EDGU1003 Notes: History of Sports Nutrition PDF

EDGU1003 NOTES HISTORY OF SPORTS NUTRITION ★​ Nutrition known to play a role in performance as early as Ancient Greece ★​ Roman gladiators diet→ high in carbs (breads + stewed legumes) to fuel for battles/cheaper meals ★​ Mid 18th C (1747) → Dr James Lind first scientific experiment in nutrit...

EDGU1003 NOTES HISTORY OF SPORTS NUTRITION ★​ Nutrition known to play a role in performance as early as Ancient Greece ★​ Roman gladiators diet→ high in carbs (breads + stewed legumes) to fuel for battles/cheaper meals ★​ Mid 18th C (1747) → Dr James Lind first scientific experiment in nutrition → citrus can prevent scurvy ★​ Late 18th C (1770) → Antoine Lavoisier discovered process of metabolism, equation w/ combo of food + oxygen in body and release of heat + water ★​ Early 19th C (1801) → foods composed of carbon, nitrogen, hydrogen, + oxygen ○​ Methods developed to determine amt of elements in food ★​ Mid 19th C, Justus Von Liebig 1842→ primary fuel for muscular contractions is protein ○​ 2 decades later, this view opposed by idea that carbs + fat played role in contracting skeletal muscle ★​ Early 20th C (1912) → Dr Casmir Funk coined “vitamins” as vital factors in diet ★​ Mid 20th C (1950s + 1960s) → improvement of investigating nutritional sciences using isotopes + muscle biopsies which measured muscle glycogen (more accurate), increased investigation of muscle glycogen storage ★​ Mid - late 20th C → role of nutrients as part of bodily processes discovered, e.g. vitamins + minerals are critical components of enzymes + hormones ★​ Early 21st C→ known that carbs required for high intensity exercise, during exercise of 80% VO2 max or higher, fat oxidation reduced or negligible ○​ Fat oxidation → use of fat as fuel, increases after 10-12 weeks of lower intensity endurance training ○​ Increase in popularity + availability of processed foods = obesity + chronic disease  ○​ Diet nutrition for sport advantage→ dietary variants e.g. supplements, optimal eating before events, etc. ★​ Nutritional science incomplete due to personal biases, diff research methods, contradictory studies NUTRITION OVERVIEW ★​ Factors influencing food choices: ○​ Emotional comfort ○​ Environmental concerns ○​ Social→ gatherings, special events, holidays, customs ○​ Nutritional value ○​ Personal preference ○​ Habitual patterns→ culture, tradition, religion ○​ Food marketing→ e.g. Maccas in sporting tournaments ○​ Availability, convenience, cot ○​ Physical/health enhancement ○​ Routine ○​ Physiological influences→ hunger + appetite related to ghrelin + leptin hormones, age, gender, genetics ​ Satiety level of foods based on their macronutrient composition ★​ Factors of health: ○​ Physical→ injury/disease free, endurance, strength, physical processes in body, body systems, hormones (e.g. ghrelin + leptin control hunger levels) ○​ Social→ healthy relationships ○​ Emotional→ health of mind, thoughts + feelings ○​ Spiritual→ sense of purpose in life stemming from work, religion, family etc. ○​ Intellectual→ mental stimulation, learning etc. ○​ Environmental  ★​ Spectrum of nutrients: carbs, fats, proteins, vitamins, minerals, + water ○​ Essential for growth, sustenance, + repair of body tissues ○​ Chemical structure from both organic (carbon-containing) + inorganic compounds ★​ Essential nutrients→ cannot be synthesised by body/cannot be produced in sufficient amounts, obtained from diet ★​ Non-essential nutrients→ synthesised by body or is not required for survival ★​ Requirement for health is continuous replenishment of nutrients energy from diet ★​ Nutrients may be energy yielding (provides body with required energy), measured in kJ or calories (energy content/gram) ○​ Energy yielding nutrients: carbs, fats, + proteins aka MACRONUTRIENTS (required in large quantities) ​ Carbs + proteins = 17 kJ/g ​ Fat = 37 kJ/g → “energy dense” ○​ Non energy-yielding: vitamins + minerals → do not directly provide energy by vital in absorption of macronutrients aka MICRONUTRIENTS ★​ Metabolism→ breaking down of food into energy, where excess energy is stored as body fat ★​ Vitamins→ organic, essential nutrients that enable body to extract energy from macronutrients ★​ Minerals→ inorganic, located in bones, teeth, + bodily fluid ★​ Poor diet increases risk factors for chronic disease NUTRITION + CHRONIC DISEASE ★​ Short term benefits of good nutrition (i.e. 24 hrs-1 week): energy, digestion, focus, improved sleep patterns + mood, clear skin, strong nails etc. ★​ Long term benefits of poor nutrition: chronic illnesses e.g. gout, haemorrhoids, cancer, HBP ★​ CANCER + NUTRITION: ○​ Increased risk of cancer especially in organs of digestive tract (e.g. mouth, tongue, esophageal tract, stomach, colon) ○​ Prevention: Risk increased by consumption of carcinogenic compounds (aka HCA/heterocyclic amines, e.g. black charring) which may proliferate, + repeated exposure to pathogens or food (e.g. caused by GORD, results in gastric ulcers, cells can mutate into cancer) ○​ Treatment: poor appetite = cachexia (weight + muscle loss), lower protein consumption, loss of taste, N+V, poor appetite ○​ Recovery: recovery of muscle mass ★​ NUTRITION + HEART HEALTH: ○​ Mediterranean diet associated w/ good heart health: ​ Whole foods, limited processed foods ​ a-Linolenic acid→ type of omega-3 fatty acid, from fatty fish, walnuts, chia seeds, flaxseed etc ○​ Fruit + veg: contains phytochemicals (plant-based bioactive compounds for protection, e.g. carotenoids, curcumin) = antioxidant, high amts of fibre = digestion, prevent oxidative damage ○​ Soy: isoflavones (antioxidants = antinflammatory), proteins, lowering blood lipids = antithrombotic, decreases platelet aggregation = less artery + vein blockage, increased vascular elasticity ​ Some correlation w/ increased estrogen + cancers ○​ Wholegrains: large amt of soluble fibre decreases serum + LDL cholesterol ​ Low GI (carbs that are converted into sugar released at slower rate = longer-lasting form of energy to prevent sugar + insulin spike, vs high GI foods which can cause insulin resistance, linked to coronary heart disease) → improves BGLs + hypertension ​ Contains gluten→ protein found in wheat, rye, + barley, associated w/ inflammatory effects (e.g. gluten ataxia, celiac disease)  ​ Gluten ataxia→ autoimmune disorder, antibodies released during gluten digestion attacks brain = movement issues, loss of balance, slurred speech etc. ★​ GUT DISORDERS + NUTRITION: ○​ IBD→ diff from IBS, refers to Crohn's disease (anywhere in digestive tract) or ulcerative colitis (large intestine), both involved inflammation of lower digestive tract, causes pain, diarrhoea, weight loss + fever ​ Occurs 1/7 ppl ​ Treatments: ​ Eliminate trigger foods ​ Omega-3 fatty acids are anti-inflammatory ​ Reduce gastric stimulants, e.g caffeine creamy foods, chilli, garlic ​ Whole food diets best, but toxins in plants may increase symptoms ○​ Diverticulosis→ formation of abnormal pouches in bowel lining ​ Symptoms: pain in abdomen, bloating, bloody stool, poor bowel habits, indigestion, N+V ​ Diverticulitis→ inflammation/infection of pouches ​ Treatment: ​ Chew food ​ Lower intake of small foods ​ Simple foods ​ Identify + eliminate trigger foods ★​ GUT DISORDERS + EYESIGHT ○​ E.g. macular degeneration (caused by reduced blood flow to eyes) → reduce blood lipid levels, increase antioxidants ADG & AGHE ★​ Australian Dietary Guidelines→ provides information about dietary patterns + serving sizes to promote health, reduce risk of diet-related conditions (high cholesterol, HBP, obesity), and reduce risk of chronic disease (T2D, CVD, cancer) ○​ Based on latest scientific evidence ○​ Provides suggestions for discretionary foods ○​ Designed for use by health professionals, policy makers, educators, food manufacturers, retailers, + researchers ○​ Applicable to all healthy Australians, not those w/ special dietary advice for medical conditions or elderly ○​ Avg aus diet contains: too much alcohol, sat fats, sodium, sugar, and insufficient fibre, wholegrains, legumes, fruits, + veg ○​ Guideline 1: be physically active, choose nutritious foods, stay hydrated ○​ 2: eat from all 5 food groups ○​ 3: limit intake of foods w/ saturated fats, added salt, sugars, + alcohol ○​ 4: encourage breastfeeding ○​ 5: care, prepare, + store food safely ★​ Australian Guide to Healthy Eating→ food selection guide providing visual representation of proportion of five food groups: ○​ 1. Vegetables and legumes ○​ 2. Fruit ○​ 3. Grains (cereal foods) ○​ 4. Meat, fish, poultry, eggs, legumes, nuts, tofu ○​ 5. Milk, yogurt, cheese, alternatives + allowance for fats and oils ○​ Increasing nutritional quality of diet: wholegrains, plant + animal based protein, reduced fat dairy ○​ Also includes small amts of fats + oils + discretionary foods  ★​ Types of guidelines: pyramids + pies from Nutrition Australia in 1990s (3 sections based on amount to eat), AGHE 1998 (5 food groups + includes fluids), AGHE 2013 (designed to emphasise fresh, whole foods over supplementation), Japanese spinning top food guide DIGESTION, ABSORPTION, + TRANSPORT ★​ Monogastric: one stomach ★​ Digestion: complex process of breaking down food into nutrients for absorption ★​ Involves enzymes specific to each nutrient ★​ Food breakdown takes 2-72 hrs ★​ Mouth→oesophagus→ stomach→ small intestine→ pancreas→ gallbladder→ liver→ appendix→ large intestine 1.​ Mouth: mechanical digestion (food broken into smaller pieces), chemical digestion (amylase in saliva breaks down starches), saliva moistens + softens food -​ Stimulation of taste buds increases saliva production -​ Bolus: ball of food + saliva -​ Flap of tissue called epiglottis seals off trachea, prevents entering pharynx (junction b/w digestive + resp system) 2.​ Oesophagus: peristalsis→ smooth, involuntary muscle contractions push food down 3.​ Stomach: food entrance + exit controlled by sphincters (ring-shaped muscle that relaxes + tightens), mechanical (churned) + chemical (food turned into acidic liquid called chyme by pepsin to break down proteins and HCl to kill bacteria) 4.​ Small intestine: chyme (partially digested food) enters narrow small intestine, mixes w/ digestive juices from other organs, + squirted into duodenum by peristalsis for nutrient absorption, lined w/ villi (small hair-like projections filled w/ blood vessels) → increases SA, transports nutrients to body via blood stream -​ Duodenum, jejunum, ileum  5.​ Pancreas: non-essential pistol-shaped organ + located behind stomach, secretes digestive enzymes + hormones into duodenum e.g. lipases, proteases, amylases (breaks carbs), sodium bicarbonate, insulin, + glucagon 6.​ Gallbladder: pear-shaped muscular sac on underside of liver that stores + concentrates bile (greenish-yellow, slightly acidic) which breaks down fat -​ Gallstones form from cholesterol crystallising into stone-like material 7.​ Liver: wedge-shaped, spongy organ below diaphragm, rids body of toxins, regulated BGL, produces bile + cholesterol -​ 60% liver tissue are hepatic cells, also Kupffer cells (macrophages) 8.​ Appendix: unknown role in digestion, was thought to break down tree bark + tough foods, some evidence that appendix helps fight infections -​ Appendicitis: blockage of appendix where it joins large intestine 9.​ Large intestine: last part of tract, 1.5 m long which converts food waste into faeces → water absorbed + undigested food, waste, + fibre eliminated ★​ Bristol Stool Chart is guide for gut health ★​ Factors influencing digestion: ○​ Caffeine consumption ○​ Fat + fibre intake ○​ Hydration ○​ Stress ○​ Exercise ○​ Artificial sweeteners (may speed up digestive process = loose stool) FOOD & ENERGY ★​ Energy→ fuel that confers ability to do work ○​ Hydro, thermal, electrical, + chemical ★​ Chemical energy→ obtained from food digestion + used to produce ATP  ○​ Chemical bonds b/w nutrients broken + releases adenosine triphosphate (ATP) ★​ ATP→ powers cellular processes by transferring phosphate group to another molecule (phosphorylation) in the presence of enzymes, releasing energy from ATP ★​ Energy metabolism→ sum of all chemical reactions occurring in living cells– e.g. cell repair/growth, conversion of food - energy, glycolysis (glucose broken into two pyruvate, then oxidised to acetyl-CoA which enters Krebs cycle to form energy in form of ATP) ○​ Anabolic→ formation of larger compounds from smaller molecules, requiring energy– e.g. bone development, muscle mass gain, glycogen synthesis ○​ Catabolic→ breaking down of larger compounds into smaller ones, releasing energy– e.g. food digestion, breakdown of glycogen into glucose during low-energy availability ○​ Three main processes of energy metabolism: energy intake, energy expenditure, + energy storage ★​ Energy intake→ energy obtained from consuming food + drink (carbs, protein, fat, alcohol) ○​ Measured in kJ or cal: 1 cal = 4.18 kJ ○​ 4.18 kJ is energy required to heat up 1L water by 1 degree ○​ Fat = 37kJ/g (most energy dense) ○​ Alcohol = 29kJ/g ○​ Carbs + proteins = 7kJ/g ★​ Energy expenditure (EE)→ kJ burned daily, composed of basal metabolism, diet-induced thermogenesis, activity-induced thermogenesis ○​ Basal metabolism: energy req to maintain life at rest, includes all physiological processes performed at rest ​ Basal metabolic rate (BMR) → energy req to sustain basal metabolism, 60-70% total energy expenditure. Influenced by age, gender, genetics, + body composition  ​ Body composition is the most significant factor→ amount of lean body mass. More muscle mass + higher lean body mass = higher BMR ○​ Diet induced thermogenesis/thermic effect of food (TEF)→ energy required for body to digest, absorb, + metabolise food, 10% of total energy expenditure ​ Thermic effect of macronutrients varies ​ Protein has highest thermic effect ○​ Activity-induced thermogenesis ​ Exercise→ additional energy req for physical activity– 5% of total EE, up to 15-30% EE in athletes ​ Non-exercise→ all basic movements, e.g. postural muscles for standing– 5-10% total EE, up to 50% in ppl performing very physical work ★​ Energy storage→ When energy intake exceeds requirement, excess energy stored as glycogen in skeletal muscles + liver, and when glycogen stores are full, excess energy is stored as fat in adipose cells found between the skin and muscle, in the form of triglycerides ★​ Energy surplus→ created when excess calories (more than is expended or required) are consumed MACRONUTRIENTS ★​ Monogastric: one stomach ★​ Digestion: complex process of breaking down food into nutrients for absorption ★​ Involves enzymes specific CARBS ★​ Carbohydrate→ biomolecule that is essential in the human diet, providing energy in form of glucose + storing energy in the form of glycogen (mostly in muscle tissue + liver) ○​ Types: sugars, starches, dietary fibre, found in all plant foods, wholegrains, veg, legumes, fruits, + milk products ○​ Used to build macromolecules ○​ Carb availability spares protein + fat for other uses ○​ Provides nearly all energy required by brain for daily use ○​ Structure of carb influences how body digests + metabolises it ○​ Glycogen: stored form of carbs, provides half of energy used by muscle + body tissues (other half from fat) ★​ Simple carbs: ○​ Monosaccharides: single sugars, differing in molecular arrangements + sweetness levels ​ Glucose: primary energy source, aka dextrose ​ Fructose: sweetest sugar, naturally in honey + fruits ​ Galactose: rarely occurs naturally as single sugar ○​ Disaccharides: pairs of monosaccharides where one is always glucose, linked through condensation reactions + split by hydrolysis ​ Maltose (gluc + gluc): produced during seed germination + fermentation ​ Sucrose (gluc + fruc): refined from sugar cane + sugar beets, tastes sweet ​ Lactose (gluc + galac): milk + milk products ★​ Complex carbs: derived from few (oligosaccharides) or many (polysaccharides) glucose units linked in straight/branched chains ○​ Glycogen: storage form of glucose, provides rapid energy release when req  ○​ Starches: storage form of glucose in plants, found in grains, tubers, + legumes ○​ Dietary fibre: provides structure in plants + cannot be broken by human enzymes ★​ CARB DIGESTION + ABSORPTION: ○​ Starch + sugar broken to dextrins (short glucose chains) → broken to monosaccharides, then glucose used for energy ○​ Glucose absorption slowed by dietary fibre which regulates passage of food thru GI tract ○​ Carb digestion starts in mouth→ amylase hydrolyses starch into short polysaccharides + maltose ○​ Stomach acid hydrolyses starch while dietary fibre delays gastric emptying ○​ Carb absorption in small intestine, pancreatic amylase + maltase, sucrase, + lactase hydrolyses starch to disaccharides + monosaccharides ○​ Dietary fibres attract water, soften stools, + ferment ★​ CARB METABOLISM: ○​ Gluconeogenesis→ formation of glucose from protein when glycogen stores are depleted ○​ Protein-sparing→ having adequate carbs in diet to prevent breakdown of protein for energy ○​ Glucose homeostasis essential as low BGL = dizziness + weakness, high BGL = fatigue ○​ Hormones in glucose homeostasis + regulation: ​ Insulin→ encourages glucose uptake into cells + lowers BGL ​ Glucagon→ brings glucose from storage + raises BGL ​ Epinephrine→ facilitates rapid glucose mobilisation during times of stress  ★​ Ketosis→ when carb supplies low, fat sources used for energy when body is in state of ketosis – accumulation of ketone bodies in blood, formed from fat fragments, which act as alternative form of fuel ★​ Glycaemic Index (GI) → number b/w 1-100, determines how easily body can digest components of the food + how quickly an increase in BGL can be expected following consumption ○​ Low GI < 55 = slower raise in BGL = full longer ○​ Medium GI = 56 - 69 ○​ High GI > 70 ○​ Glycaemic load→ carb content of food, hence protein + fat have minimal influence over GI ★​ Glycaemic response→ how quickly BGL rises + elicits an insulin response ★​ BGL→ classifies foods according to potential for raising BGL ○​ high GI carbs cause spike in BGL, then drastic drop while low GI are digested + absorbed slowly for sustained energy ○​ When BGL out of range, hypoglycemia (low BGL) or hyperglycemia ○​ T1D = body doesn’t prod enough insulin ○​ T2D = diagnosed when BGL too high as insulin produced by pancreas does not work effectively (aka insulin resistance) ​ Usually adults over 45, now increasing in younger age groups due to poor diet + lack of physical activity ​ Progressive, requires oral meds and/or insulin injections SUGARS ★​ Sugar→ sweet crystalline substance obtained from various plants, simple carbs that provide quick energy ★​ Most common: white sugar (sucrose) + high fructose corn syrup ★​ Most sugar in diet from added sugar ★​ Too much sugar→ tooth decay, depression, dementia, cognitive disease, insulin resistance ★​ WHO recommends reducing sugar to