Nutrition related to fitness and sports exam 1
Terms
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- Quantitative research
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collect numerical data (statistics)
Numerical division - Qualitative research
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formative or exploratory, data collection with oberservations, interviews, etc.
Purpose division - Grounded theory research
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collects observations from real-life situations to develop theoretical propositions
Qualitative - Basic research
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not done with a specific goal, pursued to increase a body of knowledge and explore the unknown
NOT used in sports nutrition
Type division - Applied research
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takes known information and attempts to solve problems or rework existing concepts or information, used to support decision making
Type division - Descriptive research
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describe the status at a given time, useful in hypothesis generation, provides baseline data, monitors change over time and establishes associations
Purpose division - focus group
- people are assembled as a group to answer questions ona specific topic
- delphi technique
- panel of experts separately answer questions, judgement or answers are circulated to other panel members, general consensus is the goal
- Case reports
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report of observation of one subject, describes quantitatively the experience of a condition or disease, helps generate a hypothesis
descriptive research (purpose division) - Case series
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expansion of case report, observations of more than one subject
descriptive (purpose division) - Survey research
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describe and quanitify characteristics of a defined population, statistical profile of population, useful for establishing association and baseline data, based on a probability design from questionnaires, interviews, examination
descriptive (purpose division) - analytical research
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test hypotheses, detect causal association, provide proof of cause or effect
purpose division - experimental
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all factors are held constant except test variable
clinical trials
analytical (purpose division) - not experimental
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observation
cohort or follow up designed to mimic clinical trial, not experimental, testa hypothsis, therefore analytical
analytical (purpose division) - Cross sectional research
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based on data collected on a group of subjects at a singe time; now and then
Time dimension division - time series research
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consists of observations across time of a single group or across groups at a single time, useful in identifying and tracking trends
time dimension division - longitudinal research
- follows the same sample group over a prolonged period, baseline measurements are amde at the beginning of the study and other measurements are taken later or at various intervals
- prospective study
- begins with presumed causes and goes forward in ime to presumed effects, begins with belief that a particular behavior or variable will create a particular cause
- retrospective study
- begins with manifestation of an outcome and goes back in gime to uncover relationships with presumed causes
- 24 hr dietary recall
- interviewer asks the subject to recall all foods eaten and portions consumed during 24 hours of the previous day
- Food record/diary
- subject keeps a food diary for one or more days; records time, names, and quantities of foods consumed; records can be weighed, measured, or estimated
- Weighed/measured food intake
- subject or interviewer weighs and measures food portions prior to consumption by the subject, written record of food descriptions and portion sizes is kept for one day or longer, portion sizes are more accurately weight than food record/diary
- Diet history
- open-ended questionnaire, concerns food use, preparation, portion sizes, food likes and dislikes, usually includes a 24 hour diet recall and/or food frequency
- Diet frequency
- quantitative or non-quantitative, self-administered questionnaire, consists of a list of food for which the respondent indicates frequency of consumption on a daily, weekly, monthly, or yearly basis
- duplicate portions
- subject places exact duplicates of the food consumed into a receptacle for one or more days, food are then homogenized and analyzed for nutrients or contaminants
- household (family) food intake disappearance data
- foods that are used in a 1 week time period in a household, corrected for food purchases, food gifts, food waste, consumption of household food by guests or animals. results are divided by the number of persons in the household and expresses as food commodities consumed per person per day
- food availability disappearance data
- data on nation food production and food imports, corrected for food exports, waste, storage, and non-human food use; results are expressed as availability of food commodities per person per day
- Glycogenolysis
- Energy pathway where glycogen is broken down into glucose, occurs in the cytoplasm of the cell
- Epinephrine
- stimuli for glycolysis, adrenal hormone that acts at the cell surface which triggers an increase in cycly AMP which promotes a series of reaction that eventually cause glycogen breakdown in both muscle and liver
- glucagon
- released when blood glucose is low from alpha cells in pancreas and affects the liver
- glycogen phosphorylase
- enzyme that promotes the breaking of alpha 1-4 glycosidic bonds in glycogen
- debranching enzyme
- enzyme taht promotes breaking of alpha 1-6 glycosidic bonds
- glycogenolysis begins and ends with...
- glycogen and glucose 6 PO4 (to go on to glycolysis) and glucose 1 PO4 (to raise blood sugar)
- glycolysis
- breakdown of glucose into ATP. Glucose 6 PO4 is split to yeil 2 pyruvate or 2 lactate. glucose needs to be phosphorylated to begin the pathway, takes place in the cytoplasm
- Phosphofructokinase
- PFK: rate controlling enzyme for glycolysis
- Anaerobic glycolysis
- glucose is converted to lactic acid with cocommitant production of ATP. When oxygen is available, lactic acid will be reconverted to pyruvate and used as energy
- Aerobic glycolysis
- glucose is converted to 2 pyruvate with is then converted to acetyl CoA to be sent into the Kreb's cycle
- Kreb's cycle
- series of reactions that oxidize a part of acetyl CoA, carbon dioxide is produced with concomitant generation of 3 NADH, 1 FADH2, and 1 GTP
- Acetyle CoA
- enters kreb's cyle which occurs in the mitochondrion of the cell
- NADH
- yields three ATP's in elctron transport chain
- FADH2
- yields 2 ATP's in ETC
- GTP
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yields 1 ATP
GTP and ATP are rapidly interconverted - Electron transport chain-oxidative phosphorylation
- NADH and FADH2 enter the ETC and a sequence of electron transfers help drives the phosphorylation of ADP to form ATP
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Phosphagen systems:
ATP-PC -
anaerobic process, provides ATP primarily for short-term, high intensity activities (weight training, sprinting), active at the start of all exercise regardless of intensity
ADP + Creatine Phosphate --> ATP + creatine
Enzyme: creatine kinase -
Phosphagen systems:
Myokinase reaction -
anaerobic process, provides ATP for short-term high intensity activities
2 ADP --> ATP + AMP
Enzyme: myokinase
AMP also stimulates glycolysis - Lactic acid system
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anaerobic or fast glycolysis forms lactic acid from pyruvate
Lactic acid can accumulate (possible contribution to fatigue) - Gluconeogenesis
- lactic can be converted to lactate by buffering systems in the muscle and blood. This lactate can be used as energ via gluconeogenesis: formation of glucose from lactate and non-carbohydrate sources
- Oxygen system
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stimulated with longer duration type of exercise, major producer of ATP, can involve aerobic glycolysis, Kreb's cycle, and ECT-oxidative phosphorylation
Can utilize acetyl CoA from fat degradation
*beta-oxidation: biochemical pathway for fatty acids to be broken down to acetyl CoAd - Direct calorimetry
- chamber is large enough for a person and body heat is measured by change in surrounding water temperature
- Indirect calorimtry
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small portable instrument (metabolator) that measures the exchange of gases during respiration
RQ= CO2/O2 (respiratory quotient: CO2 coming off vs O2 consumed)
RQ fat=.7
RQ protein=.82
RQ carbohydrate=1.0 (most efficient)
oxidation of each carbon atom in the molecule requires one molecule of respiratory oxygen - Estimated energy requirement
- level of energy intake of food which will balance energy expenditure when the individual has a body size and composition and level of physical activity consisten with long-term good health
- TDEE
- total daily energy expenditure, sum of BEE, TEF, TEE
- BMR
- basal metabolic rate, energy requirements of necessary physiological activities in a resting post absorptive state
- BEE
- basal energy expenditure, represents the BMR over a 24 hour period
- RMR
- resting metabolic rate, represents BMR plus residual effect of food and previous muscle activity
- REE
- resting energy expenditure, energy processes over 24 hours
- TEF
- thermic effect of food, elevation of metabolic rate that occurs after ingestion of a meal
- EMR
- exercise metabolic rate, represents increase in metabolism brought about by moderate or strenuous physical activity
- TEE
- thermic effect of exercise, just another name for EMR
- PAL
- physical activity level, illustrates the effect of physical activity
- EER
- estimated energy requirements, dietary intake that is predicted to maintain energy balance in a healthy adult of a defined age, gender, weight, height, and level of physical activity consistent with good health
- DRI
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dietary reference intakes, energy is required to sustain the body's various function, including respiration, circulation, physical owrk, and maintenance of core body temperature.
DRI's will replace RDA's to show a shift in emphasis from preventing deficiency to decreasing the risk of chronic diseases through nutrition - EAR
- Estimated average requirement, nutrient intake value that is estimated to meet the needs of 50% of the population
- RDA
- recommended dietary allowance, this is the average dietary intake level of a nutrient that prevents a deficiency in 98% of a population
- AI
- adequate intake, this value is set as a goal for individual intake for nutrients, but does not have a RDA
- UL
- Tolerable upper Intake Level, this is the highest level of a nutrient that is likely to pose NO risk of adverse health effects in 98% of the population
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Activity factors for
Resting
Very Light
Light
Moderate
Heavy -
1
1.5
2.5
5.0
7.0 - Simple carbohydrates
- monsaccharides (glucose, fructose, galactose) and disaccharides (sucrose, lactose, maltose)
- Complex carbohydrates
- polysaccharides and fiber
- Starch
-
amylose- coiled linear structure
amylopectin- branched chain
resistant starch- carbohydrate that is not absorbed in the small intestine but can be fermented to short chain fatty acids in the large intestine and eventually absorbed (5-10% of the energy requirements) - Glucose polymers
- commercially prepared chain of glucose molecules
- glycogen
- storage form of glucose in the muscle and liver
- Fiber
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Dietary: fibers taht occur naturally in plants
Functional: fibers that have been extracted from plants or manufactured for their beneficial health effects
Fibers can be both dietary and functional - Glycemic index
- determined by the rate at which CHO is made available to intestinal enzymes for hydrolysis and intestinal absorption
- Factors affecting GI
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Physical availability of sugar or starch to hydrolytic enzymes: less available lower GI
Cooking: higher GI
Amylose/amylopectin: more amylopectin higher GI
Fiber content: high fiber low GI
Protein and Fat: lower GI - Glycemic load
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multiply GI by grams of CHO and divide by 100
another term to describe the way body used glucose - High GI
- bagel, bread, candy, carrots, corn flakes, corn syrup, crackers, honey, potatoes, raisins, soda, sports drinks, sucrose
- Medium GI
- all bran cereal, baked beans, corn, grapes, oatmea, orange juice, pasta, potato chips, rice, long grain rice, spaghetti, whole grain rye bread, yams
- Low GI
- apple, applesauce, cherries, chickpeas, figs, dates, fructose, ice cream, kidney beans, lentils, skim milk, navy beans, peaches, plums, tomato soup, yogurt
- CHO stores in the liver
- 75-100 grams: 400 Cal
- CHO stores in the muscles
- 300-400 grams: 1200-1600
- glycogenesis
- how glucose is converted glycogen
- Required conditions for for glycogenesis
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fed state
presence of insulin
presence of glycogen synthase
presence of branching enzyme - Insulin
- secreted by beta cells in the pancrea, stimulated by increased levels of glucose and amino acids, decreases blood glucose, increases cell permeability, inhibits glycogenolysis, promotes glycogenesis
- Glycogen synthase
- enzyme that helps the transfer of glucose to a glycogen chain
- branching enzyme
- creates branches in glycogen chain
- glycogen supercompensation
- depleted CHO stores and then storing as much glycogen as possible
- Potential foods to support energy needs during exercise
- variety of foods: combination of CHO, protein, fat, emphasis on CHO, fruit, vegetables, starch/bread, and milk exchange, personal choice and initial assessment very important
- Carbohydrate supplementation four hours before exercise
- before and during recommended especially for long endurance lasting 90 minutes
- CHO less than 1 hour before
- if prone to hypoglycemia avoid high GI food right before, sometimes using liquid is better so don't get as full
- Immediately before exercise
- normally not helpful to performance however prolonged exercise at 60-75 VO2 max
- During exercise
- major support; can help performance
- Very high intensity for less than 30 minutes
- supplementation will not enhance performance (unless reloading depleted muscle or liver glycogen)
- Very high-intensity resistance exercise training
- may use considerable amounts of muscle glycogen --> fatigue and strength loss, probably does not enhance endurance
- High-intensity exercise for 30-90 minutes
- with adequate muscle and liver glycogen CHO supplements do not improve exercise performance
- intermittent high-intensity exercise for 60-90 minutes
- soccer, ice hockey, tennis, may enhance performance if taken before and during a game
- High to moderate-intensity exercise greater than 90 minutes
- research supports a beneficial effect of CHO intake on exercise greater than 90 minutes