes, population ety buffer to compensate hen insufficient data to f the population)  AI - adequate intake (estimates based on observations of healthy individuals and used wh determine RDA) UL - upper limit (intake above this limit will cause health problems) EAR - estimated average requirement (amount of nutrient that would meet needs of half ESADDI - estimated safe and adequate daily dietary intake Balance Technique Method used to determine dietary recommendations Measurement of difference between amount of nutrient that enters body and what is ex ○ If intake > excretion = positive balance (increase body storage or growth) ○ If intake < excretion = negative balance (loss of body storage, reduction in muscle m Essential / indispensable nutrient - one that cannot be synthesized in the body and there deficiency will occur Non-essential / dispensable nutrient - one that can be synthesized in the body from othe Two Areas of Exercise Nutrition 1. Nutrient requirements ○ How does chronic exercise affect food requirements 2. Performance effects ○ Can supplementation with food or components enhance performance Ergogenic Aid - a procedure or treatment that enhances performance (can include supplements training methods, imagery) Questions to ask when evaluating a nutritional claim 1. Is there underlying rationale for how it should work 2. Is there good data to support this rationale 3. Who gains something from promotion 4. Is it too good to be true Epidemiological research - attempts to determine whether relationships exist between two var sample sizes) Useful to determine a relationship but does not identify if one is causing the other (only t Retrospective - studying past behaviour Prospective - study future behaviour Experimental research - involves an intervention in order to determine whether a cause and eff between variables Independent variable is manipulated and the effects on the dependant variable are studi Independent = x axis (horizontal) Dependant = y axis (vertical) Typically smaller sample sizes are studied Considerations when evaluating experimental research hen insufficient data to f the population) xcreted from all routes mass and size) efore be part of the diet or er compounds s, biomechanical tools, riables (involves large that they are related) fect relationship exists ied  Independent = x axis (horizontal) Dependant = y axis (vertical) Typically smaller sample sizes are studied Considerations when evaluating experimental research 1. Is there a good rationale for the proposed effect 2. Were the methods used appropriate 3. Have the results been replicated by others Canada's Food Guide Half of intake should be fruits and vegetables Milk and dairy is no longer included (only included because market pushed for it) Best recommendation is making drink of choice water Changes from 2007 guide ○ Rainbow is gone ○ Milk and alternatives food group is gone ○ Serving sizes gone ○ Increased fibre intake ○ Lower intake of processed meats and saturated fats Food Exchange System - practical system developed by diabetes association originally for diabe 6 food groups (similar within group energy and macronutrient content) ○ Starch / bread ○ Meat (very lean, lean, med fat, high fat) ○ Vegetable ○ Fruit ○ Milk (skim, low fat, whole) ○ Fat Note differences in macronutrients and energy content of different exchanges. As well as exchanges Key Nutrient Concept - including eight key nutrients that can be consumed from a wide variety diet will result in you likely receiving all essential nutrients Nutrient Density - the concentration of an essential nutrients in a food relative to the kcals Nutrient dense foods are high in nutrients and relatively low in calories Concern for vegetarian diets not being able to obtain enough nutrients Concerns with Vegetarian Diet 1. Energy - concern is that limited foods are not kcal dense 2. Vitamin B12 and D - limited foods that contain these vitamins in a vegetarian diet 3. Minerals - not absorbed well because some plant foods form compounds that bind miner unabsorbable 4. Protein - plant protein is considered incomplete so complementary proteins must be com etics s fat content between of natural foods in your rals making them mbined throughout Concerns with Vegetarian Diet 1. Energy - concern is that limited foods are not kcal dense 2. Vitamin B12 and D - limited foods that contain these vitamins in a vegetarian diet 3. Minerals - not absorbed well because some plant foods form compounds that bind miner unabsorbable 4. Protein - plant protein is considered incomplete so complementary proteins must be com different meals to consume all essential amino acids ○ If grains and seeds were only source of protein you would have just enough lysine ○ If beans and veggies were only source of protein you would get just enough methio ○ If nuts were only source of protein you would likely fall short on lysine Benefits of Plant Based Diet Low total and saturated fat High fibre and low energy High antioxidant vitamins ○ Reduce cellular aging by upregulating ability to protect from oxygen free radicals ○ Other positive health benefits Canadian Food Labels All foods require a label except the following ○ Fresh fruits and vegetables ○ Raw meat, poultry, seafood ○ Items prepared and processed in store ○ Alcoholic beverages Provide information such as serving size, core list (macronutrients), vitamins / minerals, in related health claims Labelling regulations ○ Attempt to ensure that consumers are given consistent information ○ Regulations apply to all food based on recognized health and science data ○ Forbids use of partially hydrogenated oils ○ "free" claims indicate the amount of a nutrient used is insignificant ○ Claims for saturated fatty acids now include a restriction on both saturated and tra ○ "light" claim is allowed only on foods that meet criteria for reduced fat or reduced Claims permitted about foods for children under 2 years include "source of protein", "exc "no added salt", "no added sugar" Health claims restricted to scientifically established relationship between diet and risk red ○ Sodium / potassium and high BP ○ Calcium / vitamin D and osteoporosis ○ Saturated fat / trans fat and heart disease Food Intolerance - adverse reaction but not life threatening Food Allergy - allergic reaction to food component that can result in swelling, rash, itching, anap rals making them mbined throughout onine ngredient list and any ans fatty acids in kcal cellent source of protein", duction phylactic shock and death  ○ Saturated fat / trans fat and heart disease Food Intolerance - adverse reaction but not life threatening Food Allergy - allergic reaction to food component that can result in swelling, rash, itching, anap Food Poisoning - nausea, vomiting caused by ingestion of bacteria due to poor food handling Other Food Problems Food additives are generally safe Food processing can reduce the amount of nutrients and introduce bacteria Commercial food products contain refined sugars, enriched white flour, synthetic produc Fuels Available to Muscle 1. Phosphagens (ATP and PCr) ○ Small supply for 3-5 seconds of intense exercise ○ formed oxidatively from foods ○ Can provide energy anaerobically 2. Anaerobic glycolysis ○ Provides ATP quickly but also produces lactic acid which lowers blood pH ○ Uses CHO in the form of glucose ○ Glycogenolysis = breakdown of glycogen into glucose to be used for energy 3. Oxidative phosphorylation ○ Provides much more ATP but at a slower rate because it is limited by oxygen delive ○ Use CHO, fat and protein Magnitude of Energy Stores ATP = 1 kcal PCr = 4 kcal CHO = 2000 kcal Protein = 30 000 kcal Fat = 100 000+ kcal Anabolic (tissue building processes) Digestion - complex compounds are broken down into simple compounds (ex. CHO into s amino acids) Absorption - nutrients converted to complex compounds to be stored for later use (ex. sim glycogen) Catabolic (mobilizing stored energy to fuel muscle contraction) ATP and PCR stores, anaerobic glycolysis, oxidative phosphorylation Pathway used depends on rate of ATP needed (determined by exercise intensity) Metabolism - all physical and chemical transformations in the body phylactic shock and death cts ery simple sugar, protein into mple sugars into Catabolic (mobilizing stored energy to fuel muscle contraction) ATP and PCR stores, anaerobic glycolysis, oxidative phosphorylation Pathway used depends on rate of ATP needed (determined by exercise intensity) Metabolism - all physical and chemical transformations in the body Catabolic = growth Anabolic = wasting Metabolic rate is the measure of how rapidly the body is using it stored energy Total daily energy expenditure (TDEE) - metabolic rate expressed for one day Resting energy expenditure Food intake Physical activity Resting metabolic rate (RMR) or resting energy expenditure (REE) Rate is related to muscle mass Factors include age, gender, fitness, weight loss, low energy diets, caffeine, smoking and temperature 65-70% of TDEE Dietary induced thermogenesis (DIT) or thermic effect of food (TEF) Increases due to digestion, absorption and storage of energy following food intake 1-4 hours following a meal (8-10% increase) Magnitude depends on amount and type of food 5-10% of TDEE Thermic effect of exercise (TEE) Increases due to physical activity and can vary substantially 15-30% of TDEE Measured as litres of oxygen (VO2), METS (10-20x RMR) Estimated using HR, ventilation, onset of blood lactate accumulation, perceived exertion Low intensity exercise - fuel is from fat due to the vast energy storage we have, fatigue is deter or dehydration Moderate intensity exercise - more reliance on CHO for fuel due to higher intensity requiring O to glycogen depletion, hypoglycemia or dehydration Maximal intensity exercise - fatigue due to PCr depletion (inability to regenerate quickly enough Protein as a fuel source Only provides auxiliary fuel source for prolonged exercise Amino acids are primarily used for tissue growth and repair after exercise  environmental rmined by hypoglycemia O2 delivery, fatigue is due h) Maximal intensity exercise - fatigue due to PCr depletion (inability to regenerate quickly enough Protein as a fuel source Only provides auxiliary fuel source for prolonged exercise Amino acids are primarily used for tissue growth and repair after exercise Carbohydrates Carbohydrates - organic compounds made of carbon, hydrogen and oxygen Simple CHO ○ Disaccharides: maltose, lactose, sucrose ○ Monosaccharides: glucose, fructose, galactose Complex CHO ○ Oligosaccharide: 3 to 9 glucose molecules ○ Polysaccharide: 10 or more glucose molecules ○ Starches § Amylopectin which is digested and absorbed rapidly § Amylose which is digested and absorbed slowly ○ Fiber § Polysaccharides in plants that are resistant to digestive enzymes § Some water soluble, some not § Increase satiety ○ Glycogen § In animal muscle and liver § Large branched molecule Glycemic Index - numerical system ranking foods based on the rise in circulating blood sugar (o the blood) Assumes 50g of CHO per serving 70 high Limitation is that it does not consider how much CHO is in a serving of food which varies s Is a better classification system than simple/complex CHO because both sugars and starch glycemic index Rebound hypoglycemia = low blood glucose shortly after intake of high glycemic food as a insulin Glycemic Load - assesses the actual impact of CHO consumption by considering both glucose en amount of CHO in serving 20 high  h) or the rate of entry into substantially hes can have high a result of effect of ntry speed into blood and Glycemic Load - assesses the actual impact of CHO consumption by considering both glucose en amount of CHO in serving 20 high Low glycemic load: all bran cereal, apples, carrots, chick peas, oranges, peaches, peanuts beets, pineapple, popcorn, watermelon, whole wheat flour Medium glycemic load: bananas, fruit juice, sweet potato, sourdough bread, cheerios High glycemic load: linguine, macaroni, white rice, russet potato, cornflakes Is best option because it indicates both rate of entry of glucose into bloodstream and how particular foods Body CHO stores Blood Liver (glucose from glycogen release into the blood) ○ 50% depleted overnight Muscle (largest store) ○ Hypoglycemia adversely affects performance ○ Can be depleted in a single exercise bout Gluconeogenesis - formation of new glucose molecules that occurs in the liver Functions of CHO Major energy source for the brain, CNS and exercising muscle (especially at high intensitie Combined with fat or protein they form important components of cell membranes (glyco Form smaller CHO compounds which are involved in muscle growth CHO Loading (supercompensation) Important because body CHO stores are limited and can be exhausted in one exercise bo Is beneficial for continuous exercise at moderate to high intensity Procedure involves tapering exercise training and increasing dietary CHO leading up to co Adequate intake is at least 5 g/kg but 8-10 g/kg is desirable (should be a mixture of low a Will increase body weight because every gram of CHO is stored with three grams of wate converted to glycogen Females may be less able to CHO load due to less reliance on CHO during exercise Timing of CHO Intake 1-4 hours prior to exercise ○ 4-5 g/kg ○ Variety of forms (fluids containing simple sugars or solid CHO like fruit or starches)