Sports Nutrition
Creatine
Creatine is a naturally occurring compound found in large amounts in skeletal muscle and brain as a result of dietary intake and endogenous synthesis from amino acids. Dietary intake from animal muscle (e.g. meat, fish) is 1-2 g/d or half the daily turnover. May be useful for improving performance of short duration, high-intensity exercise (sprinting, weight lifting) some studies suggest improvement in muscle strength and size, cell hydration and glycogen loading capacity Preliminary studies (Benton et al 2011) show potential cognitive benefit Effects are based on building energy stores of Phosphocreatine (PCr)— an important source of energy in the initial seconds of maximal anaerobic exertion Dose and supplement protocol Loading phase: 20g per day over 5 days (4 doses of 5g) Maintenance phase: 3g per day Taking creatine with 70-100g of CHO will enhance creatine uptake and storage within the muscle 600-1000g of weight gain is typical with loading Concerns/side effects Weight gain associated with supplementation may be counterproductive to some athletes Long term consequences are unknown and few adverse outcomes have been reported over 20 years Some individuals experience GI discomfort or headaches Supplementation should be limited to experienced and well developed athletes
Fluid replacement during
...Practice hydration plan in training and determine how much an athlete can tolerate Use a beverage that is cool (15-20°C), palatable and provides CHO Is important the athlete like the taste of their drink otherwise hydration will be comprised Begin drinking early and take every opportunity to drink Excessive intake of sports drink may cause gut upset
Units of energy
1 cal = 4.18 kJ 1000kj = 1 MJ
Obesity
1) BMI ≥ 30 2) Other measures for assessing overweight /disease risk (based on central body fat): •Waist circumference 'Increased risk' of chronic disease >94cm M, >80cm F 'Greatly increased risk' >102cm M, >88cm F http://www.health.gov.au/internet/abhi/publishing.nsf/Content/How%20do%20I%20measure%20myself-lp •Waist to hip ratio (WHR) 'Increased risk' of chronic disease >0.9 M, >0.8 F
Enhancing glycogen resynthesis
1. Depleted stores: the lower the exercise-induced concentration of glycogen, the faster the rate of subsequent resynthesis 2. Immediate intake of CHO after exercise 3. Amount of CHO consumed post-exercise: 1.0-1.5 g CHO/kg BM in the first 30-60 min, 7-10 g CHO/kg BM within the next 24 h 4. Focus on foods with a high glycemic index
g/kg pre, during and post exercise- Carbohydrates
1. Pre-event meal 1-4g/kg BW eaten 3-4hrs pre event 2.Pre-event snack 1-2g/kg BW eaten 1-2hrs pre event 3. During prolonged mod-high intensity exercise 1g/min (esp. heat + sub-optimal pre-exercise fuel stores) 4. Post event 1g/kg BW within 30mins (rapid recovery post exercise, or multi-events esp. when there's < 8hrs until next session). May enhance performance in prolonged aerobic exercise Maintains blood glucose Provides energy to muscles Reduces ratings of perceived exertion About every 15-20 minutes Approximately 1 gram per minute, or about 60 grams an hour
Recommended nutrients
12-25% from protein 45-65% from carbohydrate 15-30% from fats with no more than 10% of this coming from saturated fats
Protein/AA stores
120 grams free in skeletal muscle
Where is carbohydrate stored & how much?
15. An average size adult can store how many grams of glycogen in large muscles of the body? C) 400 . 1 gram of glycogen also stores how many grams of water? B) 3 The body stores carbohydrate as glycogen in the muscles and liver, however its storage capacity is limited.
Hydration assessment,
1L of water lost from skin will remove 2.4MJ of heat from the body Acute changes in body mass Haematological indices oElectrolytes e.g. Na oFluid reg. hormones Urinary indices oColour oSpecific Gravity oOsmolarity oVolume Preferred measurement tools should be: •Non-invasive •Economical •Technically simple to operate •Portable and robust •Valid •Precise •Not influenced by factors unrelated to hydration status Weigh athlete in minimal clothing prior to event/training •Weight athlete in minimal clothing and towel dried post even/training •Calculate body weight loss •1kg = 1L fluid lost •Replace 150% of weight lost Example •Pre game = 80kg •Post game = 78kg •2kg weight loss = 3L fluid to be replaced
Peptide bonds
2 joined amino acids = dipeptide 3 joined amino acids = tripeptide <100 amino acids = polypeptide >100 amino acids = protein Simple AA's (whey) digested faster than complex AA's (casein)
Monosaccharides
3 Principal Monosaccharides: Glucose Fructose Galactose Building blocks of naturally occuring di-, oligo- and poly- saccharides Free glucose and fructose occur in cooked/dried fruit and small amounts in raw fruit, berries and veggies
Servings of food
5-6 serves of vegetables (including lots of greens) 2 serves of fruit 2-4 serves of dairy 2-3 serves of meat
Estimated Average Requirement (EAR)
A daily nutrient level estimated to meet the requirements of half the healthy individuals in a particular life stage and gender group
Villi
A villus is a fingerlike projection on the inner surface of the small intestine Each has microscopic appendages called microvilli that are exposed to the intestinal lumen Microvilli are also known as the brush border for the intestinal epithelium because of their shape The structure of a villus greatly increases the rate of nutrient absorption by providing more surface area
Accessory organs
Acid chyme mixes with the digestive juices from the liver, gallbladder, & pancreas Liver Produces bile-emulsification of fats. Bile also contains pigments that are by-products of red blood cell destruction, which are eliminated from the body with the feaces Gallbladder Stores bile until it is needed Pancreas Produces several hydrolytic enzymes (pancreatic lipase) and an alkaline solution that acts as a buffer, offsetting the acidity of chyme. The pancreatic enzymes include protein-digesting enzymes (proteases) that are secreted into the duodenum in inactive form
Role of AEP
An Accredited Exercise Physiologist (AEP) describes a university-trained and AAESS accredited exercise specialist who possesses the knowledge, skills and competency to design and deliver general physical activity advice and clinical exercise prescription for apparently healthy persons and for those persons with chronic and complex diseases. The aim of the intervention is to facilitate long-term behaviour change by encouraging the self-management of health through exercise and other lifestyle modifications, with a view to preventing and treating disease.
Role of the APD
An Accredited Practising Dietitian (APD) describes a university-trained and DAA accredited dietitian and nutritionist who possesses the knowledge, skills and competency to provide expert nutrition and dietary advice. APDs design and deliver Medical Nutrition Therapy (MNT) which forms an integral part of the management of people with chronic and complex diseases. The aim of the intervention is to facilitate long term behaviour change by encouraging the self-management of health through nutrition, diet and other lifestyle modifications, with a view to preventing and treating disease.
Lipids
Animal and plant sources Fats- solid lipids at room temperature Oils- fluid lipids at room temperature Fat soluble vitamins Triacylglycerols/Triglycerides = 95% of dietary lipids, made up of fatty acids: Saturated- carbon-carbon bonds fully saturated with hydrogen atoms Mono-unsaturated- single double-bond formed due to 2 hydrogen atoms missing Poly-unsaturated- two or more double-bond formed due to missing hydrogen atoms Phospholipids Sterols
Types of eating disorders
Anorexia Nervosa Bulimia Nervosa Binge Eating Disorder Eating Disorder Not Otherwise Specified (EDNOS) Muscle Dysmorphia
Anthropometric data
Anthropometrics are the objective measurements of body muscle and fat . They are used to compare individuals, to compare growth in the young, and to assess weight loss or gain in the mature individual. Weight and height are the most frequently used anthropometric measurements, and skinfold measurements of several areas of the body are also taken.
Sweat composition analysis
Athlete wears 2-4 sweat patches during a hard training session. Patches are removed and placed in test tubes which are then spun down to analyse the electrolyte content of the sweat Determines how much sodium (or salt) the athlete loses in sweat. Example During training an ultra endurance athlete's sweat contained 1.5g/hr of sodium (multiply by 2.5 to get amount of salt = 3.75g salt). 1g sodium = 2.5g table salt = 2.2L Gatorade = 1 salt tablet =70g pretzels Some losses may be high enough to warrant replacement
Requirements of different athletes
Average person 0.75-0.85 Recreational athlete 0.9 -1.2 Strength training (initially) 1.5 - 1.7 Strength training (steady) 1.0 - 1.2 Endurance training 1.2 - 1.4 Elite endurance 1.6 Power sports 1.4-1.7 Adolescent/growing sports. 2.0 Pregnant athletes +10g/day (2nd & 3rd tri) Breastfeeding athletes + 20g/day
Deficiency/Toxicity risks
B-complex vitamins and vitamin C are water-soluble vitamins that are not stored in the body and must be replaced each day. These vitamins are easily destroyed or washed out during food storage and preparation. The B-complex group is found in a variety of foods: cereal grains, meat, poultry, eggs, fish, milk, legumes and fresh vegetables. Citrus fruits are good sources of vitamin C. Use of megadoses of vitamins is not recommended. Vitamins are essential nutrients found in foods. The requirements are small but they perform specific and vital functions essential for maintaining health. The two types of vitamins are classified by the materials in which they will dissolve. Fat-soluble vitamins -- vitamins A, D, E and K -- dissolve in fat before they are absorbed in the blood stream to carry out their functions. Excesses of these vitamins are stored in the liver. Because they are stored, they are not needed every day in the diet. By contrast, water-soluble vitamins dissolve in water and are not stored; they are eliminated in urine. We need a continuous supply of them in our diets. The water-soluble vitamins are the B-complex group and vitamin C. Water-soluble vitamins are easily destroyed or washed out during food storage or preparation. Proper storage and preparation of food can minimize vitamin loss. To reduce vitamin loss, refrigerate fresh produce, keep milk and grains away from strong light, and use the cooking water from vegetables to prepare soups. (See Table 1.) Vitamin B-Complex Eight of the water-soluble vitamins are known as the B-complex group: thiamin (vitamin B1), riboflavin (vitamin B2), niacin, vitamin B6, folate, vitamin B12, biotin and pantothenic acid. These vitamins are widely distributed in foods. (See Table 2.) Their influence is felt in many parts of the body. They function as coenzymes that help the body obtain energy from food. They also are important for normal appetite, good vision, healthy skin, healthy nervous system and red blood cell formation. Beriberi, pellagra and pernicious anemia are three well-known B-vitamin deficiencies. These diseases are not a problem in the United States, but occasionally they occur when people omit certain foods or overeat certain foods at the expense of others. Alcoholics are especially prone to thiamin deficiency because alcohol replaces food.Vegans will need a B12 supplement. When grains and grain products are refined, essential nutrients lost during processing are put back into these foods through a process called enrichment. Among the nutrients added during the enrichment process are thiamin, niacin, riboflavin, folate and iron. Some examples of enriched grain products are white rice, many breakfast cereals, white flour, breads, and pasta. For some populations, rice is the main dietary staple. When "polishing" rice (removing its outer layers) became popular, thiamin deficiency, or beriberi, increased significantly.
BMI Classifications
BMI = body mass index = wt(kg)/ht(m)2 Underweight <18.50 <18.50 Severe thinness <16.00 <16.00 Moderate thinness 16.00 - 16.99 16.00 - 16.99 Mild thinness 17.00 - 18.49 17.00 - 18.49 Normal range 18.50 - 24.99 18.50 - 22.99 23.00 - 24.99 Overweight ≥25.00 ≥25.00 Pre-obese 25.00 - 29.99 25.00 - 27.49 27.50 - 29.99 Obese ≥30.00 ≥30.00 Obese class I 30.00 - 34.99 30.00 - 32.49 32.50 - 34.99 Obese class II 35.00 - 39.99 35.00 - 37.49 37.50 - 39.99 Obese class III ≥40.00 ≥40.00
Bicarbonate
Bicarbonate is the body's most important extracellular buffer Mechanism: body's bicarbonate reserves Delays fall in intracelllar bicarbonate ( muscle's extracellular buffering capacity) which ability to dispose of excess hydrogen ions & lactate produced through anaerobic glycolysis Purported Benefit: Enhanced anaerobic performance (1-10 min. events) Side Effects: Abdominal cramps, diarrhoea, GI discomfort - 1 hr after ingestion. 2 methods used for consumption Acute loading - 0.3 g sodium bicarbonate/kg BM 60-180 min before training or competition. Chronic loading - 0.5 g sodium bicarbonate/kg BM, split into four doses spread over the day, consumed for 5-6 consecutive days. It is important that at least 1 litre of water is consumed with the acute loading protocol, and sufficient water is consumed with the chronic loading protocol.
Protein synthesis and degradation
Body constituents are in a dynamic state- proteins are constantly being synthesised and degraded In healthy adults about 4g protein /kg BW are synthesised each day In newborn infants 12 g protein/kg BW/d decreasing to 6g/kg by 1 yo Carefully matched to size, shape, body composition Energy required for both protein synthesis and degradation 4kJ/g
Micro nutrients mineral
Calcium Chromium Copper Fluoride Iodine Iron Magnesium Manganese Molybdenum Phosphorus Potassium Selenium Sodium Zinc
Macro nutrient kJ
Carbohydrate (17), protein (17), fat (37), alcohol (29)
When does fuel during an event become important?
Carbohydrate stored as glycogen is an easily accessible source of energy for exercise. How long this energy supply lasts depends on the length and intensity of exercise and can range anywhere from 30 to 90 minutes or more. To avoid running out of energy during exercise, start with full glycogen stores, replenish them during exercise and refill them after exercise to be ready for the next workout. Glycogen is the source of energy most often used for exercise. It is needed for any short, intense bouts of exercise from sprinting to weight lifting because it is immediately accessible. Glycogen also supplies energy during the first few minutes of any sport. During long, slow duration exercise, fat can help fuel activity, but glycogen is still needed to help breakdown the fat into something the muscles can use. Adequate carbohydrate intake also helps prevent protein from being used as energy. If the body doesn't have enough carbohydrate, protein is broken down to make glucose for energy. Because the primary role of protein is as the building blocks for muscles, bone, skin, hair, and other tissues, relying on protein for energy (by failing to take in adequate carbohydrate) can limit your ability to build and maintain tissues. Additionally, this stresses the kidneys because they have to work harder to eliminate the byproducts of this protein breakdown. One gram of carbohydrate provides four calories of energy. Athletes often talk about carbohydrate loading and carbohydrate depletion which refers to the amount of carbohydrate energy we can store in our muscles. This is generally around 2,000 carbohydrate calories, but we can change this number through depletion and loading. During depletion (from diet, exercise or a combination) we use up the stored carbohydrate. If we don't replenish these stores, we can run out of fuel for immediate exercise. Athletes often refer to this as "bonking" or "hitting the wall." In the same way, eating large amounts of carbohydrates can increase these stores. This is often referred to as carbohydrate loading or carbo-loading. While every person is unique, and our carbohydrate storage capacity will vary, according to Dan Benardot, the author of Advanced Sports Nutrition, "Humans can store approximately 350 grams (1,400 kilocalories) in the form of muscle glycogen, an additional 90 grams (360 kilocalories) in the liver, and a small amount of circulating glucose in the blood (~5 grams, or about 20 kilocalories). The larger the muscle mass, the greater the potential glycogen storage but also the greater the potential need." Another common figure in the research indicates that maximal glycogen storage is approximately 15 grams per kilogram of body weight (15 grams per 2.2 pounds). With this math, a 175-pound athlete could store up to 1200 grams of glycogen (4,800 calories) which could fuel high intensity exercise for quite some time. How Carbohydrate Fuels Exercise Carbohydrate stored as glycogen is an easily accessible source of energy for exercise. How long this energy supply lasts depends on the length and intensity of exercise and can range anywhere from 30 to 90 minutes or more. To avoid running out of energy during exercise, start with full glycogen stores, replenish them during exercise and refill them after exercise to be ready for the next workout. Carbohydrate has other specific functions in the body including fueling the central nervous system (CNS) and brain.
Enzymes involved in digestion
Carbohydrates - amylase Protein - protease Fat - lipase Peptidases- Digest protein Trypsin- Digest protein Dipeptidases- Digest protein into single amino acids Nucleases- Digest foreign DNA Lipases- Finish lipid digestion by breaking fatty acid chains from glycerol Amylases- Digest carbohydrates Disaccharidases- Digest carbohydrates
Carnitine
Carnitine non-essential nutrient facilitates transfer of fatty acids across mitochondria membranes supplementation does not increase muscle carnitine or enhance exercise performance.
Digestion & absorption - Small intestine
Chyme moves past the pyloric sphincter into the small intestine Main site of nutrient digestion and absorption Approx 5 m long (NR 3-7m) 3 sections: Duodenum - approx 30 cm long Jejunum- approx 2.5 m long Ileum- 2-4 m long Surface area approx 300m²- folds of Kerckring, villi, microvilli Digestive enzymes found in brush border Cell turnover every 3-5 days
Common signs and symptoms - how to recognize
Cold intolerance Weakness and fainting Hair loss, lanugo hair Abdominal pain, constipation, bloating Coarse, yellow skin Delayed growth, delayed puberty Weight fluctuations (loss, cycling) •Behaviour changes •Refusal/difficulty maintaining a healthy weight •Intense fear of becoming overweight •Thinking/talking about food beyond usual •Expresses "feeling fat" even when normal weight •Belief that the body must be perfect/improved •Becoming moody, irritable or depressed •Social isolation, particularly @ meals Bathroom visits after meals Frequent weighing (more than once/week) Exercising beyond normal/required for training Feeling cold, wearing bulky clothes Appearing "happy" when clearly not
Symptoms of dehydration
Dehydration results in an increase in heart rate, body temperature and perception of effort leading to reduced physical and mental performance.
Lipid digestion
Digestion Trigs must be hydrolised to FA and monoglycerols before absorption Process starts in stomach- churning + bile → emulsification into small bile-acid coated droplets with large surface area for digestive enzymes to act Absorption Efficient >95% dietary lipid absorbed (trigs, phospholipids, FSVit) Cholesterol and other sterols <30% absorbed
How to manage nerves and decreased appetite
Eating healthy foods at the right times in the right portions is the simplest key to ensuring that your diet isn't too affected by your anxiety. You need to ignore instincts and go on logic. If you're overeating, try to avoid buying anything that could be used as a temptation for stress eating. You can't eat ice cream if you don't have it in the house. If you're under-eating, set up reminders for yourself. Have an alarm go off at breakfast, lunch, and dinner, and then force yourself to eat a good helping of healthy meals. You'll also need to commit to taking steps towards combatting your overall anxiety. I've helped thousands of those with an altered appetite control their anxiety forever. You need to start with my anxiety test, which looks at what anxiety you're experiencing and how it affects you. Drinking smoothies
Energy balance equation
Energy balance equation •Energy intake greater than energy expenditure Is it that simple? •Body aims for homeostasis/equilibrium •Central regulation aims to prevent weight loss/gain •Physiological adjustments can ↓ metabolic rate •Set point = genetic weight expectation - can be shifted UP, but rarely down
Energy balance
Energy balance is dynamic Regulation achieved by hypothalamus Receives neural & endocrine signals from body Integrates these through complex network of neural pathways Follows by sending neural signals to regulate appetite and energy expenditure Short term signals indicating energy sufficiency: Blood glucose, amino acid, fatty acid levels Stomach & gut derived hormones Signals from liver Long-term signals: Hormones secreted by adipose tissue: to fat stored there- leptin Leptin- directly proportional to fat stores- body's fuel gauge During weight loss/starvation BMR can drop by ~20%
Physical activity
Energy expenditure from movement/physical work- both conscious movements and subconscious (eg.fidgeting) Variable Bed rest 1.3 x BMR Sedentary job and TV during leisure time 1.55 x BMR Peak Farming season- Farmers 2.0 x BMR Endurance athlete eg. Tour de France 3.0 x BMR Kids- active 1.8 x BMR
Female athlete triad
Energy imbalance (greater out than in) Low energy availability Lower oestrogen levels Less calcium blood-bone (lower density) Desire to improve performance Messages from coaches & team mates Competitive thinness Beliefs around low body fat levels directly relating to performance Pressures associated with being an "athlete" Media attention Sports clothes eg. netball, basketball, swimming
Thermic effect of food
Energy required to absorb, digest, transport, interconvert and store foods consumed <10% of total intake Depends on size and composition of meal consumed Protein exhibits higher DIT vs carbs and fat
BMR
Energy required to sustain basic processes of life: Breathing Circulation Tissue repair/renewal In most people accounts for 70% of all energy used (excl. very active) Factors affecting BMR: Body size & composition (esp. Muscle mass) Gender Age
Dietary guidelines for australians
Enjoy a wide variety of nutritious foods Eat plenty of vegetables, legumes and fruits Eat plenty of cereals (including breads, rice, pasta and noodles), preferably wholegrain Include lean meat, fish, poultry and/or alternatives Include milks, yoghurts, cheeses and/or alternatives Reduced-fat varieties should be chosen, where possible Drink plenty of water and take care to: Limit saturated fat and moderate total fat intake Choose foods low in salt Limit your alcohol intake if you choose to drink Consume only moderate amounts of sugars and foods containing added sugars
Acclimitisation How it helps How long it takes
Exercise in the heat increases heart rate, skin and core temperature and sweat rate. Acclimatisation is needed to regulate these. Heart rate reduction and body temp regulation can occur after 4-5 days to heat exposure Loss of sodium in sweat is minimised by the body's ability to reabsorb sweat sodium. The sodium conserving effect depends on the adrenal cortex and the hormone aldosterone which increase in the blood during acclimatisation.
Fluid replacement During? Post?
Fluid Guidelines: 300-600ml with pre-event meal 150-300ml every 15-20 mins up to 45 mins before the event Take pre and post body weight to work out fluid losses Loss of 1 kg = Loss of 1L fluid → Ingest 1.5L of fluid per kg weight loss (aim to replace 150% of fluid loss over next 2-4hrs)
Digestion in oesophagus
From the mouth the bolus passes through the pharynx into the oesophagus 25-30 cm long Regulated by "swallowing centre" in the medulla Oesophageal sphincter relaxes to enable swallowing, simultaneously larynx moves upwards inducing the epiglottis to shift over the glottis This stops food going down the airway into the lungs Peristalsis- progressive wave-like motion moves the food down through the oesophagus to the stomach- time <10 seconds Reaches the gastro-oesophageal sphincter
Questions an AEP can ask
General Diet History • Dietary habits • Regular eating patterns • Core food groups • Have they seen an APD? Detailed Exercise History • Previous AEP input? • Previous exercise experience • Contraindications or barriers to exercise • Particular consideration to cardiovascular, metabolic, neurological or musculoskeletal conditions that may affect exercise capacity/maintenance • Pre-exercise screening & risk factor stratification • Measurement of physiological parameters
Questions APD can ask
General Exercise History • Current or previous leisure time activity • Occupational, household, incidental activity • Have they seen an AEP? Detailed Diet History • Previous APD input? • Previous dietary modifications/hx • Detailed eating pattern • Food types/brands • Detailed serving sizes • Food frequency • Cooking methods/skills • Limitations/practical issues • GIT conditions
Recommended Carbohydrates
Glucose is an essential energy source for the brain, red blood cells and renal medulla- daily requirement about 180g/d Body can make up to 130g/d from non-CHO sources So minimum amount dietary CHO required per day to avoid ketosis = 50-180g/d (pregnancy 100-230g/d) kJ Value of Carbohydrates 17kJ/g
Carbohydrate breakdown
Glycolysis- breakdown of glucose Gluconeogenesis- conversion of non-carbohydrates to glucose Glycogenolysis- conversion of stored glycogen to glucose Glycogenesis- synthesis of glycogen from glucose
Goals of training diet
Goals: 1. provide energy for training demands 2. provide nutrients for training & health 3.promote recovery
Group A AIS supplements
Group A Supplements are supported for use in specific situations in sport These sports foods and supplements: provide a useful and timely source of energy and nutrients in the athlete's diet, or have been shown in scientific trials to benefit performance, when used according to a specific protocol in a specific situation in sport. Examples Sports drink, Sports gel, Sports confectionery, Liquid meal, Whey protein, Sports bar, Electrolyte replacement
Group B
Group B supplements are deserving of further research and considered for provision to athletes only under a research protocol. These sports foods and supplements: have received some scientific attention, sometimes in populations other than athletes, or have preliminary data which suggest possible benefits to performance and are of particular interest to athletes and coaches. Anti-oxidants C and E Carnitine HMB Fish oils Quercetin Probiotics for immune support Other polyphenols as antioxidants and anti-inflammatories
Grroup C
Group C supplements have little proof of beneficial effects This category includes the majority of supplements and sports products promoted to athletes. These supplements, despite enjoying a cyclical pattern of popularity and widespread use, have not been proven to provide a worthwhile enhancement of sports performance. Current scientific evidence shows that either the likelihood of benefits is very small or that any benefits that occur are too small to be useful. In fact, in some cases, these supplements have been shown to impair sports performance, with a clear mechanism to explain these results. 17/09/2014 11 AIS Sports Supplement program Sports drink Sports gel Sports confectionary Liquid meal Whey protein Sports bar Calcium supplement Iron supplement Probiotics for gut protection Multivitamin/mineral Vitamin D Electrolyte replacement Caffeine Creatine Bicarbonate B-alanine Beetroot Juice Group A Supplements are supported for use in specific situations in sport These sports foods and supplements: provide a useful and timely source of energy and nutrients in the athlete's diet, or have been shown in scientific trials to benefit performance, when used according to a specific protocol in a specific situation in sport. http://www.ausport.gov.au/ais/nutrition AIS Sports Supplement program Anti-oxidants C and E Carnitine HMB Fish oils Quercetin Probiotics for immune support Other polyphenols as antioxidants and anti-inflammatories Group B supplements are deserving of further research and considered for provision to athletes only under a research protocol. These sports foods and supplements: have received some scientific attention, sometimes in populations other than athletes, or have preliminary data which suggest possible benefits to performance and are of particular interest to athletes and coaches Ribose Lactaway Coenzyme Q10 Vitamin supplements when used in situations other than summarised in Group A Ginseng Other herbals (cordyceps, rhodiola rosea) Glucosamine Chromium picollinate Oxygenated waters MCT oils ZMA Inosine Pyruvate
Pre event hydration
Hydration needs to be tailored to the individual athlete Deliberate hydration strategies leading into competition is warranted however need to be aware of hyponatraemia Fluid overloading may be beneficial however it can lead to: •Excessive urination •Gut discomfort •Increased body weight Start event hydrated Ensure fluid losses are recovered after each session Consume 300-600ml with pre event meal 300-400ml in the 15-20minutes before event
Hyponatraemia
Hyponatremia or hyponatraemia is defined as a low sodium concentration in the blood.Too little sodium in the diet alone is very rarely the cause of hyponatremia, although it can promote hyponatremia indirectly and has been associated with Ecstasy-induced hyponatremia.[2] Sodium loss can lead to a state of low blood volume, which serves as a signal for the release of anti-diuretic hormone (ADH).ADH release leads to water retention and dilution of the blood resulting in a low sodium concentration. Exercise-associated hyponatremia (EAH) is common in marathon runners and participants of other endurance events.[3] 13% of the athletes who finished the 2002 Boston Marathon were in a hyponatremic state, i.e. their salt levels in their blood had fallen below an acceptable level.[citation needed]
Protein timing
Include protein in most meals/snacks throughout day Include 10-20g protein in post training snack (ideally within 30-45mins)
Glycemic response
Influenced by: Level of processing Other components of food eg fat/protein Total Glycaemic Response also influenced by amount/quantity Glycaemic load= Amount available CHO x GI/100
Digestion & absorption - Stomach
J Shaped organ, left side of the abdomen, under the diaphragm Extends from gastro-oesophageal sphincter to duodenum Contains 4 main regions 1.Cardia 2.Fundus 3.Body/Corpus 4.Antrum The volume of the stomach when empty is around 50ml When full it can accommodate 1-1.5L The digestive process is facilitated by gastric juices- produced by millions of gastric glands in stomach lining Hydrochloric Acid pH 2 Converting/activating zymogen pepsinogen to form pepsin Denaturing proteins Releasing various nutrients from organic complexes Acting as a bactericide agent, killing many bacteria ingested with food Three key enzymes found in gastric juice: Pepsin- protease- hydrolyses protein α-amylase (originates from salivary glands in mouth)- hydrolyzes starch until inactivated by pH of gastric juice Gastric lipase- hydrolises primarily short and medium chain triacylglycerols- 20% of lipid digestion in humans Additional factor- Intrinsic factor- needed to absorb Vit B12 Gastric secretions are regulated by multiple mechanisms Hormones Peptides Bolus of food mixed with gastric juice = chyme Gastric emptying usually takes 2-6 hours post meal
Macro vs micro nutrients - the difference
Major or macrominerals >100mg/day needed Trace or microminerals < 100mg/day needed
How do endogenous & exogenous CHO's affect recovery from exercise
Many studies have shown that carbohydrates (CHO) effectively restore glycogen post-exercise [1]. Some have also suggested that the addition of PRO to a CHO drink may produce further improvements . CHO and PRO ingestion during recovery may result in higher CHO oxidation during subsequent exercise, which may be more beneficial to endurance performance because of preservation of endogenous substrates
Urine specific gravity
Measures the density of urine compared to water Non-invasive, inexpensive and highly portable Easy to use with immediate feedback Relatively easily interpreted by athletes Not gold standard Not valid for at least 2 hours post events when athletes are consuming high volumes Most effective when: first urine sample of the morning, mid stream Status USG of waking sample Slightly hyperhydrated 1.017 - 1.021 Well hydrated 1.022 - 1.023 Euhydrated 1.024 - 1.026 Slightly dehydrated 1.027 - 1.028 Very Dehydrated 1.029 - 1.031
Athletes at greater risk
Most likely to see either EDNOS, then BN, then AN Most common sports (but not exclusively): Those that emphasise size/shape/weight as key performance aspect Weight category (can promote unhealthy weight cycling)
Digestion & absorption - The mouth
Mouth Pharynx (Throat) Entryway to the digestive tract Food is chewed by action of teeth and jaw muscles Mixes with saliva (produced by salivary glands)- about 1L/d Saliva helps dissolve foods and is composed of: Water (99.5%) Electrolytes- sodium, potassium, chloride Enzymes (alpha-amylase- hydrolyses starch) Mucus- lubricates food and protects oral mucosa Trace amounts of IgA, urea, phosphates, bicarbonate Lingual gland on tongue & back of mouth- produces lingual lipase which hydrolyses triglycerides in the stomach Chewed food mixed with saliva= Bolus
AGHE- NRV
Nutrient Reference Values (NRVs) for Australia and New Zealand provide recommended intakes for energy (kilojoules), protein, carbohydrate, fibre, fats, vitamins, minerals and other nutrients based on age, sex and life stages The NRVs were released by the National Health and Medical Research Council (NHMRC) to replace the Recommended Dietary Intakes (RDIs). They recommend changes not only to the amount of nutrients we need but also make reference to some new nutrients The new recommendations cover a wider range of nutrients. They include a set of values for each nutrient instead of a single value and there are recommendations about intakes of certain nutrients that may reduce the risk of chronic diseases
Intestinal bacteria
Over 400 species of at least 40 genera isolated from human faeces to date Bacterial count as high as 1012 per gram of GI tract Bacteria found throughout GI tract- not just large intestine Bacteria use predominantly carbohydrates as substrates for growth- fermentation
Factors which impact on fluid loss
Performance is significantly impaired with a body fluid deficit of as little as 2%. This is only a 1.4kg loss for a 70kg athlete. Dehydration can cause general fatigue and reduces mental function, affecting your decision making, concentration, motor skills and muscle endurance.\ As a general rule, consume 35-40ml per kg of body weight, plus fluid losses. Eg. A 70kg person should consume approximately 2450-2800ml PLUS fluid losses from exercise.
Glycemic Index
Plasma glucose levels: Rise 5-45 minutes after any meal that contains sugar or digestible starch = Glycaemic response Return to fasting levels 2-3 hrs later Glycaemic Index- " Incremental area under the blood glucose response curve following a 50g carbohydrate portion of a test food, expressed as a % of the response to the same amount of carbohydrate from a standard food eg. Glucose/white bread taken by the same subject"
Polyls
Polyols are neither sugars nor alcohols eg. Sorbitol Found naturally in some fruits Used commercially as a sucrose replacement to make "sugar free" products They are carbohydrates with a chemical structure that partially resembles sugar and partially resembles alcohol, but they don't contain ethanol as alcoholic beverages do They are incompletely absorbed and metabolized by the body, and consequently contribute fewer calories
Disaccharides
Principal disaccharides: Sucrose- found widely, in fruit, berries, vegetables, sugar cane, beets Lactose- main sugar in milk/dairy products Maltose- sprouted wheat, barley
RDI for protein
RDI protein 0.75g/kg for adult women 0.84g/kg for adult men Around 1g/kg for pregnant and breast-feeding women, and for men and women over 70 years. So, for example, a 75kg adult male would need 63g of protein per day. Other, more specific for growing children eg. 2g/kg
Effects of protein on MPS & MPB
REX in the fasted state increased protein synthesis but also protein breakdown (degradation) In the absence of available nutrients, protein breakdown likely provides AA's for synthesis of new functional protein assembly Without nutrition provision, exercise may promote only modest (if any) increase in muscle (myofibrillar or mitochondrial) protein synthesis Nutrient-training interactions need to be considered to enhance muscle mass & the specificity of adaption to exercise. In younger subjects - 10g of EAA resulted in maximal stimulation of myofibrillar protein synthesis In older subjects - maximal MPS was also achieved at a dose of 10g of EAA, but the response was slower MPS displayed a dose response to dietary protein was maximally stimulated at 20g. No further increase >20g. Conclusion: Studies suggest 10-20g high-quality protein is sufficient to maximally stimulate muscle protein synthesis following REX.
What should the training diet include?
Recommendations: Variety High CHO Low fat Adequate protein Adequate dietary fibre Adequate fluids Adequate vitamins & minerals
Fluid replacement post
Rehydration should be considered an immediate priority ~150% of the post fluid deficit needs to be replaced over 2-4 hours post exercise. The addition 50% is required to cover urine losses and ongoing sweating For losses >2L sodium replacement will assist in fluid retention. You may be able to get this from a post event meal. Caffeine containing drinks and alcohol should be avoided Post exercise activities such as spas and saunas should be avoided as they will exacerbate fluid loss
Characteristics of eating disorders
Serious, potentially life-threatening psychiatric illness Develop over time (but can be fast or slow) Over-evaluation of body shape Dietary restriction (may start by following a 'healthy diet' ) Nutritional messages taken to extremes Control of body shape, size and maturation A way of coping, becomes an obsession Anxiety & depression are commonly seen
Oligosaccharides
Short-chain carbohydrates Degree of polymerisation 2-10 Maltodextrins Other oligosaccharides: Raffinose,verbacose eg. in lentils/beans Non-digestible oligosaccharides: Not susceptible to brush-border enzyme breakdown Fructans-Inulin, fructo-oligosaccharides eg. in artichokes Become known as prebiotics
Essential Amino acids
Six amino acids are considered conditionally essential in the human diet, meaning their synthesis can be limited under special pathophysiological conditions, such as prematurity in the infant or individuals in severe catabolic distress. These six are arginine, cysteine, glycine, glutamine, proline and tyrosine.
Formulation of sports drinks
Sports drinks are designed to deliver a balanced amount of carbohydrate and fluid to allow an athlete to simultaneously rehydrate and refuel during exercise. According to various expert position stands, the compositional range which provides rapid delivery of fluid and fuel and maximises gastric tolerance and palatability is 4-8% (4-8 g/100 ml) carbohydrate and 23-69 mg/100 mL (10-30 mmol/L) sodium The type and quantity of carbohydrates provided in sports drinks varies according to the manufacturer, with factors such as taste, osmolarity (concentration of individual particles) and gut tolerance being considered. Some newer drinks contain "multiple transportable carbohydrates" - a blend of carbohydrates such as glucose and fructose which are absorbed from the intestine via different transporter molecules. The purpose of such mixtures is to bypass the usual limitation on gut uptake of glucose-based sugars which occurs at rates of ~ 60 g/h. Studies have shown that when carbohydrates are consumed at high rates (> 60 g/h) during exercise to meet new guidelines for prolonged strenuous events, these drinks are more effective than glucose-based products in maintaining gut comfort, promoting muscle carbohydrate oxidation and enhancing performance The electrolyte content of sports drinks, particularly sodium, helps to preserve the thirst drive. Sodium concentrations of ~ 10-25 mmol/L enhance the palatability and voluntary consumption of fluids consumed during exercise. Sodium concentrations higher than those typically provided in commercial sports drinks are needed to restore fluid balance and reduce urine losses during the reversal of moderate-severe dehydration. They may also be needed to replace sweat sodium losses during exercise in situations of high losses (e.g. salty sweaters, prolonged exercise). > Other electrolytes (e.g. magnesium, potassium and calcium) may be included in sports drinks. Current evidence indicates that significant quantities of magnesium are not lost during exercise so it is unlikely that additional magnesium will enhance hydration goals or reduce cramping. Protein or amino acids (2% or 2 g/100 ml) can be found in a small number of commercially available sports drinks. Some studies show that sports drinks providing protein/amino acids are superior to carbohydrate-electrolyte drinks in enhancing performance or recovery in specific exercise situations (e.g. prolonged exercise). The case for consuming protein during recovery after exercise is strong and can be achieved by a range of sports products and everyday foods other than sports drinks. The benefits of consuming protein during exercise on performance of exercise are contentious. A meta-analysis of the literature (11 studies) suggested a methodological bias exists with the results of studies; benefits are seen with time to exhaustion protocols and when protein provides additional energy to sub-optimal intakes of carbohydrate. It was concluded that any ergogenic benefits may result from a generic effect of additional energy intake rather than a unique benefit of protein . Further research is warranted but should also consider the effects of amino acids/ protein on the flavour profile of a drink. The taste and temperature of sports drinks are also important factors in meeting hydration goals. Studies show that athletes more closely match fluid intake to sweat losses when offered flavoured sports drinks compared to water (Minehan et al. 2002, Maughan et al. 1993). Cool fluids are generally more palatable for athletes who are exercising in hot conditions or have become hot though the heat gain associated with high-intensity exercise.
Polysaccharides
Starch polysaccharides (α-glucans) Non-starch polysaccharides (non-α-glucans) Starch- storage carbohydrate of plants Granules comprised of 2 polymers- amylose and amylopectin Starch not digested in the small intestine = resistant starch Non-starch polysaccharides- mostly from plant cell walls Cellulose Hemicellulose Pectins Gums & Mucilages Algal polysaccharides eg. Gennan, agar Fermented in the large intestine
Caffeine
Stimulant, or "wake-up," effect Caffeine is readily absorbed by the body and carried around in the bloodstream, where its level peaks about one hour after consumption. Stimulates the nervous and cardiovascular systems. Can also affect the brain resulting in elevated mood, increased attentiveness, so a person can think more clearly and work harder, increases the heart rate, blood flow, respiratory rate, and metabolic rate for several hours. Effects are dependant on: - Amount of caffeine ingested - Male vs female - Persons height, weight, and age - Absorption rate Dose Studies show doses of 1-3mg/kg are effective and a plateau seems to occur at 3mg/kg. For example, 150mg for an 80kg athlete Supplement protocol Depends on the sport Before the exercise bout Spread throughout exercise When fatigue starts to occur. Low: 85-250mg/day (1-3.5mg/kg BM) Moderate: 300-400mg/day (4-6mg/kg BM) Children <12 recommended to have no more than 2.5mg/kg BM Pregnancy <300mg/day ??
Ergogenic aids
Substances promoted as ergogenic aids Arginine is a nonessential amino acid. Boron is a nonessential mineral. Brewer's yeast is falsely promoted as an energy booster. Cell salts are sold as health promoting. Coenzyme Q10 is not effective in improving athlete performance. DNA (deoxyribonucleic acid) is falsely promoted as an energy booster. Epoetin is illegally used to increase oxygen capacity. Gelatin is not a strength enhancer. Ginseng has many side effects. Glycine is a nonessential amino acid. Growth hormone releasers do not enhance performance. High doses of guarana can stress the heart and cause panic attacks. Herbal steroids or plant sterols do not enhance hormone activity. Inosine has been shown to reduce endurance of runners. Ma huang has many dangerous side effects. Niacin does not enhance performance and has side effects. Octacosanol has false promotions. Ornithine - a nonessential amino acid. Oryzanol - a plant sterol. Pangamic acid does not speed oxygen delivery. Phosphate pills do not extend endurance or increase efficiency of aerobic metabolism. Pyruvate has common side effects of gas and diarrhea. Ribose has some false claims. RNA (ribonucleic acid) does not enhance performance. Royal jelly is falsely promoted. Sodium bicarbonate may cause intestinal bloating and diarrhea. Spirulina is potentially toxic. Succinate is not a metabolic enhancer. Superoxide dismutase (SOD) is useless; it is digested. Wheat germ oil is not an energy aid.
Electrolytes
Sweat loss from prolonged exercise leads to a loss of electrolytes and water from the body Sodium is the principle electrolyte lost in sweat during prolonged bouts of sweating Studies have shown losses of >7g salt (sodium chloride) in team sport training sessions (Maughan et al 2004 and Shirreffs et al 2005) Sodium containing fluids (approx 80mmol/L) achieve a more rapid restoration of plasma volume than water due to greater voluntary uptake of fluid and reduced urine output (Nose et al 1988) 1mmol Na = 23mg Na 1g NaCL (salt) contains 390mg (17mmol) of sodium. When large sweat losses occur, fluids containing sodium are more effective at restoring fluid losses during recovery. Fluid with ~50mmol/L sodium most justified for rehydration If sweat losses are minimal (<1kg) and there is time for recovery, water is sufficient. Energy
Estimating energy expenditure
The Schofield Equation is a method of estimating the basal metabolic rate (BMR) of adult men and women
Suggested dietary targets (SDTs)
The amount of a nutrient required to prevent or reduce the risk of chronic disease
RDI (Recommended Dietary Intake)
The average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all (97-98 per cent) healthy individuals in a particular life stage and gender group
EER (Estimated Energy Requirement
The average dietary energy intake that is predicted to maintain energy balance in a healthy adult of defined age, gender, weight, height and level of physical activity, consistent with good health In children and pregnant and lactating women, the EER is taken to include the needs associated with the deposition of tissues or the secretion of milk at rates consistent with good health
Regulation of digestion
The digestion process Gastrointestinal activities are regulated by: Sympathetic nervous system (inhibitory) Parasympathetic nervous system (stimulatory) Enteric nervous system (both stimulatory and inhibitory) Regulatory peptides: Gastrointestinal hormones and neuropeptides
Principles of carbohydrate loading
The glycogen supercompensation protocol derived from this era involved a period of depletion (3 days low carbohydrate of training) followed by a 3-day loading phase (taper of high carbohydrate intake). Today we recognize the importance of considering responses in highly trained individuals and according to the requirements of real sporting events. Subsequent studies around these issues have demonstrated that high glycogen concentrations can be achieved without a depletion phase. A taper of 48-72 hours and a high carbohydrate diet (10-12 grams per kg) achieves similar increases. Carbohydrate loading is a strategy involving changes to training and nutrition that can maximise muscle glycogen (carbohydrate) stores prior to endurance competition. The technique was originally developed in the late 1960's and typically involved a 3-4 day 'depletion phase' involving 3-4 days of hard training plus a low carbohydrate diet. This depletion phase was thought to be necessary to stimulate the enzyme glycogen synthase. This was then followed immediately by a 3-4 day 'loading phase' involving rest combined with a high carbohydrate diet. The combination of the two phases was shown to boost muscle carbohydrate stores beyond their usual resting levels. Ongoing research has allowed the method to be refined so that modern day carbohydrate loading is now more manageable for athletes. The depletion phase was demonstrated to be no longer necessary, Muscle glycogen levels are normally in the range of 100-120 mmol/kg ww (wet weight). Carbohydrate loading enables muscle glycogen levels to be increased to around 150-200 mmol/kg ww. This extra supply of carbohydrate has been demonstrated to improve endurance exercise by allowing athletes to exercise at their optimal pace for a longer time. It is estimated that carbohydrate loading can improve performance over a set distance by 2-3%. Carbohydrate loading requires an exercise taper. Athletes can find it difficult to back off training for 1-4 days before competition. Failing to rest will compromise carbohydrate loading. Anyone exercising continuously at a moderate to high intensity for 90 minutes or longer is likely to benefit from carbohydrate loading. Typically, sports such as cycling, marathon running, longer distance triathlon, cross-country skiing and endurance swimming benefit from carbohydrate loading. Shorter-term exercise is unlikely to benefit as the body's usual carbohydrate stores are adequate. Carbohydrate loading is generally not practical to achieve in team sports where games are played every 3-4 days.
UL (Upper Level of Intake)
The highest average daily nutrient intake level likely to pose no adverse health effects to almost all individuals in the general population As intake increases above the UL, the potential risk of adverse effects increases
Water soluble (a few examples)
Thiamin Riboflavin Niacin Vitamin B6 Vitamin B12 Folate Vitamin C
Digestion & absorption - Large intestine
Unabsorbed materials move from the ileum into the caecum (first section of the large intestine) Contains microflora/bacteria Absorbs predominantly: 90-95% of Water & Sodium Chloride Process takes 12-70 hours 1L of Chyme that enters- results in approx 200g defecated material
AI (Adequate Intake)
Used when an RDI cannot be determined The average daily nutrient intake level based on observed or experimentally-determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate
Fat soluble
Vitamin A Vitamin D Vitamin E Vitamin K
Water & fat soluble vitamins Which are water and which are fat soluble
Vitamins A, D, E, and K are the fat-soluble vitamins. Unlike water-soluble vitamins, these vitamins dissolve in fat and are stored in body tissues. Because they are stored, over time they can accumulate to dangerous levels and can lead to a condition called hypervitaminosis, meaning excess amounts of a vitamin in the body, if more than the recommended amount is taken. "Too much vitamin A, D, or K can lead to increased levels that are unhealthy and can cause health consequences," says Frechman. She adds that too much vitamin A can lead to birth defects, and too high levels of vitamin E may increase the risk of hemorrhaging. Excess vitamin K can lessen or reverse the effect of blood thinner medicines and prevent normal blood clotting. Vitamin D has been one of the more controversial vitamins. Even though it is a fat-soluble vitamin, it appears to be tolerated in the body at higher levels.
Fluid and hydration
Weight loss in kg = loss in ml (500g = 500ml) Sweat rate - 500-1500ml / hour (therefore 500-1500g
Diet / binge cycle
You might pick up on: Dieting, restrictive eating Over-focus on weight/shape/body as critical to performance (may/may not be true) Desire/drive for weight loss Cyclical dieters (many years....) Poor body image Sub-elite athletes more common Elite Athletes....fine line as require certain dietary intake for performance
Gastric emptying rate -
up to 1-1.2L / hour
BMI for population
•Commonly used to report rates of overweight & obesity •Basis of the WHO cut-points: •Association with disease risk
BMI for individuals
•Used as a tool for INDIVIDUAL assessment in conjunction with clinical presentation : •% muscle mass (eg. male athlete) •Skinfolds assessment may be appropriate •Pregnant / postpartum woman •Weight history •'Normal' weight range for elderly is BMI 22-27 •For children, use BMI z-score or age-adjusted growth charts
